157 lines
5.8 KiB
Java
157 lines
5.8 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;
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import java.io.File;
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import java.io.IOException;
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/**
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* Strategy for deleting files.
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* <p>
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* There is more than one way to delete a file.
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* You may want to limit access to certain directories, to only delete
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* directories if they are empty, or maybe to force deletion.
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* <p>
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* This class captures the strategy to use and is designed for user subclassing.
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*
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* @author Stephen Colebourne
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* @version $Id: FileDeleteStrategy.java 453903 2006-10-07 13:47:06Z scolebourne $
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* @since Commons IO 1.3
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*/
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public class FileDeleteStrategy {
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/**
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* The singleton instance for normal file deletion, which does not permit
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* the deletion of directories that are not empty.
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*/
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public static final FileDeleteStrategy NORMAL = new FileDeleteStrategy("Normal");
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/**
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* The singleton instance for forced file deletion, which always deletes,
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* even if the file represents a non-empty directory.
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*/
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public static final FileDeleteStrategy FORCE = new ForceFileDeleteStrategy();
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/** The name of the strategy. */
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private final String name;
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//-----------------------------------------------------------------------
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/**
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* Restricted constructor.
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*
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* @param name the name by which the strategy is known
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*/
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protected FileDeleteStrategy(String name) {
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this.name = name;
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}
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//-----------------------------------------------------------------------
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/**
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* Deletes the file object, which may be a file or a directory.
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* All <code>IOException</code>s are caught and false returned instead.
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* If the file does not exist or is null, true is returned.
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* <p>
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* Subclass writers should override {@link #doDelete(File)}, not this method.
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*
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* @param fileToDelete the file to delete, null returns true
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* @return true if the file was deleted, or there was no such file
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*/
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public boolean deleteQuietly(File fileToDelete) {
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if (fileToDelete == null || fileToDelete.exists() == false) {
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return true;
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}
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try {
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return doDelete(fileToDelete);
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} catch (IOException ex) {
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return false;
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}
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}
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/**
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* Deletes the file object, which may be a file or a directory.
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* If the file does not exist, the method just returns.
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* <p>
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* Subclass writers should override {@link #doDelete(File)}, not this method.
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*
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* @param fileToDelete the file to delete, not null
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* @throws NullPointerException if the file is null
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* @throws IOException if an error occurs during file deletion
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*/
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public void delete(File fileToDelete) throws IOException {
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if (fileToDelete.exists() && doDelete(fileToDelete) == false) {
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throw new IOException("Deletion failed: " + fileToDelete);
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}
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}
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/**
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* Actually deletes the file object, which may be a file or a directory.
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* <p>
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* This method is designed for subclasses to override.
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* The implementation may return either false or an <code>IOException</code>
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* when deletion fails. The {@link #delete(File)} and {@link #deleteQuietly(File)}
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* methods will handle either response appropriately.
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* A check has been made to ensure that the file will exist.
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* <p>
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* This implementation uses {@link File#delete()}.
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*
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* @param fileToDelete the file to delete, exists, not null
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* @return true if the file was deleteds
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* @throws NullPointerException if the file is null
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* @throws IOException if an error occurs during file deletion
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*/
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protected boolean doDelete(File fileToDelete) throws IOException {
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return fileToDelete.delete();
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}
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//-----------------------------------------------------------------------
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/**
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* Gets a string describing the delete strategy.
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*
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* @return a string describing the delete strategy
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*/
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public String toString() {
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return "FileDeleteStrategy[" + name + "]";
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}
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//-----------------------------------------------------------------------
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/**
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* Force file deletion strategy.
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*/
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static class ForceFileDeleteStrategy extends FileDeleteStrategy {
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/** Default Constructor */
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ForceFileDeleteStrategy() {
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super("Force");
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}
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/**
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* Deletes the file object.
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* <p>
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* This implementation uses <code>FileUtils.forceDelete() <code>
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* if the file exists.
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*
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* @param fileToDelete the file to delete, not null
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* @return Always returns <code>true</code>
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* @throws NullPointerException if the file is null
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* @throws IOException if an error occurs during file deletion
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*/
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protected boolean doDelete(File fileToDelete) throws IOException {
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FileUtils.forceDelete(fileToDelete);
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return true;
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}
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}
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}
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