    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        final Path fileName = path.getFileName();
    055        return fileName != null ? fileNameToBaseName(fileName.toString()) : null;
    056    }
    057
    058    /**
    059     * Gets the basename (i.e. the part up to and not including the
    060     * last ".") of the last path segment of a filename.
    061     *
    062     * <p>Will return the file name itself if it doesn't contain any
    063     * dots. All leading directories of the {@code filename} parameter
    064     * are skipped.</p>
    065     *
    066     * @return the basename of filename
    067     * @param filename the name of the file to obtain the basename of.
    068     */
    069    public static String getBaseName(final String filename) {
    070        if (filename == null) {
    071            return null;
    072        }
    073        return fileNameToBaseName(new File(filename).getName());
    074    }
    075
    076    /**
    077     * Gets the extension (i.e. the part after the last ".") of a file.
    078     * <p>Will return an empty string if the file name doesn't contain
    079     * any dots. Only the last segment of a the file name is consulted
    080     * - i.e. all leading directories of the {@code filename}
    081     * parameter are skipped.</p>
    082     * @return the extension of filename
    083     * @param path the path of the file to obtain the extension of.
    084     * @since 1.22
    085     */
    086    public static String getExtension(final Path path) {
    087        if (path == null) {
    088            return null;
    089        }
    090        final Path fileName = path.getFileName();
    091        return fileName != null ? fileNameToExtension(fileName.toString()) : null;
    092    }
    093
    094    /**
    095     * Gets the extension (i.e. the part after the last ".") of a file.
    096     *
    097     * <p>Will return an empty string if the file name doesn't contain
    098     * any dots. Only the last segment of a the file name is consulted
    099     * - i.e. all leading directories of the {@code filename}
    100     * parameter are skipped.</p>
    101     *
    102     * @return the extension of filename
    103     * @param filename the name of the file to obtain the extension of.
    104     */
    105    public static String getExtension(final String filename) {
    106        if (filename == null) {
    107            return null;
    108        }
    109        return fileNameToExtension(new File(filename).getName());
    110    }
    111}