    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.text;
    018
    019import java.io.IOException;
    020import java.io.Reader;
    021import java.io.Serializable;
    022import java.io.Writer;
    023import java.nio.CharBuffer;
    024import java.util.Arrays;
    025import java.util.Iterator;
    026import java.util.List;
    027import java.util.Objects;
    028
    029import org.apache.commons.lang3.ArrayUtils;
    030import org.apache.commons.lang3.StringUtils;
    031
    032/**
    033 * Builds a string from constituent parts providing a more flexible and powerful API than {@link StringBuffer} and
    034 * {@link StringBuilder}.
    035 * <p>
    036 * The main differences from StringBuffer/StringBuilder are:
    037 * </p>
    038 * <ul>
    039 * <li>Not synchronized</li>
    040 * <li>Not final</li>
    041 * <li>Subclasses have direct access to character array</li>
    042 * <li>Additional methods
    043 * <ul>
    044 * <li>appendWithSeparators - adds an array of values, with a separator</li>
    045 * <li>appendPadding - adds a length padding characters</li>
    046 * <li>appendFixedLength - adds a fixed width field to the builder</li>
    047 * <li>toCharArray/getChars - simpler ways to get a range of the character array</li>
    048 * <li>delete - delete char or string</li>
    049 * <li>replace - search and replace for a char or string</li>
    050 * <li>leftString/rightString/midString - substring without exceptions</li>
    051 * <li>contains - whether the builder contains a char or string</li>
    052 * <li>size/clear/isEmpty - collections style API methods</li>
    053 * </ul>
    054 * </li>
    055 * <li>Views
    056 * <ul>
    057 * <li>asTokenizer - uses the internal buffer as the source of a StrTokenizer</li>
    058 * <li>asReader - uses the internal buffer as the source of a Reader</li>
    059 * <li>asWriter - allows a Writer to write directly to the internal buffer</li>
    060 * </ul>
    061 * </li>
    062 * </ul>
    063 * <p>
    064 * The aim has been to provide an API that mimics very closely what StringBuffer provides, but with additional methods.
    065 * It should be noted that some edge cases, with invalid indices or null input, have been altered - see individual
    066 * methods. The biggest of these changes is that by default, null will not output the text 'null'. This can be
    067 * controlled by a property, {@link #setNullText(String)}.
    068 * </p>
    069 *
    070 * @since 1.0
    071 * @deprecated Deprecated as of 1.3, use {@link TextStringBuilder} instead. This class will be removed in 2.0.
    072 */
    073@Deprecated
    074public class StrBuilder implements CharSequence, Appendable, Serializable, Builder<String> {
    075
    076    /**
    077     * Inner class to allow StrBuilder to operate as a reader.
    078     */
    079    class StrBuilderReader extends Reader {
    080
    081        /** The current stream position. */
    082        private int pos;
    083
    084        /** The last mark position. */
    085        private int mark;
    086
    087        /**
    088         * Default constructor.
    089         */
    090        StrBuilderReader() {
    091        }
    092
    093        /** {@inheritDoc} */
    094        @Override
    095        public void close() {
    096            // do nothing
    097        }
    098
    099        /** {@inheritDoc} */
    100        @Override
    101        public void mark(final int readAheadLimit) {
    102            mark = pos;
    103        }
    104
    105        /** {@inheritDoc} */
    106        @Override
    107        public boolean markSupported() {
    108            return true;
    109        }
    110
    111        /** {@inheritDoc} */
    112        @Override
    113        public int read() {
    114            if (!ready()) {
    115                return -1;
    116            }
    117            return StrBuilder.this.charAt(pos++);
    118        }
    119
    120        /** {@inheritDoc} */
    121        @Override
    122        public int read(final char[] b, final int off, int len) {
    123            if (off < 0 || len < 0 || off > b.length
    124                    || off + len > b.length || off + len < 0) {
    125                throw new IndexOutOfBoundsException();
    126            }
    127            if (len == 0) {
    128                return 0;
    129            }
    130            if (pos >= StrBuilder.this.size()) {
    131                return -1;
    132            }
    133            if (pos + len > size()) {
    134                len = StrBuilder.this.size() - pos;
    135            }
    136            StrBuilder.this.getChars(pos, pos + len, b, off);
    137            pos += len;
    138            return len;
    139        }
    140
    141        /** {@inheritDoc} */
    142        @Override
    143        public boolean ready() {
    144            return pos < StrBuilder.this.size();
    145        }
    146
    147        /** {@inheritDoc} */
    148        @Override
    149        public void reset() {
    150            pos = mark;
    151        }
    152
    153        /** {@inheritDoc} */
    154        @Override
    155        public long skip(long n) {
    156            if (pos + n > StrBuilder.this.size()) {
    157                n = StrBuilder.this.size() - pos;
    158            }
    159            if (n < 0) {
    160                return 0;
    161            }
    162            pos = Math.addExact(pos, Math.toIntExact(n));
    163            return n;
    164        }
    165    }
    166
    167    /**
    168     * Inner class to allow StrBuilder to operate as a tokenizer.
    169     */
    170    class StrBuilderTokenizer extends StrTokenizer {
    171
    172        /**
    173         * Default constructor.
    174         */
    175        StrBuilderTokenizer() {
    176        }
    177
    178        /** {@inheritDoc} */
    179        @Override
    180        public String getContent() {
    181            final String str = super.getContent();
    182            if (str == null) {
    183                return StrBuilder.this.toString();
    184            }
    185            return str;
    186        }
    187
    188        /** {@inheritDoc} */
    189        @Override
    190        protected List<String> tokenize(final char[] chars, final int offset, final int count) {
    191            if (chars == null) {
    192                return super.tokenize(
    193                        StrBuilder.this.buffer, 0, StrBuilder.this.size());
    194            }
    195            return super.tokenize(chars, offset, count);
    196        }
    197    }
    198
    199    /**
    200     * Inner class to allow StrBuilder to operate as a writer.
    201     */
    202    class StrBuilderWriter extends Writer {
    203
    204        /**
    205         * Default constructor.
    206         */
    207        StrBuilderWriter() {
    208        }
    209
    210        /** {@inheritDoc} */
    211        @Override
    212        public void close() {
    213            // do nothing
    214        }
    215
    216        /** {@inheritDoc} */
    217        @Override
    218        public void flush() {
    219            // do nothing
    220        }
    221
    222        /** {@inheritDoc} */
    223        @Override
    224        public void write(final char[] cbuf) {
    225            StrBuilder.this.append(cbuf);
    226        }
    227
    228        /** {@inheritDoc} */
    229        @Override
    230        public void write(final char[] cbuf, final int off, final int len) {
    231            StrBuilder.this.append(cbuf, off, len);
    232        }
    233
    234        /** {@inheritDoc} */
    235        @Override
    236        public void write(final int c) {
    237            StrBuilder.this.append((char) c);
    238        }
    239
    240        /** {@inheritDoc} */
    241        @Override
    242        public void write(final String str) {
    243            StrBuilder.this.append(str);
    244        }
    245
    246        /** {@inheritDoc} */
    247        @Override
    248        public void write(final String str, final int off, final int len) {
    249            StrBuilder.this.append(str, off, len);
    250        }
    251    }
    252
    253    /**
    254     * The extra capacity for new builders.
    255     */
    256    static final int CAPACITY = 32;
    257
    258    /**
    259     * Required for serialization support.
    260     *
    261     * @see java.io.Serializable
    262     */
    263    private static final long serialVersionUID = 7628716375283629643L;
    264
    265    /** Internal data storage. */
    266    char[] buffer; // package-protected for test code use only
    267
    268    /** Current size of the buffer. */
    269    private int size;
    270
    271    /** The new line. */
    272    private String newLine;
    273
    274    /** The null text. */
    275    private String nullText;
    276
    277    /**
    278     * Constructs an empty builder initial capacity 32 characters.
    279     */
    280    public StrBuilder() {
    281        this(CAPACITY);
    282    }
    283
    284    /**
    285     * Constructs an empty builder the specified initial capacity.
    286     *
    287     * @param initialCapacity  the initial capacity, zero or less will be converted to 32
    288     */
    289    public StrBuilder(int initialCapacity) {
    290        if (initialCapacity <= 0) {
    291            initialCapacity = CAPACITY;
    292        }
    293        buffer = new char[initialCapacity];
    294    }
    295
    296    /**
    297     * Constructs a builder from the string, allocating
    298     * 32 extra characters for growth.
    299     *
    300     * @param str  the string to copy, null treated as blank string
    301     */
    302    public StrBuilder(final String str) {
    303        if (str == null) {
    304            buffer = new char[CAPACITY];
    305        } else {
    306            buffer = new char[str.length() + CAPACITY];
    307            append(str);
    308        }
    309    }
    310
    311    /**
    312     * Appends a boolean value to the string builder.
    313     *
    314     * @param value  the value to append
    315     * @return this, to enable chaining
    316     */
    317    public StrBuilder append(final boolean value) {
    318        if (value) {
    319            ensureCapacity(size + 4);
    320            buffer[size++] = 't';
    321            buffer[size++] = 'r';
    322            buffer[size++] = 'u';
    323            buffer[size++] = 'e';
    324        } else {
    325            ensureCapacity(size + 5);
    326            buffer[size++] = 'f';
    327            buffer[size++] = 'a';
    328            buffer[size++] = 'l';
    329            buffer[size++] = 's';
    330            buffer[size++] = 'e';
    331        }
    332        return this;
    333    }
    334
    335    /**
    336     * Appends a char value to the string builder.
    337     *
    338     * @param ch  the value to append
    339     * @return this, to enable chaining
    340     */
    341    @Override
    342    public StrBuilder append(final char ch) {
    343        final int len = length();
    344        ensureCapacity(len + 1);
    345        buffer[size++] = ch;
    346        return this;
    347    }
    348
    349    /**
    350     * Appends a char array to the string builder.
    351     * Appending null will call {@link #appendNull()}.
    352     *
    353     * @param chars  the char array to append
    354     * @return this, to enable chaining
    355     */
    356    public StrBuilder append(final char[] chars) {
    357        if (chars == null) {
    358            return appendNull();
    359        }
    360        final int strLen = chars.length;
    361        if (strLen > 0) {
    362            final int len = length();
    363            ensureCapacity(len + strLen);
    364            System.arraycopy(chars, 0, buffer, len, strLen);
    365            size += strLen;
    366        }
    367        return this;
    368    }
    369
    370    /**
    371     * Appends a char array to the string builder.
    372     * Appending null will call {@link #appendNull()}.
    373     *
    374     * @param chars  the char array to append
    375     * @param startIndex  the start index, inclusive, must be valid
    376     * @param length  the length to append, must be valid
    377     * @return this, to enable chaining
    378     */
    379    public StrBuilder append(final char[] chars, final int startIndex, final int length) {
    380        if (chars == null) {
    381            return appendNull();
    382        }
    383        if (startIndex < 0 || startIndex > chars.length) {
    384            throw new StringIndexOutOfBoundsException("Invalid startIndex: " + length);
    385        }
    386        if (length < 0 || startIndex + length > chars.length) {
    387            throw new StringIndexOutOfBoundsException("Invalid length: " + length);
    388        }
    389        if (length > 0) {
    390            final int len = length();
    391            ensureCapacity(len + length);
    392            System.arraycopy(chars, startIndex, buffer, len, length);
    393            size += length;
    394        }
    395        return this;
    396    }
    397
    398    /**
    399     * Appends the contents of a char buffer to this string builder.
    400     * Appending null will call {@link #appendNull()}.
    401     *
    402     * @param buf  the char buffer to append
    403     * @return this, to enable chaining
    404     */
    405    public StrBuilder append(final CharBuffer buf) {
    406        if (buf == null) {
    407            return appendNull();
    408        }
    409        if (buf.hasArray()) {
    410            final int length = buf.remaining();
    411            final int len = length();
    412            ensureCapacity(len + length);
    413            System.arraycopy(buf.array(), buf.arrayOffset() + buf.position(), buffer, len, length);
    414            size += length;
    415        } else {
    416            append(buf.toString());
    417        }
    418        return this;
    419    }
    420
    421    /**
    422     * Appends the contents of a char buffer to this string builder.
    423     * Appending null will call {@link #appendNull()}.
    424     *
    425     * @param buf  the char buffer to append
    426     * @param startIndex  the start index, inclusive, must be valid
    427     * @param length  the length to append, must be valid
    428     * @return this, to enable chaining
    429     */
    430    public StrBuilder append(final CharBuffer buf, final int startIndex, final int length) {
    431        if (buf == null) {
    432            return appendNull();
    433        }
    434        if (buf.hasArray()) {
    435            final int totalLength = buf.remaining();
    436            if (startIndex < 0 || startIndex > totalLength) {
    437                throw new StringIndexOutOfBoundsException("startIndex must be valid");
    438            }
    439            if (length < 0 || startIndex + length > totalLength) {
    440                throw new StringIndexOutOfBoundsException("length must be valid");
    441            }
    442            final int len = length();
    443            ensureCapacity(len + length);
    444            System.arraycopy(buf.array(), buf.arrayOffset() + buf.position() + startIndex, buffer, len, length);
    445            size += length;
    446        } else {
    447            append(buf.toString(), startIndex, length);
    448        }
    449        return this;
    450    }
    451
    452    /**
    453     * Appends a CharSequence to this string builder.
