    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.io;
    018
    019import java.util.Objects;
    020
    021/**
    022 * Enumeration of IO case sensitivity.
    023 * <p>
    024 * Different filing systems have different rules for case-sensitivity.
    025 * Windows is case-insensitive, Unix is case-sensitive.
    026 * <p>
    027 * This class captures that difference, providing an enumeration to
    028 * control how file name comparisons should be performed. It also provides
    029 * methods that use the enumeration to perform comparisons.
    030 * <p>
    031 * Wherever possible, you should use the <code>check</code> methods in this
    032 * class to compare file names.
    033 *
    034 * @since 1.3
    035 */
    036public enum IOCase {
    037
    038    /**
    039     * The constant for case sensitive regardless of operating system.
    040     */
    041    SENSITIVE ("Sensitive", true),
    042
    043    /**
    044     * The constant for case insensitive regardless of operating system.
    045     */
    046    INSENSITIVE ("Insensitive", false),
    047
    048    /**
    049     * The constant for case sensitivity determined by the current operating system.
    050     * Windows is case-insensitive when comparing file names, Unix is case-sensitive.
    051     * <p>
    052     * <strong>Note:</strong> This only caters for Windows and Unix. Other operating
    053     * systems (e.g. OSX and OpenVMS) are treated as case sensitive if they use the
    054     * Unix file separator and case-insensitive if they use the Windows file separator
    055     * (see {@link java.io.File#separatorChar}).
    056     * <p>
    057     * If you serialize this constant on Windows, and deserialize on Unix, or vice
    058     * versa, then the value of the case-sensitivity flag will change.
    059     */
    060    SYSTEM ("System", !FilenameUtils.isSystemWindows());
    061
    062    /** Serialization version. */
    063    private static final long serialVersionUID = -6343169151696340687L;
    064
    065    /** The enumeration name. */
    066    private final String name;
    067
    068    /** The sensitivity flag. */
    069    private final transient boolean sensitive;
    070
    071    //-----------------------------------------------------------------------
    072    /**
    073     * Factory method to create an IOCase from a name.
    074     *
    075     * @param name  the name to find
    076     * @return the IOCase object
    077     * @throws IllegalArgumentException if the name is invalid
    078     */
    079    public static IOCase forName(final String name) {
    080        for (final IOCase ioCase : IOCase.values())
    081        {
    082            if (ioCase.getName().equals(name))
    083            {
    084                return ioCase;
    085            }
    086        }
    087        throw new IllegalArgumentException("Invalid IOCase name: " + name);
    088    }
    089
    090    //-----------------------------------------------------------------------
    091    /**
    092     * Constructs a new instance.
    093     *
    094     * @param name  the name
    095     * @param sensitive  the sensitivity
    096     */
    097    IOCase(final String name, final boolean sensitive) {
    098        this.name = name;
    099        this.sensitive = sensitive;
    100    }
    101
    102    /**
    103     * Replaces the enumeration from the stream with a real one.
    104     * This ensures that the correct flag is set for SYSTEM.
    105     *
    106     * @return the resolved object
    107     */
    108    private Object readResolve() {
    109        return forName(name);
    110    }
    111
    112    //-----------------------------------------------------------------------
    113    /**
    114     * Gets the name of the constant.
    115     *
    116     * @return the name of the constant
    117     */
    118    public String getName() {
    119        return name;
    120    }
    121
    122    /**
    123     * Does the object represent case sensitive comparison.
    124     *
    125     * @return true if case sensitive
    126     */
    127    public boolean isCaseSensitive() {
    128        return sensitive;
    129    }
    130
    131    //-----------------------------------------------------------------------
    132    /**
    133     * Compares two strings using the case-sensitivity rule.
    134     * <p>
    135     * This method mimics {@link String#compareTo} but takes case-sensitivity
    136     * into account.
