85 lines
2.7 KiB
Java
85 lines
2.7 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.io.filefilter;
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import java.io.File;
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import java.io.Serializable;
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/**
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* This filter accepts files or directories that are empty.
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* <p>
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* If the <code>File</code> is a directory it checks that
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* it contains no files.
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* <p>
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* Example, showing how to print out a list of the
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* current directory's empty files/directories:
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*
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* <pre>
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* File dir = new File(".");
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* String[] files = dir.list( EmptyFileFilter.EMPTY );
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* for ( int i = 0; i < files.length; i++ ) {
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* System.out.println(files[i]);
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* }
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* </pre>
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*
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* <p>
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* Example, showing how to print out a list of the
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* current directory's non-empty files/directories:
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*
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* <pre>
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* File dir = new File(".");
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* String[] files = dir.list( EmptyFileFilter.NOT_EMPTY );
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* for ( int i = 0; i < files.length; i++ ) {
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* System.out.println(files[i]);
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* }
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* </pre>
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*
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* @since Commons IO 1.3
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* @version $Revision: 587916 $
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*/
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public class EmptyFileFilter extends AbstractFileFilter implements Serializable {
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/** Singleton instance of <i>empty</i> filter */
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public static final IOFileFilter EMPTY = new EmptyFileFilter();
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/** Singleton instance of <i>not-empty</i> filter */
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public static final IOFileFilter NOT_EMPTY = new NotFileFilter(EMPTY);
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/**
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* Restrictive consructor.
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*/
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protected EmptyFileFilter() {
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}
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/**
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* Checks to see if the file is empty.
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*
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* @param file the file or directory to check
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* @return <code>true</code> if the file or directory
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* is <i>empty</i>, otherwise <code>false</code>.
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*/
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public boolean accept(File file) {
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if (file.isDirectory()) {
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File[] files = file.listFiles();
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return (files == null || files.length == 0);
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} else {
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return (file.length() == 0);
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}
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}
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}
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