    454     * Appending null will call {@link #appendNull()}.
    455     *
    456     * @param seq  the CharSequence to append
    457     * @return this, to enable chaining
    458     */
    459    @Override
    460    public StrBuilder append(final CharSequence seq) {
    461        if (seq == null) {
    462            return appendNull();
    463        }
    464        if (seq instanceof StrBuilder) {
    465            return append((StrBuilder) seq);
    466        }
    467        if (seq instanceof StringBuilder) {
    468            return append((StringBuilder) seq);
    469        }
    470        if (seq instanceof StringBuffer) {
    471            return append((StringBuffer) seq);
    472        }
    473        if (seq instanceof CharBuffer) {
    474            return append((CharBuffer) seq);
    475        }
    476        return append(seq.toString());
    477    }
    478
    479    /**
    480     * Appends part of a CharSequence to this string builder.
    481     * Appending null will call {@link #appendNull()}.
    482     *
    483     * @param seq  the CharSequence to append
    484     * @param startIndex  the start index, inclusive, must be valid
    485     * @param length  the length to append, must be valid
    486     * @return this, to enable chaining
    487     */
    488    @Override
    489    public StrBuilder append(final CharSequence seq, final int startIndex, final int length) {
    490        if (seq == null) {
    491            return appendNull();
    492        }
    493        return append(seq.toString(), startIndex, length);
    494    }
    495
    496    /**
    497     * Appends a double value to the string builder using {@code String.valueOf}.
    498     *
    499     * @param value  the value to append
    500     * @return this, to enable chaining
    501     */
    502    public StrBuilder append(final double value) {
    503        return append(String.valueOf(value));
    504    }
    505
    506    /**
    507     * Appends a float value to the string builder using {@code String.valueOf}.
    508     *
    509     * @param value  the value to append
    510     * @return this, to enable chaining
    511     */
    512    public StrBuilder append(final float value) {
    513        return append(String.valueOf(value));
    514    }
    515
    516    /**
    517     * Appends an int value to the string builder using {@code String.valueOf}.
    518     *
    519     * @param value  the value to append
    520     * @return this, to enable chaining
    521     */
    522    public StrBuilder append(final int value) {
    523        return append(String.valueOf(value));
    524    }
    525
    526    /**
    527     * Appends a long value to the string builder using {@code String.valueOf}.
    528     *
    529     * @param value  the value to append
    530     * @return this, to enable chaining
    531     */
    532    public StrBuilder append(final long value) {
    533        return append(String.valueOf(value));
    534    }
    535
    536    /**
    537     * Appends an object to this string builder.
    538     * Appending null will call {@link #appendNull()}.
    539     *
    540     * @param obj  the object to append
    541     * @return this, to enable chaining
    542     */
    543    public StrBuilder append(final Object obj) {
    544        if (obj == null) {
    545            return appendNull();
    546        }
    547        if (obj instanceof CharSequence) {
    548            return append((CharSequence) obj);
    549        }
    550        return append(obj.toString());
    551    }
    552
    553    /**
    554     * Appends another string builder to this string builder.
    555     * Appending null will call {@link #appendNull()}.
    556     *
    557     * @param str  the string builder to append
    558     * @return this, to enable chaining
    559     */
    560    public StrBuilder append(final StrBuilder str) {
    561        if (str == null) {
    562            return appendNull();
    563        }
    564        final int strLen = str.length();
    565        if (strLen > 0) {
    566            final int len = length();
    567            ensureCapacity(len + strLen);
    568            System.arraycopy(str.buffer, 0, buffer, len, strLen);
    569            size += strLen;
    570        }
    571        return this;
    572    }
    573
    574    /**
    575     * Appends part of a string builder to this string builder.
    576     * Appending null will call {@link #appendNull()}.
    577     *
    578     * @param str  the string to append
    579     * @param startIndex  the start index, inclusive, must be valid
    580     * @param length  the length to append, must be valid
    581     * @return this, to enable chaining
    582     */
    583    public StrBuilder append(final StrBuilder str, final int startIndex, final int length) {
    584        if (str == null) {
    585            return appendNull();
    586        }
    587        if (startIndex < 0 || startIndex > str.length()) {
    588            throw new StringIndexOutOfBoundsException("startIndex must be valid");
    589        }
    590        if (length < 0 || startIndex + length > str.length()) {
    591            throw new StringIndexOutOfBoundsException("length must be valid");
    592        }
    593        if (length > 0) {
    594            final int len = length();
    595            ensureCapacity(len + length);
    596            str.getChars(startIndex, startIndex + length, buffer, len);
    597            size += length;
    598        }
    599        return this;
    600    }
    601
    602    /**
    603     * Appends a string to this string builder.
    604     * Appending null will call {@link #appendNull()}.
    605     *
    606     * @param str  the string to append
    607     * @return this, to enable chaining
    608     */
    609    public StrBuilder append(final String str) {
    610        if (str == null) {
    611            return appendNull();
    612        }
    613        final int strLen = str.length();
    614        if (strLen > 0) {
    615            final int len = length();
    616            ensureCapacity(len + strLen);
    617            str.getChars(0, strLen, buffer, len);
    618            size += strLen;
    619        }
    620        return this;
    621    }
    622
    623    /**
    624     * Appends part of a string to this string builder.
    625     * Appending null will call {@link #appendNull()}.
    626     *
    627     * @param str  the string to append
    628     * @param startIndex  the start index, inclusive, must be valid
    629     * @param length  the length to append, must be valid
    630     * @return this, to enable chaining
    631     */
    632    public StrBuilder append(final String str, final int startIndex, final int length) {
    633        if (str == null) {
    634            return appendNull();
    635        }
    636        if (startIndex < 0 || startIndex > str.length()) {
    637            throw new StringIndexOutOfBoundsException("startIndex must be valid");
    638        }
    639        if (length < 0 || startIndex + length > str.length()) {
    640            throw new StringIndexOutOfBoundsException("length must be valid");
    641        }
    642        if (length > 0) {
    643            final int len = length();
    644            ensureCapacity(len + length);
    645            str.getChars(startIndex, startIndex + length, buffer, len);
    646            size += length;
    647        }
    648        return this;
    649    }
    650
    651    /**
    652     * Calls {@link String#format(String, Object...)} and appends the result.
    653     *
    654     * @param format the format string
    655     * @param objs the objects to use in the format string
    656     * @return {@code this} to enable chaining
    657     * @see String#format(String, Object...)
    658     */
    659    public StrBuilder append(final String format, final Object... objs) {
    660        return append(String.format(format, objs));
    661    }
    662
    663    /**
    664     * Appends a string buffer to this string builder.
    665     * Appending null will call {@link #appendNull()}.
    666     *
    667     * @param str  the string buffer to append
    668     * @return this, to enable chaining
    669     */
    670    public StrBuilder append(final StringBuffer str) {
    671        if (str == null) {
    672            return appendNull();
    673        }
    674        final int strLen = str.length();
    675        if (strLen > 0) {
    676            final int len = length();
    677            ensureCapacity(len + strLen);
    678            str.getChars(0, strLen, buffer, len);
    679            size += strLen;
    680        }
    681        return this;
    682    }
    683
    684    /**
    685     * Appends part of a string buffer to this string builder.
    686     * Appending null will call {@link #appendNull()}.
    687     *
    688     * @param str  the string to append
    689     * @param startIndex  the start index, inclusive, must be valid
    690     * @param length  the length to append, must be valid
    691     * @return this, to enable chaining
    692     */
    693    public StrBuilder append(final StringBuffer str, final int startIndex, final int length) {
    694        if (str == null) {
    695            return appendNull();
    696        }
    697        if (startIndex < 0 || startIndex > str.length()) {
    698            throw new StringIndexOutOfBoundsException("startIndex must be valid");
    699        }
    700        if (length < 0 || startIndex + length > str.length()) {
    701            throw new StringIndexOutOfBoundsException("length must be valid");
    702        }
    703        if (length > 0) {
    704            final int len = length();
    705            ensureCapacity(len + length);
    706            str.getChars(startIndex, startIndex + length, buffer, len);
    707            size += length;
    708        }
    709        return this;
    710    }
    711
    712    /**
    713     * Appends a StringBuilder to this string builder.
    714     * Appending null will call {@link #appendNull()}.
    715     *
    716     * @param str the StringBuilder to append
    717     * @return this, to enable chaining
    718     */
    719    public StrBuilder append(final StringBuilder str) {
    720        if (str == null) {
    721            return appendNull();
    722        }
    723        final int strLen = str.length();
    724        if (strLen > 0) {
    725            final int len = length();
    726            ensureCapacity(len + strLen);
    727            str.getChars(0, strLen, buffer, len);
    728            size += strLen;
    729        }
    730        return this;
    731    }
    732
    733    /**
    734     * Appends part of a StringBuilder to this string builder.
    735     * Appending null will call {@link #appendNull()}.
    736     *
    737     * @param str the StringBuilder to append
    738     * @param startIndex the start index, inclusive, must be valid
    739     * @param length the length to append, must be valid
    740     * @return this, to enable chaining
    741     */
    742    public StrBuilder append(final StringBuilder str, final int startIndex, final int length) {
    743        if (str == null) {
    744            return appendNull();
    745        }
    746        if (startIndex < 0 || startIndex > str.length()) {
    747            throw new StringIndexOutOfBoundsException("startIndex must be valid");
    748        }
    749        if (length < 0 || startIndex + length > str.length()) {
    750            throw new StringIndexOutOfBoundsException("length must be valid");
    751        }
    752        if (length > 0) {
    753            final int len = length();
    754            ensureCapacity(len + length);
    755            str.getChars(startIndex, startIndex + length, buffer, len);
    756            size += length;
    757        }
    758        return this;
    759    }
    760
    761    /**
    762     * Appends each item in an iterable to the builder without any separators.
    763     * Appending a null iterable will have no effect.
    764     * Each object is appended using {@link #append(Object)}.
    765     *
    766     * @param iterable  the iterable to append
    767     * @return this, to enable chaining
    768     */
    769    public StrBuilder appendAll(final Iterable<?> iterable) {
    770        if (iterable != null) {
    771            iterable.forEach(this::append);
    772        }
    773        return this;
    774    }
    775
    776    /**
    777     * Appends each item in an iterator to the builder without any separators.
    778     * Appending a null iterator will have no effect.
    779     * Each object is appended using {@link #append(Object)}.
    780     *
    781     * @param it  the iterator to append
    782     * @return this, to enable chaining
    783     */
    784    public StrBuilder appendAll(final Iterator<?> it) {
    785        if (it != null) {
    786            while (it.hasNext()) {
    787                append(it.next());
    788            }
    789        }
    790        return this;
    791    }
    792
    793    /**
    794     * Appends each item in an array to the builder without any separators.
    795     * Appending a null array will have no effect.
    796     * Each object is appended using {@link #append(Object)}.
    797     *
    798     * @param <T>  the element type
    799     * @param array  the array to append
    800     * @return this, to enable chaining
    801     */
    802    public <T> StrBuilder appendAll(@SuppressWarnings("unchecked") final T... array) {
    803        /*
    804         * @SuppressWarnings used to hide warning about vararg usage. We cannot
    805         * use @SafeVarargs, since this method is not final. Using @SuppressWarnings
    806         * is fine, because it isn't inherited by subclasses, so each subclass must
    807         * vouch for itself whether its use of 'array' is safe.
    808         */
    809        if (array != null && array.length > 0) {
    810            for (final Object element : array) {
    811                append(element);
    812            }
    813        }
    814        return this;
    815    }
    816
    817    /**
    818     * Appends an object to the builder padding on the left to a fixed width.
    819     * The {@code String.valueOf} of the {@code int} value is used.
    820     * If the formatted value is larger than the length, the left hand side is lost.
    821     *
    822     * @param value  the value to append
    823     * @param width  the fixed field width, zero or negative has no effect
    824     * @param padChar  the pad character to use
    825     * @return this, to enable chaining
    826     */
    827    public StrBuilder appendFixedWidthPadLeft(final int value, final int width, final char padChar) {
    828        return appendFixedWidthPadLeft(String.valueOf(value), width, padChar);
    829    }
    830
    831    /**
    832     * Appends an object to the builder padding on the left to a fixed width.
    833     * The {@code toString} of the object is used.
    834     * If the object is larger than the length, the left hand side is lost.
    835     * If the object is null, the null text value is used.
    836     *
    837     * @param obj  the object to append, null uses null text
    838     * @param width  the fixed field width, zero or negative has no effect
    839     * @param padChar  the pad character to use
    840     * @return this, to enable chaining
    841     */
    842    public StrBuilder appendFixedWidthPadLeft(final Object obj, final int width, final char padChar) {
    843        if (width > 0) {
    844            ensureCapacity(size + width);
    845            String str = obj == null ? getNullText() : obj.toString();
    846            if (str == null) {
    847                str = StringUtils.EMPTY;
    848            }
    849            final int strLen = str.length();
    850            if (strLen >= width) {
    851                str.getChars(strLen - width, strLen, buffer, size);
    852            } else {
    853                final int padLen = width - strLen;
    854                for (int i = 0; i < padLen; i++) {
    855                    buffer[size + i] = padChar;
    856                }
    857                str.getChars(0, strLen, buffer, size + padLen);
    858            }
    859            size += width;
    860        }
    861        return this;
    862    }
    863
    864    /**
    865     * Appends an object to the builder padding on the right to a fixed length.