    137     *
    138     * @param str1  the first string to compare, not null
    139     * @param str2  the second string to compare, not null
    140     * @return true if equal using the case rules
    141     * @throws NullPointerException if either string is null
    142     */
    143    public int checkCompareTo(final String str1, final String str2) {
    144        Objects.requireNonNull(str1, "str1");
    145        Objects.requireNonNull(str2, "str2");
    146        return sensitive ? str1.compareTo(str2) : str1.compareToIgnoreCase(str2);
    147    }
    148
    149    /**
    150     * Compares two strings using the case-sensitivity rule.
    151     * <p>
    152     * This method mimics {@link String#equals} but takes case-sensitivity
    153     * into account.
    154     *
    155     * @param str1  the first string to compare, not null
    156     * @param str2  the second string to compare, not null
    157     * @return true if equal using the case rules
    158     * @throws NullPointerException if either string is null
    159     */
    160    public boolean checkEquals(final String str1, final String str2) {
    161        Objects.requireNonNull(str1, "str1");
    162        Objects.requireNonNull(str2, "str2");
    163        return sensitive ? str1.equals(str2) : str1.equalsIgnoreCase(str2);
    164    }
    165
    166    /**
    167     * Checks if one string starts with another using the case-sensitivity rule.
    168     * <p>
    169     * This method mimics {@link String#startsWith(String)} but takes case-sensitivity
    170     * into account.
    171     *
    172     * @param str  the string to check, not null
    173     * @param start  the start to compare against, not null
    174     * @return true if equal using the case rules
    175     * @throws NullPointerException if either string is null
    176     */
    177    public boolean checkStartsWith(final String str, final String start) {
    178        return str.regionMatches(!sensitive, 0, start, 0, start.length());
    179    }
    180
    181    /**
    182     * Checks if one string ends with another using the case-sensitivity rule.
    183     * <p>
    184     * This method mimics {@link String#endsWith} but takes case-sensitivity
    185     * into account.
    186     *
    187     * @param str  the string to check, not null
    188     * @param end  the end to compare against, not null
    189     * @return true if equal using the case rules
    190     * @throws NullPointerException if either string is null
    191     */
    192    public boolean checkEndsWith(final String str, final String end) {
    193        final int endLen = end.length();
    194        return str.regionMatches(!sensitive, str.length() - endLen, end, 0, endLen);
    195    }
    196
    197    /**
    198     * Checks if one string contains another starting at a specific index using the
    199     * case-sensitivity rule.
    200     * <p>
    201     * This method mimics parts of {@link String#indexOf(String, int)}
    202     * but takes case-sensitivity into account.
    203     *
    204     * @param str  the string to check, not null
    205     * @param strStartIndex  the index to start at in str
    206     * @param search  the start to search for, not null
    207     * @return the first index of the search String,
    208     *  -1 if no match or {@code null} string input
    209     * @throws NullPointerException if either string is null
    210     * @since 2.0
    211     */
    212    public int checkIndexOf(final String str, final int strStartIndex, final String search) {
    213        final int endIndex = str.length() - search.length();
    214        if (endIndex >= strStartIndex) {
    215            for (int i = strStartIndex; i <= endIndex; i++) {
    216                if (checkRegionMatches(str, i, search)) {
    217                    return i;
    218                }
    219            }
    220        }
    221        return -1;
    222    }
    223
    224    /**
    225     * Checks if one string contains another at a specific index using the case-sensitivity rule.
    226     * <p>
    227     * This method mimics parts of {@link String#regionMatches(boolean, int, String, int, int)}
    228     * but takes case-sensitivity into account.
    229     *
    230     * @param str  the string to check, not null
    231     * @param strStartIndex  the index to start at in str
    232     * @param search  the start to search for, not null
    233     * @return true if equal using the case rules
    234     * @throws NullPointerException if either string is null
    235     */
    236    public boolean checkRegionMatches(final String str, final int strStartIndex, final String search) {
    237        return str.regionMatches(!sensitive, strStartIndex, search, 0, search.length());
    238    }
    239
    240    //-----------------------------------------------------------------------
    241    /**
    242     * Gets a string describing the sensitivity.
    243     *
    244     * @return a string describing the sensitivity
    245     */
    246    @Override
    247    public String toString() {
    248        return name;
    249    }
    250
    251}