| /* |
| * 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.FilenameUtils; |
| import org.apache.commons.io.IOCase; |
| |
| /** |
| * Compare the file name <b>extensions</b> for order |
| * (see {@link FilenameUtils#getExtension(String)}). |
| * <p> |
| * This comparator can be used to sort lists or arrays of files |
| * by their file extension 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. |
| * </p> |
| * <p> |
| * Example of a <i>case-sensitive</i> file extension sort using the |
| * {@link #EXTENSION_COMPARATOR} singleton instance: |
| * </p> |
| * <pre> |
| * List<File> list = ... |
| * ((AbstractFileComparator) ExtensionFileComparator.EXTENSION_COMPARATOR).sort(list); |
| * </pre> |
| * <p> |
| * Example of a <i>reverse case-insensitive</i> file extension sort using the |
| * {@link #EXTENSION_INSENSITIVE_REVERSE} singleton instance: |
| * </p> |
| * <pre> |
| * File[] array = ... |
| * ((AbstractFileComparator) ExtensionFileComparator.EXTENSION_INSENSITIVE_REVERSE).sort(array); |
| * </pre> |
| * <h2>Deprecating Serialization</h2> |
| * <p> |
| * <em>Serialization is deprecated and will be removed in 3.0.</em> |
| * </p> |
| * |
| * @since 1.4 |
| */ |
| public class ExtensionFileComparator extends AbstractFileComparator implements Serializable { |
| |
| private static final long serialVersionUID = 1928235200184222815L; |
| |
| /** Case-sensitive extension comparator instance (see {@link IOCase#SENSITIVE}) */ |
| public static final Comparator<File> EXTENSION_COMPARATOR = new ExtensionFileComparator(); |
| |
| /** Reverse case-sensitive extension comparator instance (see {@link IOCase#SENSITIVE}) */ |
| public static final Comparator<File> EXTENSION_REVERSE = new ReverseFileComparator(EXTENSION_COMPARATOR); |
| |
| /** Case-insensitive extension comparator instance (see {@link IOCase#INSENSITIVE}) */ |
| public static final Comparator<File> EXTENSION_INSENSITIVE_COMPARATOR |
| = new ExtensionFileComparator(IOCase.INSENSITIVE); |
| |
| /** Reverse case-insensitive extension comparator instance (see {@link IOCase#INSENSITIVE}) */ |
| public static final Comparator<File> EXTENSION_INSENSITIVE_REVERSE |
| = new ReverseFileComparator(EXTENSION_INSENSITIVE_COMPARATOR); |
| |
| /** System sensitive extension comparator instance (see {@link IOCase#SYSTEM}) */ |
| public static final Comparator<File> EXTENSION_SYSTEM_COMPARATOR = new ExtensionFileComparator(IOCase.SYSTEM); |
| |
| /** Reverse system sensitive path comparator instance (see {@link IOCase#SYSTEM}) */ |
| public static final Comparator<File> EXTENSION_SYSTEM_REVERSE = new ReverseFileComparator(EXTENSION_SYSTEM_COMPARATOR); |
| |
| /** Whether the comparison is case-sensitive. */ |
| private final IOCase ioCase; |
| |
| /** |
| * Constructs a case-sensitive file extension comparator instance. |
| */ |
| public ExtensionFileComparator() { |
| this.ioCase = IOCase.SENSITIVE; |
| } |
| |
| /** |
| * Constructs a file extension comparator instance with the specified case-sensitivity. |
| * |
| * @param ioCase how to handle case sensitivity, null means case-sensitive |
| */ |
| public ExtensionFileComparator(final IOCase ioCase) { |
| this.ioCase = IOCase.value(ioCase, IOCase.SENSITIVE); |
| } |
| |
| /** |
| * Compares the extensions of two files 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 extension |
| * is less than the second, zero if the extensions are the |
| * same and a positive value if the first files extension |
| * is greater than the second file. |
| */ |
| @Override |
| public int compare(final File file1, final File file2) { |
| final String suffix1 = FilenameUtils.getExtension(file1.getName()); |
| final String suffix2 = FilenameUtils.getExtension(file2.getName()); |
| return ioCase.checkCompareTo(suffix1, suffix2); |
| } |
| |
| /** |
| * String representation of this file comparator. |
| * |
| * @return String representation of this file comparator |
| */ |
| @Override |
| public String toString() { |
| return super.toString() + "[ioCase=" + ioCase + "]"; |
| } |
| } |