/* * 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.filefilter; import java.io.File; import java.io.Serializable; /** * This filter accepts files or directories that are empty. *
* If the File
is a directory it checks that
* it contains no files.
*
* Example, showing how to print out a list of the * current directory's empty files/directories: * *
* File dir = new File("."); * String[] files = dir.list( EmptyFileFilter.EMPTY ); * for ( int i = 0; i < files.length; i++ ) { * System.out.println(files[i]); * } ** *
* Example, showing how to print out a list of the * current directory's non-empty files/directories: * *
* File dir = new File("."); * String[] files = dir.list( EmptyFileFilter.NOT_EMPTY ); * for ( int i = 0; i < files.length; i++ ) { * System.out.println(files[i]); * } ** * @since Commons IO 1.3 * @version $Revision: 587916 $ */ public class EmptyFileFilter extends AbstractFileFilter implements Serializable { /** Singleton instance of empty filter */ public static final IOFileFilter EMPTY = new EmptyFileFilter(); /** Singleton instance of not-empty filter */ public static final IOFileFilter NOT_EMPTY = new NotFileFilter(EMPTY); /** * Restrictive consructor. */ protected EmptyFileFilter() { } /** * Checks to see if the file is empty. * * @param file the file or directory to check * @return
true
if the file or directory
* is empty, otherwise false
.
*/
public boolean accept(File file) {
if (file.isDirectory()) {
File[] files = file.listFiles();
return (files == null || files.length == 0);
} else {
return (file.length() == 0);
}
}
}