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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.io.comparator;

import java.io.File;
import java.io.Serializable;
import java.util.Comparator;

import org.apache.commons.io.IOCase;

/**
 * Compare the names of two files for order (see {@link File#getName()}).
 * 

* This comparator can be used to sort lists or arrays of files * by their name either in a case-sensitive, case-insensitive or * system dependent case sensitive way. A number of singleton instances * are provided for the various case sensitivity options (using {@link IOCase}) * and the reverse of those options. *

* Example of a case-sensitive file name sort using the * {@link #NAME_COMPARATOR} singleton instance: *

 *       List<File> list = ...
 *       ((AbstractFileComparator) NameFileComparator.NAME_COMPARATOR).sort(list);
 * 
*

* Example of a reverse case-insensitive file name sort using the * {@link #NAME_INSENSITIVE_REVERSE} singleton instance: *

 *       File[] array = ...
 *       ((AbstractFileComparator) NameFileComparator.NAME_INSENSITIVE_REVERSE).sort(array);
 * 
*

* * @since 1.4 */ public class NameFileComparator extends AbstractFileComparator implements Serializable { private static final long serialVersionUID = 8397947749814525798L; /** Case-sensitive name comparator instance (see {@link IOCase#SENSITIVE}) */ public static final Comparator NAME_COMPARATOR = new NameFileComparator(); /** Reverse case-sensitive name comparator instance (see {@link IOCase#SENSITIVE}) */ public static final Comparator NAME_REVERSE = new ReverseComparator(NAME_COMPARATOR); /** Case-insensitive name comparator instance (see {@link IOCase#INSENSITIVE}) */ public static final Comparator NAME_INSENSITIVE_COMPARATOR = new NameFileComparator(IOCase.INSENSITIVE); /** Reverse case-insensitive name comparator instance (see {@link IOCase#INSENSITIVE}) */ public static final Comparator NAME_INSENSITIVE_REVERSE = new ReverseComparator(NAME_INSENSITIVE_COMPARATOR); /** System sensitive name comparator instance (see {@link IOCase#SYSTEM}) */ public static final Comparator NAME_SYSTEM_COMPARATOR = new NameFileComparator(IOCase.SYSTEM); /** Reverse system sensitive name comparator instance (see {@link IOCase#SYSTEM}) */ public static final Comparator NAME_SYSTEM_REVERSE = new ReverseComparator(NAME_SYSTEM_COMPARATOR); /** Whether the comparison is case sensitive. */ private final IOCase caseSensitivity; /** * Construct a case sensitive file name comparator instance. */ public NameFileComparator() { this.caseSensitivity = IOCase.SENSITIVE; } /** * Construct a file name comparator instance with the specified case-sensitivity. * * @param caseSensitivity how to handle case sensitivity, null means case-sensitive */ public NameFileComparator(final IOCase caseSensitivity) { this.caseSensitivity = caseSensitivity == null ? IOCase.SENSITIVE : caseSensitivity; } /** * Compare the names of two files with the specified case sensitivity. * * @param file1 The first file to compare * @param file2 The second file to compare * @return a negative value if the first file's name * is less than the second, zero if the names are the * same and a positive value if the first files name * is greater than the second file. */ @Override public int compare(final File file1, final File file2) { return caseSensitivity.checkCompareTo(file1.getName(), file2.getName()); } /** * String representation of this file comparator. * * @return String representation of this file comparator */ @Override public String toString() { return super.toString() + "[caseSensitivity=" + caseSensitivity + "]"; } }





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