    866     * The {@code String.valueOf} of the {@code int} value is used.
    867     * If the object is larger than the length, the right hand side is lost.
    868     *
    869     * @param value  the value to append
    870     * @param width  the fixed field width, zero or negative has no effect
    871     * @param padChar  the pad character to use
    872     * @return this, to enable chaining
    873     */
    874    public StrBuilder appendFixedWidthPadRight(final int value, final int width, final char padChar) {
    875        return appendFixedWidthPadRight(String.valueOf(value), width, padChar);
    876    }
    877
    878    /**
    879     * Appends an object to the builder padding on the right to a fixed length.
    880     * The {@code toString} of the object is used.
    881     * If the object is larger than the length, the right hand side is lost.
    882     * If the object is null, null text value is used.
    883     *
    884     * @param obj  the object to append, null uses null text
    885     * @param width  the fixed field width, zero or negative has no effect
    886     * @param padChar  the pad character to use
    887     * @return this, to enable chaining
    888     */
    889    public StrBuilder appendFixedWidthPadRight(final Object obj, final int width, final char padChar) {
    890        if (width > 0) {
    891            ensureCapacity(size + width);
    892            String str = obj == null ? getNullText() : obj.toString();
    893            if (str == null) {
    894                str = StringUtils.EMPTY;
    895            }
    896            final int strLen = str.length();
    897            if (strLen >= width) {
    898                str.getChars(0, width, buffer, size);
    899            } else {
    900                final int padLen = width - strLen;
    901                str.getChars(0, strLen, buffer, size);
    902                for (int i = 0; i < padLen; i++) {
    903                    buffer[size + strLen + i] = padChar;
    904                }
    905            }
    906            size += width;
    907        }
    908        return this;
    909    }
    910
    911    /**
    912     * Appends a boolean value followed by a new line to the string builder.
    913     *
    914     * @param value  the value to append
    915     * @return this, to enable chaining
    916     */
    917    public StrBuilder appendln(final boolean value) {
    918        return append(value).appendNewLine();
    919    }
    920
    921    /**
    922     * Appends a char value followed by a new line to the string builder.
    923     *
    924     * @param ch  the value to append
    925     * @return this, to enable chaining
    926     */
    927    public StrBuilder appendln(final char ch) {
    928        return append(ch).appendNewLine();
    929    }
    930
    931    /**
    932     * Appends a char array followed by a new line to the string builder.
    933     * Appending null will call {@link #appendNull()}.
    934     *
    935     * @param chars  the char array to append
    936     * @return this, to enable chaining
    937     */
    938    public StrBuilder appendln(final char[] chars) {
    939        return append(chars).appendNewLine();
    940    }
    941
    942    /**
    943     * Appends a char array followed by a new line to the string builder.
    944     * Appending null will call {@link #appendNull()}.
    945     *
    946     * @param chars  the char array to append
    947     * @param startIndex  the start index, inclusive, must be valid
    948     * @param length  the length to append, must be valid
    949     * @return this, to enable chaining
    950     */
    951    public StrBuilder appendln(final char[] chars, final int startIndex, final int length) {
    952        return append(chars, startIndex, length).appendNewLine();
    953    }
    954
    955    /**
    956     * Appends a double value followed by a new line to the string builder using {@code String.valueOf}.
    957     *
    958     * @param value  the value to append
    959     * @return this, to enable chaining
    960     */
    961    public StrBuilder appendln(final double value) {
    962        return append(value).appendNewLine();
    963    }
    964
    965    /**
    966     * Appends a float value followed by a new line to the string builder using {@code String.valueOf}.
    967     *
    968     * @param value  the value to append
    969     * @return this, to enable chaining
    970     */
    971    public StrBuilder appendln(final float value) {
    972        return append(value).appendNewLine();
    973    }
    974
    975    /**
    976     * Appends an int value followed by a new line to the string builder using {@code String.valueOf}.
    977     *
    978     * @param value  the value to append
    979     * @return this, to enable chaining
    980     */
    981    public StrBuilder appendln(final int value) {
    982        return append(value).appendNewLine();
    983    }
    984
    985    /**
    986     * Appends a long value followed by a new line to the string builder using {@code String.valueOf}.
    987     *
    988     * @param value  the value to append
    989     * @return this, to enable chaining
    990     */
    991    public StrBuilder appendln(final long value) {
    992        return append(value).appendNewLine();
    993    }
    994
    995    /**
    996     * Appends an object followed by a new line to this string builder.
    997     * Appending null will call {@link #appendNull()}.
    998     *
    999     * @param obj  the object to append
    1000     * @return this, to enable chaining
    1001     */
    1002    public StrBuilder appendln(final Object obj) {
    1003        return append(obj).appendNewLine();
    1004    }
    1005
    1006    /**
    1007     * Appends another string builder followed by a new line to this string builder.
    1008     * Appending null will call {@link #appendNull()}.
    1009     *
    1010     * @param str  the string builder to append
    1011     * @return this, to enable chaining
    1012     */
    1013    public StrBuilder appendln(final StrBuilder str) {
    1014        return append(str).appendNewLine();
    1015    }
    1016
    1017    /**
    1018     * Appends part of a string builder followed by a new line to this string builder.
    1019     * Appending null will call {@link #appendNull()}.
    1020     *
    1021     * @param str  the string to append
    1022     * @param startIndex  the start index, inclusive, must be valid
    1023     * @param length  the length to append, must be valid
    1024     * @return this, to enable chaining
    1025     */
    1026    public StrBuilder appendln(final StrBuilder str, final int startIndex, final int length) {
    1027        return append(str, startIndex, length).appendNewLine();
    1028    }
    1029
    1030    /**
    1031     * Appends a string followed by a new line to this string builder.
    1032     * Appending null will call {@link #appendNull()}.
    1033     *
    1034     * @param str  the string to append
    1035     * @return this, to enable chaining
    1036     */
    1037    public StrBuilder appendln(final String str) {
    1038        return append(str).appendNewLine();
    1039    }
    1040
    1041    /**
    1042     * Appends part of a string followed by a new line to this string builder.
    1043     * Appending null will call {@link #appendNull()}.
    1044     *
    1045     * @param str  the string to append
    1046     * @param startIndex  the start index, inclusive, must be valid
    1047     * @param length  the length to append, must be valid
    1048     * @return this, to enable chaining
    1049     */
    1050    public StrBuilder appendln(final String str, final int startIndex, final int length) {
    1051        return append(str, startIndex, length).appendNewLine();
    1052    }
    1053
    1054    /**
    1055     * Calls {@link String#format(String, Object...)} and appends the result.
    1056     *
    1057     * @param format the format string
    1058     * @param objs the objects to use in the format string
    1059     * @return {@code this} to enable chaining
    1060     * @see String#format(String, Object...)
    1061     */
    1062    public StrBuilder appendln(final String format, final Object... objs) {
    1063        return append(format, objs).appendNewLine();
    1064    }
    1065
    1066    /**
    1067     * Appends a string buffer followed by a new line to this string builder.
    1068     * Appending null will call {@link #appendNull()}.
    1069     *
    1070     * @param str  the string buffer to append
    1071     * @return this, to enable chaining
    1072     */
    1073    public StrBuilder appendln(final StringBuffer str) {
    1074        return append(str).appendNewLine();
    1075    }
    1076
    1077    /**
    1078     * Appends part of a string buffer followed by a new line to this string builder.
    1079     * Appending null will call {@link #appendNull()}.
    1080     *
    1081     * @param str  the string to append
    1082     * @param startIndex  the start index, inclusive, must be valid
    1083     * @param length  the length to append, must be valid
    1084     * @return this, to enable chaining
    1085     */
    1086    public StrBuilder appendln(final StringBuffer str, final int startIndex, final int length) {
    1087        return append(str, startIndex, length).appendNewLine();
    1088    }
    1089
    1090    /**
    1091     * Appends a string builder followed by a new line to this string builder.
    1092     * Appending null will call {@link #appendNull()}.
    1093     *
    1094     * @param str  the string builder to append
    1095     * @return this, to enable chaining
    1096     */
    1097    public StrBuilder appendln(final StringBuilder str) {
    1098        return append(str).appendNewLine();
    1099    }
    1100
    1101    /**
    1102     * Appends part of a string builder followed by a new line to this string builder.
    1103     * Appending null will call {@link #appendNull()}.
    1104     *
    1105     * @param str  the string builder to append
    1106     * @param startIndex  the start index, inclusive, must be valid
    1107     * @param length  the length to append, must be valid
    1108     * @return this, to enable chaining
    1109     */
    1110    public StrBuilder appendln(final StringBuilder str, final int startIndex, final int length) {
    1111        return append(str, startIndex, length).appendNewLine();
    1112    }
    1113
    1114    /**
    1115     * Appends the new line string to this string builder.
    1116     * <p>
    1117     * The new line string can be altered using {@link #setNewLineText(String)}.
    1118     * This might be used to force the output to always use Unix line endings
    1119     * even when on Windows.
    1120     * </p>
    1121     * @return this, to enable chaining
    1122     */
    1123    public StrBuilder appendNewLine() {
    1124        if (newLine == null)  {
    1125            append(System.lineSeparator());
    1126            return this;
    1127        }
    1128        return append(newLine);
    1129    }
    1130
    1131    /**
    1132     * Appends the text representing {@code null} to this string builder.
    1133     *
    1134     * @return this, to enable chaining
    1135     */
    1136    public StrBuilder appendNull() {
    1137        if (nullText == null)  {
    1138            return this;
    1139        }
    1140        return append(nullText);
    1141    }
    1142
    1143    /**
    1144     * Appends the pad character to the builder the specified number of times.
    1145     *
    1146     * @param length  the length to append, negative means no append
    1147     * @param padChar  the character to append
    1148     * @return this, to enable chaining
    1149     */
    1150    public StrBuilder appendPadding(final int length, final char padChar) {
    1151        if (length >= 0) {
    1152            ensureCapacity(size + length);
    1153            for (int i = 0; i < length; i++) {
    1154                buffer[size++] = padChar;
    1155            }
    1156        }
    1157        return this;
    1158    }
    1159
    1160    /**
    1161     * Appends a separator if the builder is currently non-empty.
    1162     * The separator is appended using {@link #append(char)}.
    1163     * <p>
    1164     * This method is useful for adding a separator each time around the
    1165     * loop except the first.
    1166     * </p>
    1167     * <pre>
    1168     * for (Iterator it = list.iterator(); it.hasNext();){
    1169     *   appendSeparator(',');
    1170     *   append(it.next());
    1171     * }
    1172     * </pre>
    1173     * <p>
    1174     * Note that for this simple example, you should use
    1175     * {@link #appendWithSeparators(Iterable, String)}.
    1176     * </p>
    1177     *
    1178     * @param separator  the separator to use
    1179     * @return this, to enable chaining
    1180     */
    1181    public StrBuilder appendSeparator(final char separator) {
    1182        if (isNotEmpty()) {
    1183            append(separator);
    1184        }
    1185        return this;
    1186    }
    1187
    1188    /**
    1189     * Appends one of both separators to the builder
    1190     * If the builder is currently empty it will append the defaultIfEmpty-separator
    1191     * Otherwise it will append the standard-separator
    1192     *
    1193     * The separator is appended using {@link #append(char)}.
    1194     * @param standard the separator if builder is not empty
    1195     * @param defaultIfEmpty the separator if builder is empty
    1196     * @return this, to enable chaining
    1197     */
    1198    public StrBuilder appendSeparator(final char standard, final char defaultIfEmpty) {
    1199        if (isNotEmpty()) {
    1200            append(standard);
    1201        } else {
    1202            append(defaultIfEmpty);
    1203        }
    1204        return this;
    1205    }
    1206
    1207    /**
    1208     * Appends a separator to the builder if the loop index is greater than zero.
    1209     * The separator is appended using {@link #append(char)}.
    1210     * <p>
    1211     * This method is useful for adding a separator each time around the
    1212     * loop except the first.
    1213     * </p>
    1214     * <pre>
    1215     * for (int i = 0; i &lt; list.size(); i++) {
    1216     *   appendSeparator(",", i);
    1217     *   append(list.get(i));
    1218     * }
    1219     * </pre>
    1220     * <p>
    1221     * Note that for this simple example, you should use
    1222     * {@link #appendWithSeparators(Iterable, String)}.
    1223     * </p>
    1224     *
    1225     * @param separator  the separator to use
    1226     * @param loopIndex  the loop index
    1227     * @return this, to enable chaining
    1228     */
    1229    public StrBuilder appendSeparator(final char separator, final int loopIndex) {
    1230        if (loopIndex > 0) {
    1231            append(separator);
    1232        }
    1233        return this;
    1234    }
    1235
    1236    /**
    1237     * Appends a separator if the builder is currently non-empty.
