    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.lang3;
    018
    019/**
    020 * <p>Operations on {@code CharSet} instances.</p>
    021 *
    022 * <p>This class handles {@code null} input gracefully.
    023 * An exception will not be thrown for a {@code null} input.
    024 * Each method documents its behaviour in more detail.</p>
    025 *
    026 * <p>#ThreadSafe#</p>
    027 * @see CharSet
    028 * @since 1.0
    029 */
    030public class CharSetUtils {
    031
    032    /**
    033     * <p>Takes an argument in set-syntax, see evaluateSet,
    034     * and identifies whether any of the characters are present in the specified string.</p>
    035     *
    036     * <pre>
    037     * CharSetUtils.containsAny(null, *)        = false
    038     * CharSetUtils.containsAny("", *)          = false
    039     * CharSetUtils.containsAny(*, null)        = false
    040     * CharSetUtils.containsAny(*, "")          = false
    041     * CharSetUtils.containsAny("hello", "k-p") = true
    042     * CharSetUtils.containsAny("hello", "a-d") = false
    043     * </pre>
    044     *
    045     * @see CharSet#getInstance(java.lang.String...) for set-syntax.
    046     * @param str  String to look for characters in, may be null
    047     * @param set  String[] set of characters to identify, may be null
    048     * @return whether or not the characters in the set are in the primary string
    049     * @since 3.2
    050     */
    051    public static boolean containsAny(final String str, final String... set) {
    052        if (StringUtils.isEmpty(str) || deepEmpty(set)) {
    053            return false;
    054        }
    055        final CharSet chars = CharSet.getInstance(set);
    056        for (final char c : str.toCharArray()) {
    057            if (chars.contains(c)) {
    058                return true;
    059            }
    060        }
    061        return false;
    062    }
    063
    064    /**
    065     * <p>Takes an argument in set-syntax, see evaluateSet,
    066     * and returns the number of characters present in the specified string.</p>
    067     *
    068     * <pre>
    069     * CharSetUtils.count(null, *)        = 0
    070     * CharSetUtils.count("", *)          = 0
    071     * CharSetUtils.count(*, null)        = 0
    072     * CharSetUtils.count(*, "")          = 0
    073     * CharSetUtils.count("hello", "k-p") = 3
    074     * CharSetUtils.count("hello", "a-e") = 1
    075     * </pre>
    076     *
    077     * @see CharSet#getInstance(java.lang.String...) for set-syntax.
    078     * @param str  String to count characters in, may be null
    079     * @param set  String[] set of characters to count, may be null
    080     * @return the character count, zero if null string input
    081     */
    082    public static int count(final String str, final String... set) {
    083        if (StringUtils.isEmpty(str) || deepEmpty(set)) {
    084            return 0;
    085        }
    086        final CharSet chars = CharSet.getInstance(set);
    087        int count = 0;
    088        for (final char c : str.toCharArray()) {
    089            if (chars.contains(c)) {
    090                count++;
    091            }
    092        }
    093        return count;
    094    }
    095
    096    /**
    097     * Determines whether or not all the Strings in an array are
    098     * empty or not.
    099     *
    100     * @param strings String[] whose elements are being checked for emptiness
    101     * @return whether or not the String is empty
    102     */
    103    private static boolean deepEmpty(final String[] strings) {
    104        if (strings != null) {
    105            for (final String s : strings) {
    106                if (StringUtils.isNotEmpty(s)) {
    107                    return false;
    108                }
    109            }
    110        }
    111        return true;
    112    }
    113
    114    /**
    115     * <p>Takes an argument in set-syntax, see evaluateSet,
    116     * and deletes any of characters present in the specified string.</p>
    117     *
    118     * <pre>
    119     * CharSetUtils.delete(null, *)        = null
    120     * CharSetUtils.delete("", *)          = ""
    121     * CharSetUtils.delete(*, null)        = *
    122     * CharSetUtils.delete(*, "")          = *
    123     * CharSetUtils.delete("hello", "hl")  = "eo"
    124     * CharSetUtils.delete("hello", "le")  = "ho"
    125     * </pre>
    126     *
    127     * @see CharSet#getInstance(java.lang.String...) for set-syntax.
