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 *
017 */
018
019package org.apache.commons.compress.utils;
020
021import java.io.File;
022import java.nio.file.Path;
023
024/**
025 * Generic file name utilities.
026 * @since 1.20
027 */
028public class FileNameUtils {
029
030    private static String fileNameToBaseName(final String name) {
031        final int extensionIndex = name.lastIndexOf('.');
032        return extensionIndex < 0 ? name : name.substring(0, extensionIndex);
033    }
034
035    private static String fileNameToExtension(final String name) {
036        final int extensionIndex = name.lastIndexOf('.');
037        return extensionIndex < 0 ? "" : name.substring(extensionIndex + 1);
038    }
039
040    /**
041     * Gets the basename (i.e. the part up to and not including the
042     * last ".") of the last path segment of a filename.
043     * <p>Will return the file name itself if it doesn't contain any
044     * dots. All leading directories of the {@code filename} parameter
045     * are skipped.</p>
046     * @return the basename of filename
047     * @param path the path of the file to obtain the basename of.
048     * @since 1.22
049     */
050    public static String getBaseName(final Path path) {
051        if (path == null) {
052            return null;
053        }
054        return fileNameToBaseName(path.getFileName().toString());
055    }
056
057    /**
058     * Gets the basename (i.e. the part up to and not including the
059     * last ".") of the last path segment of a filename.
060     *
061     * <p>Will return the file name itself if it doesn't contain any
062     * dots. All leading directories of the {@code filename} parameter
063     * are skipped.</p>
064     *
065     * @return the basename of filename
066     * @param filename the name of the file to obtain the basename of.
067     */
068    public static String getBaseName(final String filename) {
069        if (filename == null) {
070            return null;
071        }
072        return fileNameToBaseName(new File(filename).getName());
073    }
074
075    /**
076     * Gets the extension (i.e. the part after the last ".") of a file.
077     * <p>Will return an empty string if the file name doesn't contain
078     * any dots. Only the last segment of a the file name is consulted
079     * - i.e. all leading directories of the {@code filename}
080     * parameter are skipped.</p>
081     * @return the extension of filename
082     * @param path the path of the file to obtain the extension of.
083     * @since 1.22
084     */
085    public static String getExtension(final Path path) {
086        if (path == null) {
087            return null;
088        }
089        return fileNameToExtension(path.getFileName().toString());
090    }
091
092    /**
093     * Gets the extension (i.e. the part after the last ".") of a file.
094     *
095     * <p>Will return an empty string if the file name doesn't contain
096     * any dots. Only the last segment of a the file name is consulted
097     * - i.e. all leading directories of the {@code filename}
098     * parameter are skipped.</p>
099     *
100     * @return the extension of filename
101     * @param filename the name of the file to obtain the extension of.
102     */
103    public static String getExtension(final String filename) {
104        if (filename == null) {
105            return null;
106        }
107        return fileNameToExtension(new File(filename).getName());
108    }
109}