    1238     * Appending a null separator will have no effect.
    1239     * The separator is appended using {@link #append(String)}.
    1240     * <p>
    1241     * This method is useful for adding a separator each time around the
    1242     * loop except the first.
    1243     * </p>
    1244     * <pre>
    1245     * for (Iterator it = list.iterator(); it.hasNext();){
    1246     *   appendSeparator(",");
    1247     *   append(it.next());
    1248     * }
    1249     * </pre>
    1250     * <p>
    1251     * Note that for this simple example, you should use
    1252     * {@link #appendWithSeparators(Iterable, String)}.
    1253     * </p>
    1254     *
    1255     * @param separator  the separator to use, null means no separator
    1256     * @return this, to enable chaining
    1257     */
    1258    public StrBuilder appendSeparator(final String separator) {
    1259        return appendSeparator(separator, null);
    1260    }
    1261
    1262    /**
    1263     * Appends a separator to the builder if the loop index is greater than zero.
    1264     * Appending a null separator will have no effect.
    1265     * The separator is appended using {@link #append(String)}.
    1266     * <p>
    1267     * This method is useful for adding a separator each time around the
    1268     * loop except the first.
    1269     * </p>
    1270     * <pre>
    1271     * for (int i = 0; i &lt; list.size(); i++) {
    1272     *   appendSeparator(",", i);
    1273     *   append(list.get(i));
    1274     * }
    1275     * </pre>
    1276     * <p>
    1277     * Note that for this simple example, you should use
    1278     * {@link #appendWithSeparators(Iterable, String)}.
    1279     * </p>
    1280     *
    1281     * @param separator  the separator to use, null means no separator
    1282     * @param loopIndex  the loop index
    1283     * @return this, to enable chaining
    1284     */
    1285    public StrBuilder appendSeparator(final String separator, final int loopIndex) {
    1286        if (separator != null && loopIndex > 0) {
    1287            append(separator);
    1288        }
    1289        return this;
    1290    }
    1291
    1292    /**
    1293     * Appends one of both separators to the StrBuilder.
    1294     * If the builder is currently empty it will append the defaultIfEmpty-separator
    1295     * Otherwise it will append the standard-separator
    1296     * <p>
    1297     * Appending a null separator will have no effect.
    1298     * The separator is appended using {@link #append(String)}.
    1299     * </p>
    1300     * <p>
    1301     * This method is for example useful for constructing queries
    1302     * </p>
    1303     * <pre>
    1304     * StrBuilder whereClause = new StrBuilder();
    1305     * if (searchCommand.getPriority() != null) {
    1306     *   whereClause.appendSeparator(" and", " where");
    1307     *   whereClause.append(" priority = ?")
    1308     * }
    1309     * if (searchCommand.getComponent() != null) {
    1310     *   whereClause.appendSeparator(" and", " where");
    1311     *   whereClause.append(" component = ?")
    1312     * }
    1313     * selectClause.append(whereClause)
    1314     * </pre>
    1315     *
    1316     * @param standard the separator if builder is not empty, null means no separator
    1317     * @param defaultIfEmpty the separator if builder is empty, null means no separator
    1318     * @return this, to enable chaining
    1319     */
    1320    public StrBuilder appendSeparator(final String standard, final String defaultIfEmpty) {
    1321        final String str = isEmpty() ? defaultIfEmpty : standard;
    1322        if (str != null) {
    1323            append(str);
    1324        }
    1325        return this;
    1326    }
    1327
    1328    /**
    1329     * Appends current contents of this {@code StrBuilder} to the
    1330     * provided {@link Appendable}.
    1331     * <p>
    1332     * This method tries to avoid doing any extra copies of contents.
    1333     * </p>
    1334     *
    1335     * @param appendable  the appendable to append data to
    1336     * @throws IOException  if an I/O error occurs
    1337     *
    1338     * @see #readFrom(Readable)
    1339     */
    1340    public void appendTo(final Appendable appendable) throws IOException {
    1341        if (appendable instanceof Writer) {
    1342            ((Writer) appendable).write(buffer, 0, size);
    1343        } else if (appendable instanceof StringBuilder) {
    1344            ((StringBuilder) appendable).append(buffer, 0, size);
    1345        } else if (appendable instanceof StringBuffer) {
    1346            ((StringBuffer) appendable).append(buffer, 0, size);
    1347        } else if (appendable instanceof CharBuffer) {
    1348            ((CharBuffer) appendable).put(buffer, 0, size);
    1349        } else {
    1350            appendable.append(this);
    1351        }
    1352    }
    1353
    1354    /**
    1355     * Appends an iterable placing separators between each value, but
    1356     * not before the first or after the last.
    1357     * Appending a null iterable will have no effect.
    1358     * Each object is appended using {@link #append(Object)}.
    1359     *
    1360     * @param iterable  the iterable to append
    1361     * @param separator  the separator to use, null means no separator
    1362     * @return this, to enable chaining
    1363     */
    1364    public StrBuilder appendWithSeparators(final Iterable<?> iterable, final String separator) {
    1365        if (iterable != null) {
    1366            appendWithSeparators(iterable.iterator(), separator);
    1367        }
    1368        return this;
    1369    }
    1370
    1371    /**
    1372     * Appends an iterator placing separators between each value, but
    1373     * not before the first or after the last.
    1374     * Appending a null iterator will have no effect.
    1375     * Each object is appended using {@link #append(Object)}.
    1376     *
    1377     * @param iterator  the iterator to append
    1378     * @param separator  the separator to use, null means no separator
    1379     * @return this, to enable chaining
    1380     */
    1381    public StrBuilder appendWithSeparators(final Iterator<?> iterator, final String separator) {
    1382        if (iterator != null) {
    1383            final String sep = Objects.toString(separator, StringUtils.EMPTY);
    1384            while (iterator.hasNext()) {
    1385                append(iterator.next());
    1386                if (iterator.hasNext()) {
    1387                    append(sep);
    1388                }
    1389            }
    1390        }
    1391        return this;
    1392    }
    1393
    1394    /**
    1395     * Appends an array placing separators between each value, but
    1396     * not before the first or after the last.
    1397     * Appending a null array will have no effect.
    1398     * Each object is appended using {@link #append(Object)}.
    1399     *
    1400     * @param array  the array to append
    1401     * @param separator  the separator to use, null means no separator
    1402     * @return this, to enable chaining
    1403     */
    1404    public StrBuilder appendWithSeparators(final Object[] array, final String separator) {
    1405        if (array != null && array.length > 0) {
    1406            final String sep = Objects.toString(separator, StringUtils.EMPTY);
    1407            append(array[0]);
    1408            for (int i = 1; i < array.length; i++) {
    1409                append(sep);
    1410                append(array[i]);
    1411            }
    1412        }
    1413        return this;
    1414    }
    1415
    1416    /**
    1417     * Gets the contents of this builder as a Reader.
    1418     * <p>
    1419     * This method allows the contents of the builder to be read
    1420     * using any standard method that expects a Reader.
    1421     * </p>
    1422     * <p>
    1423     * To use, simply create a {@code StrBuilder}, populate it with
    1424     * data, call {@code asReader}, and then read away.
    1425     * </p>
    1426     * <p>
    1427     * The internal character array is shared between the builder and the reader.
    1428     * This allows you to append to the builder after creating the reader,
    1429     * and the changes will be picked up.
    1430     * Note however, that no synchronization occurs, so you must perform
    1431     * all operations with the builder and the reader in one thread.
    1432     * </p>
    1433     * <p>
    1434     * The returned reader supports marking, and ignores the flush method.
    1435     * </p>
    1436     *
    1437     * @return a reader that reads from this builder
    1438     */
    1439    public Reader asReader() {
    1440        return new StrBuilderReader();
    1441    }
    1442
    1443    /**
    1444     * Creates a tokenizer that can tokenize the contents of this builder.
    1445     * <p>
    1446     * This method allows the contents of this builder to be tokenized.
    1447     * The tokenizer will be setup by default to tokenize on space, tab,
    1448     * newline and form feed (as per StringTokenizer). These values can be
    1449     * changed on the tokenizer class, before retrieving the tokens.
    1450     * </p>
    1451     * <p>
    1452     * The returned tokenizer is linked to this builder. You may intermix
    1453     * calls to the builder and tokenizer within certain limits, however
    1454     * there is no synchronization. Once the tokenizer has been used once,
    1455     * it must be {@link StrTokenizer#reset() reset} to pickup the latest
    1456     * changes in the builder. For example:
    1457     * </p>
    1458     * <pre>
    1459     * StrBuilder b = new StrBuilder();
    1460     * b.append("a b ");
    1461     * StrTokenizer t = b.asTokenizer();
    1462     * String[] tokens1 = t.getTokenArray();  // returns a,b
    1463     * b.append("c d ");
    1464     * String[] tokens2 = t.getTokenArray();  // returns a,b (c and d ignored)
    1465     * t.reset();              // reset causes builder changes to be picked up
    1466     * String[] tokens3 = t.getTokenArray();  // returns a,b,c,d
    1467     * </pre>
    1468     * <p>
    1469     * In addition to simply intermixing appends and tokenization, you can also
    1470     * call the set methods on the tokenizer to alter how it tokenizes. Just
    1471     * remember to call reset when you want to pickup builder changes.
    1472     * </p>
    1473     * <p>
    1474     * Calling {@link StrTokenizer#reset(String)} or {@link StrTokenizer#reset(char[])}
    1475     * with a non-null value will break the link with the builder.
    1476     * </p>
    1477     *
    1478     * @return a tokenizer that is linked to this builder
    1479     */
    1480    public StrTokenizer asTokenizer() {
    1481        return new StrBuilderTokenizer();
    1482    }
    1483
    1484    /**
    1485     * Gets this builder as a Writer that can be written to.
    1486     * <p>
    1487     * This method allows you to populate the contents of the builder
    1488     * using any standard method that takes a Writer.
    1489     * </p>
    1490     * <p>
    1491     * To use, simply create a {@code StrBuilder},
    1492     * call {@code asWriter}, and populate away. The data is available
    1493     * at any time using the methods of the {@code StrBuilder}.
    1494     * </p>
    1495     * <p>
    1496     * The internal character array is shared between the builder and the writer.
    1497     * This allows you to intermix calls that append to the builder and
    1498     * write using the writer and the changes will be occur correctly.
    1499     * Note however, that no synchronization occurs, so you must perform
    1500     * all operations with the builder and the writer in one thread.
    1501     * </p>
    1502     * <p>
    1503     * The returned writer ignores the close and flush methods.
    1504     * </p>
    1505     *
    1506     * @return a writer that populates this builder
    1507     */
    1508    public Writer asWriter() {
    1509        return new StrBuilderWriter();
    1510    }
    1511
    1512    /**
    1513     * Builds a string.
    1514     *
    1515     * @return The builder as a String
    1516     * @see #toString()
    1517     */
    1518    @Override
    1519    public String build() {
    1520        return toString();
    1521    }
    1522
    1523    /**
    1524     * Gets the current size of the internal character array buffer.
    1525     *
    1526     * @return The capacity
    1527     */
    1528    public int capacity() {
    1529        return buffer.length;
    1530    }
    1531
    1532    /**
    1533     * Gets the character at the specified index.
    1534     *
    1535     * @see #setCharAt(int, char)
    1536     * @see #deleteCharAt(int)
    1537     * @param index  the index to retrieve, must be valid
    1538     * @return The character at the index
    1539     * @throws IndexOutOfBoundsException if the index is invalid
    1540     */
    1541    @Override
    1542    public char charAt(final int index) {
    1543        if (index < 0 || index >= length()) {
    1544            throw new StringIndexOutOfBoundsException(index);
    1545        }
    1546        return buffer[index];
    1547    }
    1548
    1549    /**
    1550     * Clears the string builder (convenience Collections API style method).
    1551     * <p>
    1552     * This method does not reduce the size of the internal character buffer.
    1553     * To do that, call {@code clear()} followed by {@link #minimizeCapacity()}.
    1554     * </p>
    1555     * <p>
    1556     * This method is the same as {@link #setLength(int)} called with zero
    1557     * and is provided to match the API of Collections.
    1558     * </p>
    1559     *
    1560     * @return this, to enable chaining
    1561     */
    1562    public StrBuilder clear() {
    1563        size = 0;
    1564        return this;
    1565    }
    1566
    1567    /**
    1568     * Checks if the string builder contains the specified char.
    1569     *
    1570     * @param ch  the character to find
    1571     * @return true if the builder contains the character
    1572     */
    1573    public boolean contains(final char ch) {
    1574        final char[] thisBuf = buffer;
    1575        for (int i = 0; i < this.size; i++) {
    1576            if (thisBuf[i] == ch) {
    1577                return true;
    1578            }
    1579        }
    1580        return false;
    1581    }
    1582
    1583    /**
    1584     * Tests if the string builder contains the specified string.