    128     * @param str  String to delete characters from, may be null
    129     * @param set  String[] set of characters to delete, may be null
    130     * @return the modified String, {@code null} if null string input
    131     */
    132    public static String delete(final String str, final String... set) {
    133        if (StringUtils.isEmpty(str) || deepEmpty(set)) {
    134            return str;
    135        }
    136        return modify(str, set, false);
    137    }
    138
    139    /**
    140     * <p>Takes an argument in set-syntax, see evaluateSet,
    141     * and keeps any of characters present in the specified string.</p>
    142     *
    143     * <pre>
    144     * CharSetUtils.keep(null, *)        = null
    145     * CharSetUtils.keep("", *)          = ""
    146     * CharSetUtils.keep(*, null)        = ""
    147     * CharSetUtils.keep(*, "")          = ""
    148     * CharSetUtils.keep("hello", "hl")  = "hll"
    149     * CharSetUtils.keep("hello", "le")  = "ell"
    150     * </pre>
    151     *
    152     * @see CharSet#getInstance(java.lang.String...) for set-syntax.
    153     * @param str  String to keep characters from, may be null
    154     * @param set  String[] set of characters to keep, may be null
    155     * @return the modified String, {@code null} if null string input
    156     * @since 2.0
    157     */
    158    public static String keep(final String str, final String... set) {
    159        if (str == null) {
    160            return null;
    161        }
    162        if (str.isEmpty() || deepEmpty(set)) {
    163            return StringUtils.EMPTY;
    164        }
    165        return modify(str, set, true);
    166    }
    167
    168    /**
    169     * Implementation of delete and keep
    170     *
    171     * @param str String to modify characters within
    172     * @param set String[] set of characters to modify
    173     * @param expect whether to evaluate on match, or non-match
    174     * @return the modified String, not null
    175     */
    176    private static String modify(final String str, final String[] set, final boolean expect) {
    177        final CharSet chars = CharSet.getInstance(set);
    178        final StringBuilder buffer = new StringBuilder(str.length());
    179        final char[] chrs = str.toCharArray();
    180        for (final char chr : chrs) {
    181            if (chars.contains(chr) == expect) {
    182                buffer.append(chr);
    183            }
    184        }
    185        return buffer.toString();
    186    }
    187
    188    /**
    189     * <p>Squeezes any repetitions of a character that is mentioned in the
    190     * supplied set.</p>
    191     *
    192     * <pre>
    193     * CharSetUtils.squeeze(null, *)        = null
    194     * CharSetUtils.squeeze("", *)          = ""
    195     * CharSetUtils.squeeze(*, null)        = *
    196     * CharSetUtils.squeeze(*, "")          = *
    197     * CharSetUtils.squeeze("hello", "k-p") = "helo"
    198     * CharSetUtils.squeeze("hello", "a-e") = "hello"
    199     * </pre>
    200     *
    201     * @see CharSet#getInstance(java.lang.String...) for set-syntax.
    202     * @param str  the string to squeeze, may be null
    203     * @param set  the character set to use for manipulation, may be null
    204     * @return the modified String, {@code null} if null string input
    205     */
    206    public static String squeeze(final String str, final String... set) {
    207        if (StringUtils.isEmpty(str) || deepEmpty(set)) {
    208            return str;
    209        }
    210        final CharSet chars = CharSet.getInstance(set);
    211        final StringBuilder buffer = new StringBuilder(str.length());
    212        final char[] chrs = str.toCharArray();
    213        final int sz = chrs.length;
    214        char lastChar = chrs[0];
    215        char ch = ' ';
    216        Character inChars = null;
    217        Character notInChars = null;
    218        buffer.append(lastChar);
    219        for (int i = 1; i < sz; i++) {
    220            ch = chrs[i];
    221            if (ch == lastChar) {
    222                if (inChars != null && ch == inChars) {
    223                    continue;
    224                }
    225                if (notInChars == null || ch != notInChars) {
    226                    if (chars.contains(ch)) {
    227                        inChars = ch;
    228                        continue;
    229                    }
    230                    notInChars = ch;
    231                }
    232            }
    233            buffer.append(ch);
    234            lastChar = ch;
    235        }
    236        return buffer.toString();
    237    }
    238
    239    /**
    240     * <p>CharSetUtils instances should NOT be constructed in standard programming.
    241     * Instead, the class should be used as {@code CharSetUtils.evaluateSet(null);}.</p>
    242     *
    243     * <p>This constructor is public to permit tools that require a JavaBean instance
    244     * to operate.</p>
    245     */
    246    public CharSetUtils() {
    247      super();
    248    }
    249}