| /* |
| * 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.vfs2.filter; |
| |
| import java.io.Serializable; |
| |
| import org.apache.commons.vfs2.FileContent; |
| import org.apache.commons.vfs2.FileFilter; |
| import org.apache.commons.vfs2.FileObject; |
| import org.apache.commons.vfs2.FileSelectInfo; |
| import org.apache.commons.vfs2.FileSystemException; |
| import org.apache.commons.vfs2.FileType; |
| |
| /** |
| * This filter accepts files or directories that are empty. |
| * <p> |
| * If the {@code File} is a directory it checks that it contains no files. |
| * </p> |
| * <p> |
| * Example, showing how to print out a list of the current directory's empty files/directories: |
| * </p> |
| * |
| * <pre> |
| * FileSystemManager fsManager = VFS.getManager(); |
| * FileObject dir = fsManager.toFileObject(new File(".")); |
| * FileObject[] files = dir.findFiles(new FileFilterSelector(EmptyFileFilter.EMPTY)); |
| * for (int i = 0; i < files.length; i++) { |
| * System.out.println(files[i]); |
| * } |
| * </pre> |
| * |
| * <p> |
| * Example, showing how to print out a list of the current directory's non-empty files/directories: |
| * </p> |
| * |
| * <pre> |
| * FileSystemManager fsManager = VFS.getManager(); |
| * FileObject dir = fsManager.toFileObject(new File(".")); |
| * FileObject[] files = dir.findFiles(new FileFilterSelector(EmptyFileFilter.NOT_EMPTY)); |
| * for (int i = 0; i < files.length; i++) { |
| * System.out.println(files[i]); |
| * } |
| * </pre> |
| * |
| * @author This code was originally ported from Apache Commons IO File Filter |
| * @see "http://commons.apache.org/proper/commons-io/" |
| * @since 2.4 |
| */ |
| public class EmptyFileFilter implements FileFilter, Serializable { |
| |
| private static final long serialVersionUID = 1L; |
| |
| /** Singleton instance of <i>empty</i> filter. */ |
| public static final FileFilter EMPTY = new EmptyFileFilter(); |
| |
| /** Singleton instance of <i>not-empty</i> filter. */ |
| public static final FileFilter NOT_EMPTY = new NotFileFilter(EMPTY); |
| |
| /** |
| * Restrictive constructor. |
| */ |
| protected EmptyFileFilter() { |
| } |
| |
| /** |
| * Checks to see if the file is empty. A non-existing file is also considered empty. |
| * |
| * @param fileSelectInfo the file or directory to check |
| * |
| * @return {@code true} if the file or directory is <i>empty</i>, otherwise {@code false}. |
| * @throws FileSystemException Thrown for file system errors. |
| */ |
| @Override |
| public boolean accept(final FileSelectInfo fileSelectInfo) throws FileSystemException { |
| try (final FileObject file = fileSelectInfo.getFile()) { |
| if (!file.exists()) { |
| return true; |
| } |
| if (file.getType() == FileType.FOLDER) { |
| final FileObject[] files = file.getChildren(); |
| return files == null || files.length == 0; |
| } |
| try (final FileContent content = file.getContent()) { |
| return content.isEmpty(); |
| } |
| } |
| } |
| |
| } |