    1585     *
    1586     * @param str  the string to find
    1587     * @return true if the builder contains the string
    1588     */
    1589    public boolean contains(final String str) {
    1590        return indexOf(str, 0) >= 0;
    1591    }
    1592
    1593    /**
    1594     * Tests if the string builder contains a string matched using the
    1595     * specified matcher.
    1596     * <p>
    1597     * Matchers can be used to perform advanced searching behavior.
    1598     * For example you could write a matcher to search for the character
    1599     * 'a' followed by a number.
    1600     * </p>
    1601     *
    1602     * @param matcher  the matcher to use, null returns -1
    1603     * @return true if the matcher finds a match in the builder
    1604     */
    1605    public boolean contains(final StrMatcher matcher) {
    1606        return indexOf(matcher, 0) >= 0;
    1607    }
    1608
    1609    /**
    1610     * Deletes the characters between the two specified indices.
    1611     *
    1612     * @param startIndex  the start index, inclusive, must be valid
    1613     * @param endIndex  the end index, exclusive, must be valid except
    1614     *  that if too large it is treated as end of string
    1615     * @return this, to enable chaining
    1616     * @throws IndexOutOfBoundsException if the index is invalid
    1617     */
    1618    public StrBuilder delete(final int startIndex, int endIndex) {
    1619        endIndex = validateRange(startIndex, endIndex);
    1620        final int len = endIndex - startIndex;
    1621        if (len > 0) {
    1622            deleteImpl(startIndex, endIndex, len);
    1623        }
    1624        return this;
    1625    }
    1626
    1627    /**
    1628     * Deletes the character wherever it occurs in the builder.
    1629     *
    1630     * @param ch  the character to delete
    1631     * @return this, to enable chaining
    1632     */
    1633    public StrBuilder deleteAll(final char ch) {
    1634        for (int i = 0; i < size; i++) {
    1635            if (buffer[i] == ch) {
    1636                final int start = i;
    1637                while (++i < size) {
    1638                    if (buffer[i] != ch) {
    1639                        break;
    1640                    }
    1641                }
    1642                final int len = i - start;
    1643                deleteImpl(start, i, len);
    1644                i -= len;
    1645            }
    1646        }
    1647        return this;
    1648    }
    1649
    1650    /**
    1651     * Deletes the string wherever it occurs in the builder.
    1652     *
    1653     * @param str  the string to delete, null causes no action
    1654     * @return this, to enable chaining
    1655     */
    1656    public StrBuilder deleteAll(final String str) {
    1657        final int len = str == null ? 0 : str.length();
    1658        if (len > 0) {
    1659            int index = indexOf(str, 0);
    1660            while (index >= 0) {
    1661                deleteImpl(index, index + len, len);
    1662                index = indexOf(str, index);
    1663            }
    1664        }
    1665        return this;
    1666    }
    1667
    1668    /**
    1669     * Deletes all parts of the builder that the matcher matches.
    1670     * <p>
    1671     * Matchers can be used to perform advanced deletion behavior.
    1672     * For example you could write a matcher to delete all occurrences
    1673     * where the character 'a' is followed by a number.
    1674     * </p>
    1675     *
    1676     * @param matcher  the matcher to use to find the deletion, null causes no action
    1677     * @return this, to enable chaining
    1678     */
    1679    public StrBuilder deleteAll(final StrMatcher matcher) {
    1680        return replace(matcher, null, 0, size, -1);
    1681    }
    1682
    1683    /**
    1684     * Deletes the character at the specified index.
    1685     *
    1686     * @see #charAt(int)
    1687     * @see #setCharAt(int, char)
    1688     * @param index  the index to delete
    1689     * @return this, to enable chaining
    1690     * @throws IndexOutOfBoundsException if the index is invalid
    1691     */
    1692    public StrBuilder deleteCharAt(final int index) {
    1693        if (index < 0 || index >= size) {
    1694            throw new StringIndexOutOfBoundsException(index);
    1695        }
    1696        deleteImpl(index, index + 1, 1);
    1697        return this;
    1698    }
    1699
    1700    /**
    1701     * Deletes the character wherever it occurs in the builder.
    1702     *
    1703     * @param ch  the character to delete
    1704     * @return this, to enable chaining
    1705     */
    1706    public StrBuilder deleteFirst(final char ch) {
    1707        for (int i = 0; i < size; i++) {
    1708            if (buffer[i] == ch) {
    1709                deleteImpl(i, i + 1, 1);
    1710                break;
    1711            }
    1712        }
    1713        return this;
    1714    }
    1715
    1716    /**
    1717     * Deletes the string wherever it occurs in the builder.
    1718     *
    1719     * @param str  the string to delete, null causes no action
    1720     * @return this, to enable chaining
    1721     */
    1722    public StrBuilder deleteFirst(final String str) {
    1723        final int len = str == null ? 0 : str.length();
    1724        if (len > 0) {
    1725            final int index = indexOf(str, 0);
    1726            if (index >= 0) {
    1727                deleteImpl(index, index + len, len);
    1728            }
    1729        }
    1730        return this;
    1731    }
    1732
    1733    /**
    1734     * Deletes the first match within the builder using the specified matcher.
    1735     * <p>
    1736     * Matchers can be used to perform advanced deletion behavior.
    1737     * For example you could write a matcher to delete
    1738     * where the character 'a' is followed by a number.
    1739     * </p>
    1740     *
    1741     * @param matcher  the matcher to use to find the deletion, null causes no action
    1742     * @return this, to enable chaining
    1743     */
    1744    public StrBuilder deleteFirst(final StrMatcher matcher) {
    1745        return replace(matcher, null, 0, size, 1);
    1746    }
    1747
    1748    /**
    1749     * Internal method to delete a range without validation.
    1750     *
    1751     * @param startIndex  the start index, must be valid
    1752     * @param endIndex  the end index (exclusive), must be valid
    1753     * @param len  the length, must be valid
    1754     * @throws IndexOutOfBoundsException if any index is invalid
    1755     */
    1756    private void deleteImpl(final int startIndex, final int endIndex, final int len) {
    1757        System.arraycopy(buffer, endIndex, buffer, startIndex, size - endIndex);
    1758        size -= len;
    1759    }
    1760
    1761    /**
    1762     * Tests whether this builder ends with the specified string.
    1763     * <p>
    1764     * Note that this method handles null input quietly, unlike String.
    1765     * </p>
    1766     *
    1767     * @param str  the string to search for, null returns false
    1768     * @return true if the builder ends with the string
    1769     */
    1770    public boolean endsWith(final String str) {
    1771        if (str == null) {
    1772            return false;
    1773        }
    1774        final int len = str.length();
    1775        if (len == 0) {
    1776            return true;
    1777        }
    1778        if (len > size) {
    1779            return false;
    1780        }
    1781        int pos = size - len;
    1782        for (int i = 0; i < len; i++, pos++) {
    1783            if (buffer[pos] != str.charAt(i)) {
    1784                return false;
    1785            }
    1786        }
    1787        return true;
    1788    }
    1789
    1790    /**
    1791     * Tests the capacity and ensures that it is at least the size specified.
    1792     *
    1793     * @param capacity  the capacity to ensure
    1794     * @return this, to enable chaining
    1795     */
    1796    public StrBuilder ensureCapacity(final int capacity) {
    1797        if (capacity > buffer.length) {
    1798            final char[] old = buffer;
    1799            buffer = new char[capacity * 2];
    1800            System.arraycopy(old, 0, buffer, 0, size);
    1801        }
    1802        return this;
    1803    }
    1804
    1805    /**
    1806     * Tests the contents of this builder against another to see if they
    1807     * contain the same character content.
    1808     *
    1809     * @param obj  the object to check, null returns false
    1810     * @return true if the builders contain the same characters in the same order
    1811     */
    1812    @Override
    1813    public boolean equals(final Object obj) {
    1814        return obj instanceof StrBuilder
    1815                && equals((StrBuilder) obj);
    1816    }
    1817
    1818    /**
    1819     * Tests the contents of this builder against another to see if they
    1820     * contain the same character content.
    1821     *
    1822     * @param other  the object to check, null returns false
    1823     * @return true if the builders contain the same characters in the same order
    1824     */
    1825    public boolean equals(final StrBuilder other) {
    1826        if (this == other) {
    1827            return true;
    1828        }
    1829        if (other == null) {
    1830            return false;
    1831        }
    1832        if (this.size != other.size) {
    1833            return false;
    1834        }
    1835        final char[] thisBuf = this.buffer;
    1836        final char[] otherBuf = other.buffer;
    1837        for (int i = size - 1; i >= 0; i--) {
    1838            if (thisBuf[i] != otherBuf[i]) {
    1839                return false;
    1840            }
    1841        }
    1842        return true;
    1843    }
    1844
    1845    /**
    1846     * Tests the contents of this builder against another to see if they
    1847     * contain the same character content ignoring case.
    1848     *
    1849     * @param other  the object to check, null returns false
    1850     * @return true if the builders contain the same characters in the same order
    1851     */
    1852    public boolean equalsIgnoreCase(final StrBuilder other) {
    1853        if (this == other) {
    1854            return true;
    1855        }
    1856        if (this.size != other.size) {
    1857            return false;
    1858        }
    1859        final char[] thisBuf = this.buffer;
    1860        final char[] otherBuf = other.buffer;
    1861        for (int i = size - 1; i >= 0; i--) {
    1862            final char c1 = thisBuf[i];
    1863            final char c2 = otherBuf[i];
    1864            if (c1 != c2 && Character.toUpperCase(c1) != Character.toUpperCase(c2)) {
    1865                return false;
    1866            }
    1867        }
    1868        return true;
    1869    }
    1870
    1871    /**
    1872     * Copies the character array into the specified array.
    1873     *
    1874     * @param destination  the destination array, null will cause an array to be created
    1875     * @return The input array, unless that was null or too small
    1876     */
    1877    public char[] getChars(char[] destination) {
    1878        final int len = length();
    1879        if (destination == null || destination.length < len) {
    1880            destination = new char[len];
    1881        }
    1882        System.arraycopy(buffer, 0, destination, 0, len);
    1883        return destination;
    1884    }
    1885
    1886    /**
    1887     * Copies the character array into the specified array.
    1888     *
    1889     * @param startIndex  first index to copy, inclusive, must be valid
    1890     * @param endIndex  last index, exclusive, must be valid
    1891     * @param destination  the destination array, must not be null or too small
    1892     * @param destinationIndex  the index to start copying in destination
    1893     * @throws NullPointerException if the array is null
    1894     * @throws IndexOutOfBoundsException if any index is invalid
    1895     */
    1896    public void getChars(final int startIndex,
    1897                         final int endIndex,
    1898                         final char[] destination,
    1899                         final int destinationIndex) {
    1900        if (startIndex < 0) {
    1901            throw new StringIndexOutOfBoundsException(startIndex);
    1902        }
    1903        if (endIndex < 0 || endIndex > length()) {
    1904            throw new StringIndexOutOfBoundsException(endIndex);
    1905        }
    1906        if (startIndex > endIndex) {
    1907            throw new StringIndexOutOfBoundsException("end < start");
    1908        }
    1909        System.arraycopy(buffer, startIndex, destination, destinationIndex, endIndex - startIndex);
    1910    }
    1911
    1912    /**
    1913     * Gets the text to be appended when a new line is added.
    1914     *
    1915     * @return The new line text, null means use system default
    1916     */
    1917    public String getNewLineText() {
    1918        return newLine;
    1919    }
    1920
    1921    /**
    1922     * Gets the text to be appended when null is added.
    1923     *
    1924     * @return The null text, null means no append
    1925     */
    1926    public String getNullText() {
    1927        return nullText;
    1928    }
    1929
    1930    /**
    1931     * Gets a suitable hash code for this builder.
    1932     *
    1933     * @return a hash code
    1934     */
    1935    @Override
    1936    public int hashCode() {
    1937        final char[] buf = buffer;
    1938        int hash = 0;
    1939        for (int i = size - 1; i >= 0; i--) {
    1940            hash = 31 * hash + buf[i];
    1941        }
    1942        return hash;
    1943    }
    1944
    1945    /**
    1946     * Searches the string builder to find the first reference to the specified char.
    1947     *
    1948     * @param ch  the character to find
    1949     * @return The first index of the character, or -1 if not found
    1950     */
    1951    public int indexOf(final char ch) {
    1952        return indexOf(ch, 0);
    1953    }
    1954
    1955    /**
    1956     * Searches the string builder to find the first reference to the specified char.
    1957     *
    1958     * @param ch  the character to find
    1959     * @param startIndex  the index to start at, invalid index rounded to edge
    1960     * @return The first index of the character, or -1 if not found
    1961     */
    1962    public int indexOf(final char ch, int startIndex) {
    1963        startIndex = Math.max(startIndex, 0);
    1964        if (startIndex >= size) {
    1965            return -1;
    1966        }
    1967        final char[] thisBuf = buffer;
    1968        for (int i = startIndex; i < size; i++) {
    1969            if (thisBuf[i] == ch) {
    1970                return i;
    1971            }
    1972        }
    1973        return -1;
    1974    }
    1975
    1976    /**
    1977     * Searches the string builder to find the first reference to the specified string.
    1978     * <p>
    1979     * Note that a null input string will return -1, whereas the JDK throws an exception.
    1980     * </p>
    1981     *
    1982     * @param str  the string to find, null returns -1
    1983     * @return The first index of the string, or -1 if not found
    1984     */
    1985    public int indexOf(final String str) {
    1986        return indexOf(str, 0);
    1987    }
    1988
    1989    /**
    1990     * Searches the string builder to find the first reference to the specified
    1991     * string starting searching from the given index.
    1992     * <p>
    1993     * Note that a null input string will return -1, whereas the JDK throws an exception.
    1994     * </p>
    1995     *
    1996     * @param str  the string to find, null returns -1
    1997     * @param startIndex  the index to start at, invalid index rounded to edge
    1998     * @return The first index of the string, or -1 if not found
    1999     */
    2000    public int indexOf(final String str, int startIndex) {
    2001        startIndex = Math.max(startIndex, 0);
    2002        if (str == null || startIndex >= size) {
    2003            return -1;
    2004        }
    2005        final int strLen = str.length();
    2006        if (strLen == 1) {
    2007            return indexOf(str.charAt(0), startIndex);
    2008        }
    2009        if (strLen == 0) {
    2010            return startIndex;
    2011        }
    2012        if (strLen > size) {
    2013            return -1;
    2014        }
    2015        final char[] thisBuf = buffer;
    2016        final int len = size - strLen + 1;
    2017        outer:
    2018        for (int i = startIndex; i < len; i++) {
    2019            for (int j = 0; j < strLen; j++) {
    2020                if (str.charAt(j) != thisBuf[i + j]) {
    2021                    continue outer;
    2022                }
    2023            }
    2024            return i;
    2025        }
    2026        return -1;
    2027    }
    2028
    2029    /**
    2030     * Searches the string builder using the matcher to find the first match.
    2031     * <p>
    2032     * Matchers can be used to perform advanced searching behavior.
    2033     * For example you could write a matcher to find the character 'a'
    2034     * followed by a number.
    2035     * </p>
    2036     *
    2037     * @param matcher  the matcher to use, null returns -1
    2038     * @return The first index matched, or -1 if not found
    2039     */
    2040    public int indexOf(final StrMatcher matcher) {
    2041        return indexOf(matcher, 0);
    2042    }
    2043
    2044    /**
    2045     * Searches the string builder using the matcher to find the first
    2046     * match searching from the given index.
    2047     * <p>
    2048     * Matchers can be used to perform advanced searching behavior.
    2049     * For example you could write a matcher to find the character 'a'
    2050     * followed by a number.
    2051     * </p>
    2052     *
    2053     * @param matcher  the matcher to use, null returns -1
    2054     * @param startIndex  the index to start at, invalid index rounded to edge
    2055     * @return The first index matched, or -1 if not found
    2056     */
    2057    public int indexOf(final StrMatcher matcher, int startIndex) {
    2058        startIndex = Math.max(startIndex, 0);
    2059        if (matcher == null || startIndex >= size) {
    2060            return -1;
    2061        }
    2062        final int len = size;
    2063        final char[] buf = buffer;
    2064        for (int i = startIndex; i < len; i++) {
    2065            if (matcher.isMatch(buf, i, startIndex, len) > 0) {
    2066                return i;
    2067            }
    2068        }
    2069        return -1;
    2070    }
    2071
    2072    /**
    2073     * Inserts the value into this builder.
    2074     *
    2075     * @param index  the index to add at, must be valid
    2076     * @param value  the value to insert
    2077     * @return this, to enable chaining
    2078     * @throws IndexOutOfBoundsException if the index is invalid
    2079     */
    2080    public StrBuilder insert(int index, final boolean value) {
    2081        validateIndex(index);
    2082        if (value) {
    2083            ensureCapacity(size + 4);
    2084            System.arraycopy(buffer, index, buffer, index + 4, size - index);
    2085            buffer[index++] = 't';
    2086            buffer[index++] = 'r';
    2087            buffer[index++] = 'u';
    2088            buffer[index] = 'e';
    2089            size += 4;
    2090        } else {
    2091            ensureCapacity(size + 5);
    2092            System.arraycopy(buffer, index, buffer, index + 5, size - index);
    2093            buffer[index++] = 'f';
    2094            buffer[index++] = 'a';
    2095            buffer[index++] = 'l';
    2096            buffer[index++] = 's';
    2097            buffer[index] = 'e';
    2098            size += 5;
    2099        }
    2100        return this;
    2101    }
    2102
    2103    /**
    2104     * Inserts the value into this builder.
    2105     *
    2106     * @param index  the index to add at, must be valid
    2107     * @param value  the value to insert
    2108     * @return this, to enable chaining
    2109     * @throws IndexOutOfBoundsException if the index is invalid
    2110     */
    2111    public StrBuilder insert(final int index, final char value) {
    2112        validateIndex(index);
    2113        ensureCapacity(size + 1);
    2114        System.arraycopy(buffer, index, buffer, index + 1, size - index);
    2115        buffer[index] = value;
    2116        size++;
    2117        return this;
    2118    }
    2119
    2120    /**
    2121     * Inserts the character array into this builder.
    2122     * Inserting null will use the stored null text value.
    2123     *
    2124     * @param index  the index to add at, must be valid
    2125     * @param chars  the char array to insert
    2126     * @return this, to enable chaining
    2127     * @throws IndexOutOfBoundsException if the index is invalid
    2128     */
    2129    public StrBuilder insert(final int index, final char[] chars) {
    2130        validateIndex(index);
    2131        if (chars == null) {
    2132            return insert(index, nullText);
    2133        }
    2134        final int len = chars.length;
    2135        if (len > 0) {
    2136            ensureCapacity(size + len);
    2137            System.arraycopy(buffer, index, buffer, index + len, size - index);
    2138            System.arraycopy(chars, 0, buffer, index, len);
    2139            size += len;
    2140        }
    2141        return this;
    2142    }
    2143
    2144    /**
    2145     * Inserts part of the character array into this builder.
    2146     * Inserting null will use the stored null text value.
    2147     *
    2148     * @param index  the index to add at, must be valid
    2149     * @param chars  the char array to insert
    2150     * @param offset  the offset into the character array to start at, must be valid
    2151     * @param length  the length of the character array part to copy, must be positive
    2152     * @return this, to enable chaining
    2153     * @throws IndexOutOfBoundsException if any index is invalid
    2154     */
    2155    public StrBuilder insert(final int index, final char[] chars, final int offset, final int length) {
    2156        validateIndex(index);
    2157        if (chars == null) {
    2158            return insert(index, nullText);
    2159        }
    2160        if (offset < 0 || offset > chars.length) {
    2161            throw new StringIndexOutOfBoundsException("Invalid offset: " + offset);
    2162        }
    2163        if (length < 0 || offset + length > chars.length) {
    2164            throw new StringIndexOutOfBoundsException("Invalid length: " + length);
    2165        }
    2166        if (length > 0) {
    2167            ensureCapacity(size + length);
    2168            System.arraycopy(buffer, index, buffer, index + length, size - index);
    2169            System.arraycopy(chars, offset, buffer, index, length);
    2170            size += length;
    2171        }
    2172        return this;
    2173    }
    2174
    2175    /**
    2176     * Inserts the value into this builder.
    2177     *
    2178     * @param index  the index to add at, must be valid
    2179     * @param value  the value to insert
    2180     * @return this, to enable chaining
    2181     * @throws IndexOutOfBoundsException if the index is invalid
    2182     */
    2183    public StrBuilder insert(final int index, final double value) {
    2184        return insert(index, String.valueOf(value));
    2185    }
    2186
    2187    /**
    2188     * Inserts the value into this builder.
    2189     *
    2190     * @param index  the index to add at, must be valid
    2191     * @param value  the value to insert
    2192     * @return this, to enable chaining
    2193     * @throws IndexOutOfBoundsException if the index is invalid
    2194     */
    2195    public StrBuilder insert(final int index, final float value) {
    2196        return insert(index, String.valueOf(value));
    2197    }
    2198
    2199    /**
    2200     * Inserts the value into this builder.
    2201     *
    2202     * @param index  the index to add at, must be valid
    2203     * @param value  the value to insert
    2204     * @return this, to enable chaining
    2205     * @throws IndexOutOfBoundsException if the index is invalid
    2206     */
    2207    public StrBuilder insert(final int index, final int value) {
    2208        return insert(index, String.valueOf(value));
    2209    }
    2210
    2211    /**
    2212     * Inserts the value into this builder.
    2213     *
    2214     * @param index  the index to add at, must be valid
    2215     * @param value  the value to insert
    2216     * @return this, to enable chaining
    2217     * @throws IndexOutOfBoundsException if the index is invalid
    2218     */
    2219    public StrBuilder insert(final int index, final long value) {
    2220        return insert(index, String.valueOf(value));
    2221    }
    2222
    2223    /**
    2224     * Inserts the string representation of an object into this builder.
    2225     * Inserting null will use the stored null text value.
    2226     *
    2227     * @param index  the index to add at, must be valid
    2228     * @param obj  the object to insert
    2229     * @return this, to enable chaining
    2230     * @throws IndexOutOfBoundsException if the index is invalid
    2231     */
    2232    public StrBuilder insert(final int index, final Object obj) {
    2233        if (obj == null) {
    2234            return insert(index, nullText);
    2235        }
    2236        return insert(index, obj.toString());
    2237    }
    2238
    2239    /**
    2240     * Inserts the string into this builder.
    2241     * Inserting null will use the stored null text value.
    2242     *
    2243     * @param index  the index to add at, must be valid
    2244     * @param str  the string to insert
    2245     * @return this, to enable chaining
    2246     * @throws IndexOutOfBoundsException if the index is invalid
    2247     */
    2248    public StrBuilder insert(final int index, String str) {
    2249        validateIndex(index);
    2250        if (str == null) {
    2251            str = nullText;
    2252        }
    2253        if (str != null) {
    2254            final int strLen = str.length();
    2255            if (strLen > 0) {
    2256                final int newSize = size + strLen;
    2257                ensureCapacity(newSize);
    2258                System.arraycopy(buffer, index, buffer, index + strLen, size - index);
    2259                size = newSize;
    2260                str.getChars(0, strLen, buffer, index);
    2261            }
    2262        }
    2263        return this;
    2264    }
    2265
    2266    /**
    2267     * Tests if the string builder is empty (convenience Collections API style method).
    2268     * <p>
    2269     * This method is the same as checking {@link #length()} and is provided to match the
    2270     * API of Collections.
    2271     * </p>
    2272     *
    2273     * @return {@code true} if the size is {@code 0}.
    2274     */
    2275    public boolean isEmpty() {
    2276        return size == 0;
    2277    }
    2278
    2279    /**
    2280     * Tests if the string builder is not empty (convenience Collections API style method).
    2281     * <p>
    2282     * This method is the same as checking {@link #length()} and is provided to match the
    2283     * API of Collections.
    2284     * </p>
    2285     *
    2286     * @return {@code true} if the size is greater than {@code 0}.
    2287     * @since 1.10.0
    2288     */
    2289    public boolean isNotEmpty() {
    2290        return size > 0;
    2291    }
    2292
    2293    /**
    2294     * Searches the string builder to find the last reference to the specified char.
    2295     *
    2296     * @param ch  the character to find
    2297     * @return The last index of the character, or -1 if not found
    2298     */
    2299    public int lastIndexOf(final char ch) {
    2300        return lastIndexOf(ch, size - 1);
    2301    }
    2302
    2303    /**
    2304     * Searches the string builder to find the last reference to the specified char.
    2305     *
    2306     * @param ch  the character to find
    2307     * @param startIndex  the index to start at, invalid index rounded to edge
    2308     * @return The last index of the character, or -1 if not found
    2309     */
    2310    public int lastIndexOf(final char ch, int startIndex) {
    2311        startIndex = startIndex >= size ? size - 1 : startIndex;
    2312        if (startIndex < 0) {
    2313            return -1;
    2314        }
    2315        for (int i = startIndex; i >= 0; i--) {
    2316            if (buffer[i] == ch) {
    2317                return i;
    2318            }
    2319        }
    2320        return -1;
    2321    }
    2322
    2323    /**
    2324     * Searches the string builder to find the last reference to the specified string.
    2325     * <p>
    2326     * Note that a null input string will return -1, whereas the JDK throws an exception.
    2327     * </p>
    2328     *
    2329     * @param str  the string to find, null returns -1
    2330     * @return The last index of the string, or -1 if not found
    2331     */
    2332    public int lastIndexOf(final String str) {
    2333        return lastIndexOf(str, size - 1);
    2334    }
    2335
    2336    /**
    2337     * Searches the string builder to find the last reference to the specified
    2338     * string starting searching from the given index.
    2339     * <p>
    2340     * Note that a null input string will return -1, whereas the JDK throws an exception.
    2341     * </p>
    2342     *
    2343     * @param str  the string to find, null returns -1
    2344     * @param startIndex  the index to start at, invalid index rounded to edge
    2345     * @return The last index of the string, or -1 if not found
    2346     */
    2347    public int lastIndexOf(final String str, int startIndex) {
    2348        startIndex = startIndex >= size ? size - 1 : startIndex;
    2349        if (str == null || startIndex < 0) {
    2350            return -1;
    2351        }
    2352        final int strLen = str.length();
    2353        if (strLen > 0 && strLen <= size) {
    2354            if (strLen == 1) {
    2355                return lastIndexOf(str.charAt(0), startIndex);
    2356            }
    2357
    2358            outer:
    2359            for (int i = startIndex - strLen + 1; i >= 0; i--) {
    2360                for (int j = 0; j < strLen; j++) {
    2361                    if (str.charAt(j) != buffer[i + j]) {
    2362                        continue outer;
    2363                    }
    2364                }
    2365                return i;
    2366            }
    2367
    2368        } else if (strLen == 0) {
    2369            return startIndex;
    2370        }
    2371        return -1;
    2372    }
    2373
    2374    /**
    2375     * Searches the string builder using the matcher to find the last match.
    2376     * <p>
    2377     * Matchers can be used to perform advanced searching behavior.
    2378     * For example you could write a matcher to find the character 'a'
    2379     * followed by a number.
    2380     * </p>
    2381     *
    2382     * @param matcher  the matcher to use, null returns -1
    2383     * @return The last index matched, or -1 if not found
    2384     */
    2385    public int lastIndexOf(final StrMatcher matcher) {
    2386        return lastIndexOf(matcher, size);
    2387    }
    2388
    2389    /**
    2390     * Searches the string builder using the matcher to find the last
    2391     * match searching from the given index.
    2392     * <p>
    2393     * Matchers can be used to perform advanced searching behavior.
    2394     * For example you could write a matcher to find the character 'a'
    2395     * followed by a number.
    2396     * </p>
    2397     *
    2398     * @param matcher  the matcher to use, null returns -1
    2399     * @param startIndex  the index to start at, invalid index rounded to edge
    2400     * @return The last index matched, or -1 if not found
    2401     */
    2402    public int lastIndexOf(final StrMatcher matcher, int startIndex) {
    2403        startIndex = startIndex >= size ? size - 1 : startIndex;
    2404        if (matcher == null || startIndex < 0) {
    2405            return -1;
    2406        }
    2407        final char[] buf = buffer;
    2408        final int endIndex = startIndex + 1;
    2409        for (int i = startIndex; i >= 0; i--) {
    2410            if (matcher.isMatch(buf, i, 0, endIndex) > 0) {
    2411                return i;
    2412            }
    2413        }
    2414        return -1;
    2415    }
    2416
    2417    /**
    2418     * Extracts the leftmost characters from the string builder without
    2419     * throwing an exception.
    2420     * <p>
    2421     * This method extracts the left {@code length} characters from
    2422     * the builder. If this many characters are not available, the whole
    2423     * builder is returned. Thus the returned string may be shorter than the
    2424     * length requested.
    2425     * </p>
    2426     *
    2427     * @param length  the number of characters to extract, negative returns empty string
    2428     * @return The new string
    2429     */
    2430    public String leftString(final int length) {
    2431        if (length <= 0) {
    2432            return StringUtils.EMPTY;
    2433        }
    2434        if (length >= size) {
    2435            return new String(buffer, 0, size);
    2436        }
    2437        return new String(buffer, 0, length);
    2438    }
    2439
    2440    /**
    2441     * Gets the length of the string builder.
    2442     *
    2443     * @return The length
    2444     */
    2445    @Override
    2446    public int length() {
    2447        return size;
    2448    }
    2449
    2450    /**
    2451     * Extracts some characters from the middle of the string builder without
    2452     * throwing an exception.
    2453     * <p>
    2454     * This method extracts {@code length} characters from the builder
    2455     * at the specified index.
    2456     * If the index is negative it is treated as zero.
    2457     * If the index is greater than the builder size, it is treated as the builder size.
    2458     * If the length is negative, the empty string is returned.
    2459     * If insufficient characters are available in the builder, as much as possible is returned.
    2460     * Thus the returned string may be shorter than the length requested.
    2461     * </p>
    2462     *
    2463     * @param index  the index to start at, negative means zero
    2464     * @param length  the number of characters to extract, negative returns empty string
    2465     * @return The new string
    2466     */
    2467    public String midString(int index, final int length) {
    2468        if (index < 0) {
    2469            index = 0;
    2470        }
    2471        if (length <= 0 || index >= size) {
    2472            return StringUtils.EMPTY;
    2473        }
    2474        if (size <= index + length) {
    2475            return new String(buffer, index, size - index);
    2476        }
    2477        return new String(buffer, index, length);
    2478    }
    2479
    2480    /**
    2481     * Minimizes the capacity to the actual length of the string.
    2482     *
    2483     * @return this, to enable chaining
    2484     */
    2485    public StrBuilder minimizeCapacity() {
    2486        if (buffer.length > length()) {
    2487            final char[] old = buffer;
    2488            buffer = new char[length()];
    2489            System.arraycopy(old, 0, buffer, 0, size);
    2490        }
    2491        return this;
    2492    }
    2493
    2494    /**
    2495     * If possible, reads chars from the provided {@link Readable} directly into underlying
    2496     * character buffer without making extra copies.
    2497     *
    2498     * @param readable  object to read from
    2499     * @return The number of characters read
    2500     * @throws IOException if an I/O error occurs.
    2501     *
    2502     * @see #appendTo(Appendable)
    2503     */
    2504    public int readFrom(final Readable readable) throws IOException {
    2505        final int oldSize = size;
    2506        if (readable instanceof Reader) {
    2507            final Reader r = (Reader) readable;
    2508            ensureCapacity(size + 1);
    2509            int read;
    2510            while ((read = r.read(buffer, size, buffer.length - size)) != -1) {
    2511                size += read;
    2512                ensureCapacity(size + 1);
    2513            }
    2514        } else if (readable instanceof CharBuffer) {
    2515            final CharBuffer cb = (CharBuffer) readable;
    2516            final int remaining = cb.remaining();
    2517            ensureCapacity(size + remaining);
    2518            cb.get(buffer, size, remaining);
    2519            size += remaining;
    2520        } else {
    2521            while (true) {
    2522                ensureCapacity(size + 1);
    2523                final CharBuffer buf = CharBuffer.wrap(buffer, size, buffer.length - size);
    2524                final int read = readable.read(buf);
    2525                if (read == -1) {
    2526                    break;
    2527                }
    2528                size += read;
    2529            }
    2530        }
    2531        return size - oldSize;
    2532    }
    2533
    2534    /**
    2535     * Replaces a portion of the string builder with another string.
    2536     * The length of the inserted string does not have to match the removed length.
    2537     *
    2538     * @param startIndex  the start index, inclusive, must be valid
    2539     * @param endIndex  the end index, exclusive, must be valid except
    2540     *  that if too large it is treated as end of string
    2541     * @param replaceStr  the string to replace with, null means delete range
    2542     * @return this, to enable chaining
    2543     * @throws IndexOutOfBoundsException if the index is invalid
    2544     */
    2545    public StrBuilder replace(final int startIndex, int endIndex, final String replaceStr) {
    2546        endIndex = validateRange(startIndex, endIndex);
    2547        final int insertLen = replaceStr == null ? 0 : replaceStr.length();
    2548        replaceImpl(startIndex, endIndex, endIndex - startIndex, replaceStr, insertLen);
    2549        return this;
    2550    }
    2551
    2552    /**
    2553     * Advanced search and replaces within the builder using a matcher.
    2554     * <p>
    2555     * Matchers can be used to perform advanced behavior.
    2556     * For example you could write a matcher to delete all occurrences
    2557     * where the character 'a' is followed by a number.
    2558     * </p>
    2559     *
    2560     * @param matcher  the matcher to use to find the deletion, null causes no action
    2561     * @param replaceStr  the string to replace the match with, null is a delete
    2562     * @param startIndex  the start index, inclusive, must be valid
    2563     * @param endIndex  the end index, exclusive, must be valid except
    2564     *  that if too large it is treated as end of string
    2565     * @param replaceCount  the number of times to replace, -1 for replace all
    2566     * @return this, to enable chaining
    2567     * @throws IndexOutOfBoundsException if start index is invalid
    2568     */
    2569    public StrBuilder replace(
    2570            final StrMatcher matcher, final String replaceStr,
    2571            final int startIndex, int endIndex, final int replaceCount) {
    2572        endIndex = validateRange(startIndex, endIndex);
    2573        return replaceImpl(matcher, replaceStr, startIndex, endIndex, replaceCount);
    2574    }
    2575
    2576    /**
    2577     * Replaces the search character with the replace character
    2578     * throughout the builder.
    2579     *
    2580     * @param search  the search character
    2581     * @param replace  the replace character
    2582     * @return this, to enable chaining
    2583     */
    2584    public StrBuilder replaceAll(final char search, final char replace) {
    2585        if (search != replace) {
    2586            for (int i = 0; i < size; i++) {
    2587                if (buffer[i] == search) {
    2588                    buffer[i] = replace;
    2589                }
    2590            }
    2591        }
    2592        return this;
    2593    }
    2594
    2595    /**
    2596     * Replaces the search string with the replace string throughout the builder.
    2597     *
    2598     * @param searchStr  the search string, null causes no action to occur
    2599     * @param replaceStr  the replace string, null is equivalent to an empty string
    2600     * @return this, to enable chaining
    2601     */
    2602    public StrBuilder replaceAll(final String searchStr, final String replaceStr) {
    2603        final int searchLen = searchStr == null ? 0 : searchStr.length();
    2604        if (searchLen > 0) {
    2605            final int replaceLen = replaceStr == null ? 0 : replaceStr.length();
    2606            int index = indexOf(searchStr, 0);
    2607            while (index >= 0) {
    2608                replaceImpl(index, index + searchLen, searchLen, replaceStr, replaceLen);
    2609                index = indexOf(searchStr, index + replaceLen);
    2610            }
    2611        }
    2612        return this;
    2613    }
    2614
    2615    /**
    2616     * Replaces all matches within the builder with the replace string.
    2617     * <p>
    2618     * Matchers can be used to perform advanced replace behavior.
    2619     * For example you could write a matcher to replace all occurrences
    2620     * where the character 'a' is followed by a number.
    2621     * </p>
    2622     *
    2623     * @param matcher  the matcher to use to find the deletion, null causes no action
    2624     * @param replaceStr  the replace string, null is equivalent to an empty string
    2625     * @return this, to enable chaining
    2626     */
    2627    public StrBuilder replaceAll(final StrMatcher matcher, final String replaceStr) {
    2628        return replace(matcher, replaceStr, 0, size, -1);
    2629    }
    2630
    2631    /**
    2632     * Replaces the first instance of the search character with the
    2633     * replace character in the builder.
    2634     *
    2635     * @param search  the search character
    2636     * @param replace  the replace character
    2637     * @return this, to enable chaining
    2638     */
    2639    public StrBuilder replaceFirst(final char search, final char replace) {
    2640        if (search != replace) {
    2641            for (int i = 0; i < size; i++) {
    2642                if (buffer[i] == search) {
    2643                    buffer[i] = replace;
    2644                    break;
    2645                }
    2646            }
    2647        }
    2648        return this;
    2649    }
    2650
    2651    /**
    2652     * Replaces the first instance of the search string with the replace string.
    2653     *
    2654     * @param searchStr  the search string, null causes no action to occur
    2655     * @param replaceStr  the replace string, null is equivalent to an empty string
    2656     * @return this, to enable chaining
    2657     */
    2658    public StrBuilder replaceFirst(final String searchStr, final String replaceStr) {
    2659        final int searchLen = searchStr == null ? 0 : searchStr.length();
    2660        if (searchLen > 0) {
    2661            final int index = indexOf(searchStr, 0);
    2662            if (index >= 0) {
    2663                final int replaceLen = replaceStr == null ? 0 : replaceStr.length();
    2664                replaceImpl(index, index + searchLen, searchLen, replaceStr, replaceLen);
    2665            }
    2666        }
    2667        return this;
    2668    }
    2669
    2670    /**
    2671     * Replaces the first match within the builder with the replace string.
    2672     * <p>
    2673     * Matchers can be used to perform advanced replace behavior.
    2674     * For example you could write a matcher to replace
    2675     * where the character 'a' is followed by a number.
    2676     * </p>
    2677     *
    2678     * @param matcher  the matcher to use to find the deletion, null causes no action
    2679     * @param replaceStr  the replace string, null is equivalent to an empty string
    2680     * @return this, to enable chaining
    2681     */
    2682    public StrBuilder replaceFirst(final StrMatcher matcher, final String replaceStr) {
    2683        return replace(matcher, replaceStr, 0, size, 1);
    2684    }
    2685
    2686    /**
    2687     * Internal method to delete a range without validation.
    2688     *
    2689     * @param startIndex  the start index, must be valid
    2690     * @param endIndex  the end index (exclusive), must be valid
    2691     * @param removeLen  the length to remove (endIndex - startIndex), must be valid
    2692     * @param insertStr  the string to replace with, null means delete range
    2693     * @param insertLen  the length of the insert string, must be valid
    2694     * @throws IndexOutOfBoundsException if any index is invalid
    2695     */
    2696    private void replaceImpl(final int startIndex,
    2697                             final int endIndex,
    2698                             final int removeLen,
    2699                             final String insertStr,
    2700                             final int insertLen) {
    2701        final int newSize = size - removeLen + insertLen;
    2702        if (insertLen != removeLen) {
    2703            ensureCapacity(newSize);
    2704            System.arraycopy(buffer, endIndex, buffer, startIndex + insertLen, size - endIndex);
    2705            size = newSize;
    2706        }
    2707        if (insertLen > 0) {
    2708            insertStr.getChars(0, insertLen, buffer, startIndex);
    2709        }
    2710    }
    2711
    2712    /**
    2713     * Replaces within the builder using a matcher.
    2714     * <p>
    2715     * Matchers can be used to perform advanced behavior.
    2716     * For example you could write a matcher to delete all occurrences
    2717     * where the character 'a' is followed by a number.
    2718     * </p>
    2719     *
    2720     * @param matcher  the matcher to use to find the deletion, null causes no action
    2721     * @param replaceStr  the string to replace the match with, null is a delete
    2722     * @param from  the start index, must be valid
    2723     * @param to  the end index (exclusive), must be valid
    2724     * @param replaceCount  the number of times to replace, -1 for replace all
    2725     * @return this, to enable chaining
    2726     * @throws IndexOutOfBoundsException if any index is invalid
    2727     */
    2728    private StrBuilder replaceImpl(
    2729            final StrMatcher matcher, final String replaceStr,
    2730            final int from, int to, int replaceCount) {
    2731        if (matcher == null || size == 0) {
    2732            return this;
    2733        }
    2734        final int replaceLen = replaceStr == null ? 0 : replaceStr.length();
    2735        for (int i = from; i < to && replaceCount != 0; i++) {
    2736            final char[] buf = buffer;
    2737            final int removeLen = matcher.isMatch(buf, i, from, to);
    2738            if (removeLen > 0) {
    2739                replaceImpl(i, i + removeLen, removeLen, replaceStr, replaceLen);
    2740                to = to - removeLen + replaceLen;
    2741                i = i + replaceLen - 1;
    2742                if (replaceCount > 0) {
    2743                    replaceCount--;
    2744                }
    2745            }
    2746        }
    2747        return this;
    2748    }
    2749
    2750    /**
    2751     * Reverses the string builder placing each character in the opposite index.
    2752     *
    2753     * @return this, to enable chaining
    2754     */
    2755    public StrBuilder reverse() {
    2756        if (size == 0) {
    2757            return this;
    2758        }
    2759
    2760        final int half = size / 2;
    2761        final char[] buf = buffer;
    2762        for (int leftIdx = 0, rightIdx = size - 1; leftIdx < half; leftIdx++, rightIdx--) {
    2763            final char swap = buf[leftIdx];
    2764            buf[leftIdx] = buf[rightIdx];
    2765            buf[rightIdx] = swap;
    2766        }
    2767        return this;
    2768    }
    2769
    2770    /**
    2771     * Extracts the rightmost characters from the string builder without
    2772     * throwing an exception.
    2773     * <p>
    2774     * This method extracts the right {@code length} characters from
    2775     * the builder. If this many characters are not available, the whole
    2776     * builder is returned. Thus the returned string may be shorter than the
    2777     * length requested.
    2778     * </p>
    2779     *
    2780     * @param length  the number of characters to extract, negative returns empty string
    2781     * @return The new string
    2782     */
    2783    public String rightString(final int length) {
    2784        if (length <= 0) {
    2785            return StringUtils.EMPTY;
    2786        }
    2787        if (length >= size) {
    2788            return new String(buffer, 0, size);
    2789        }
    2790        return new String(buffer, size - length, length);
    2791    }
    2792
    2793    /**
    2794     * Sets the character at the specified index.
    2795     *
    2796     * @see #charAt(int)
    2797     * @see #deleteCharAt(int)
    2798     * @param index  the index to set
    2799     * @param ch  the new character
    2800     * @return this, to enable chaining
    2801     * @throws IndexOutOfBoundsException if the index is invalid
    2802     */
    2803    public StrBuilder setCharAt(final int index, final char ch) {
    2804        if (index < 0 || index >= length()) {
    2805            throw new StringIndexOutOfBoundsException(index);
    2806        }
    2807        buffer[index] = ch;
    2808        return this;
    2809    }
    2810
    2811    /**
    2812     * Updates the length of the builder by either dropping the last characters
    2813     * or adding filler of Unicode zero.
    2814     *
    2815     * @param length  the length to set to, must be zero or positive
    2816     * @return this, to enable chaining
    2817     * @throws IndexOutOfBoundsException if the length is negative
    2818     */
    2819    public StrBuilder setLength(final int length) {
    2820        if (length < 0) {
    2821            throw new StringIndexOutOfBoundsException(length);
    2822        }
    2823        if (length < size) {
    2824            size = length;
    2825        } else if (length > size) {
    2826            ensureCapacity(length);
    2827            final int oldEnd = size;
    2828            size = length;
    2829            for (int i = oldEnd; i < length; i++) {
    2830                buffer[i] = '\0';
    2831            }
    2832        }
    2833        return this;
    2834    }
    2835
    2836    /**
    2837     * Sets the text to be appended when a new line is added.
    2838     *
    2839     * @param newLine  the new line text, null means use system default
    2840     * @return this, to enable chaining
    2841     */
    2842    public StrBuilder setNewLineText(final String newLine) {
    2843        this.newLine = newLine;
    2844        return this;
    2845    }
    2846
    2847    /**
    2848     * Sets the text to be appended when null is added.
    2849     *
    2850     * @param nullText  the null text, null means no append
    2851     * @return this, to enable chaining
    2852     */
    2853    public StrBuilder setNullText(String nullText) {
    2854        if (nullText != null && nullText.isEmpty()) {
    2855            nullText = null;
    2856        }
    2857        this.nullText = nullText;
    2858        return this;
    2859    }
    2860
    2861    /**
    2862     * Gets the length of the string builder.
    2863     * <p>
    2864     * This method is the same as {@link #length()} and is provided to match the
    2865     * API of Collections.
    2866     * </p>
    2867     *
    2868     * @return The length
    2869     */
    2870    public int size() {
    2871        return size;
    2872    }
    2873
    2874    /**
    2875     * Checks whether this builder starts with the specified string.
    2876     * <p>
    2877     * Note that this method handles null input quietly, unlike String.
    2878     * </p>
    2879     *
    2880     * @param str  the string to search for, null returns false
    2881     * @return true if the builder starts with the string
    2882     */
    2883    public boolean startsWith(final String str) {
    2884        if (str == null) {
    2885            return false;
    2886        }
    2887        final int len = str.length();
    2888        if (len == 0) {
    2889            return true;
    2890        }
    2891        if (len > size) {
    2892            return false;
    2893        }
    2894        for (int i = 0; i < len; i++) {
    2895            if (buffer[i] != str.charAt(i)) {
    2896                return false;
    2897            }
    2898        }
    2899        return true;
    2900    }
    2901
    2902    /**
    2903     * {@inheritDoc}
    2904     */
    2905    @Override
    2906    public CharSequence subSequence(final int startIndex, final int endIndex) {
    2907      if (startIndex < 0) {
    2908          throw new StringIndexOutOfBoundsException(startIndex);
    2909      }
    2910      if (endIndex > size) {
    2911          throw new StringIndexOutOfBoundsException(endIndex);
    2912      }
    2913      if (startIndex > endIndex) {
    2914          throw new StringIndexOutOfBoundsException(endIndex - startIndex);
    2915      }
    2916      return substring(startIndex, endIndex);
    2917    }
    2918
    2919    /**
    2920     * Extracts a portion of this string builder as a string.
    2921     *
    2922     * @param start  the start index, inclusive, must be valid
    2923     * @return The new string
    2924     * @throws IndexOutOfBoundsException if the index is invalid
    2925     */
    2926    public String substring(final int start) {
    2927        return substring(start, size);
    2928    }
    2929
    2930    /**
    2931     * Extracts a portion of this string builder as a string.
    2932     * <p>
    2933     * Note: This method treats an endIndex greater than the length of the
    2934     * builder as equal to the length of the builder, and continues
    2935     * without error, unlike StringBuffer or String.
    2936     *
    2937     * @param startIndex  the start index, inclusive, must be valid
    2938     * @param endIndex  the end index, exclusive, must be valid except
    2939     *  that if too large it is treated as end of string
    2940     * @return The new string
    2941     * @throws IndexOutOfBoundsException if the index is invalid
    2942     */
    2943    public String substring(final int startIndex, int endIndex) {
    2944        endIndex = validateRange(startIndex, endIndex);
    2945        return new String(buffer, startIndex, endIndex - startIndex);
    2946    }
    2947
    2948    /**
    2949     * Copies the builder's character array into a new character array.
    2950     *
    2951     * @return a new array that represents the contents of the builder
    2952     */
    2953    public char[] toCharArray() {
    2954        return size == 0 ? ArrayUtils.EMPTY_CHAR_ARRAY : Arrays.copyOf(buffer, size);
    2955    }
    2956
    2957    /**
    2958     * Copies part of the builder's character array into a new character array.
    2959     *
    2960     * @param startIndex  the start index, inclusive, must be valid
    2961     * @param endIndex  the end index, exclusive, must be valid except that
    2962     *  if too large it is treated as end of string
    2963     * @return a new array that holds part of the contents of the builder
    2964     * @throws IndexOutOfBoundsException if startIndex is invalid,
    2965     *  or if endIndex is invalid (but endIndex greater than size is valid)
    2966     */
    2967    public char[] toCharArray(final int startIndex, int endIndex) {
    2968        endIndex = validateRange(startIndex, endIndex);
    2969        final int len = endIndex - startIndex;
    2970        if (len == 0) {
    2971            return ArrayUtils.EMPTY_CHAR_ARRAY;
    2972        }
    2973        final char[] chars = new char[len];
    2974        System.arraycopy(buffer, startIndex, chars, 0, len);
    2975        return chars;
    2976    }
    2977
    2978    /**
    2979     * Gets a String version of the string builder, creating a new instance
    2980     * each time the method is called.
    2981     * <p>
    2982     * Note that unlike StringBuffer, the string version returned is
    2983     * independent of the string builder.
    2984     * </p>
    2985     *
    2986     * @return The builder as a String
    2987     */
    2988    @Override
    2989    public String toString() {
    2990        return new String(buffer, 0, size);
    2991    }
    2992
    2993    /**
    2994     * Gets a StringBuffer version of the string builder, creating a
    2995     * new instance each time the method is called.
    2996     *
    2997     * @return The builder as a StringBuffer
    2998     */
    2999    public StringBuffer toStringBuffer() {
    3000        return new StringBuffer(size).append(buffer, 0, size);
    3001    }
    3002
    3003    /**
    3004     * Gets a StringBuilder version of the string builder, creating a
    3005     * new instance each time the method is called.
    3006     *
    3007     * @return The builder as a StringBuilder
    3008     */
    3009    public StringBuilder toStringBuilder() {
    3010        return new StringBuilder(size).append(buffer, 0, size);
    3011    }
    3012
    3013    /**
    3014     * Trims the builder by removing characters less than or equal to a space
    3015     * from the beginning and end.
    3016     *
    3017     * @return this, to enable chaining
    3018     */
    3019    public StrBuilder trim() {
    3020        if (size == 0) {
    3021            return this;
    3022        }
    3023        int len = size;
    3024        final char[] buf = buffer;
    3025        int pos = 0;
    3026        while (pos < len && buf[pos] <= ' ') {
    3027            pos++;
    3028        }
    3029        while (pos < len && buf[len - 1] <= ' ') {
    3030            len--;
    3031        }
    3032        if (len < size) {
    3033            delete(len, size);
    3034        }
    3035        if (pos > 0) {
    3036            delete(0, pos);
    3037        }
    3038        return this;
    3039    }
    3040
    3041    /**
    3042     * Validates parameters defining a single index in the builder.
    3043     *
    3044     * @param index  the index, must be valid
    3045     * @throws IndexOutOfBoundsException if the index is invalid
    3046     */
    3047    protected void validateIndex(final int index) {
    3048        if (index < 0 || index > size) {
    3049            throw new StringIndexOutOfBoundsException(index);
    3050        }
    3051    }
    3052
    3053    /**
    3054     * Validates parameters defining a range of the builder.
    3055     *
    3056     * @param startIndex  the start index, inclusive, must be valid
    3057     * @param endIndex  the end index, exclusive, must be valid except
    3058     *  that if too large it is treated as end of string
    3059     * @return The new string
    3060     * @throws IndexOutOfBoundsException if the index is invalid
    3061     */
    3062    protected int validateRange(final int startIndex, int endIndex) {
    3063        if (startIndex < 0) {
    3064            throw new StringIndexOutOfBoundsException(startIndex);
    3065        }
    3066        if (endIndex > size) {
    3067            endIndex = size;
    3068        }
    3069        if (startIndex > endIndex) {
    3070            throw new StringIndexOutOfBoundsException("end < start");
    3071        }
    3072        return endIndex;
    3073    }
    3074
    3075}