/*
* 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;
import java.io.File;
import java.io.IOException;
/**
* Strategy for deleting files.
* <p>
* There is more than one way to delete a file.
* You may want to limit access to certain directories, to only delete
* directories if they are empty, or maybe to force deletion.
* <p>
* This class captures the strategy to use and is designed for user subclassing.
*
* @author Stephen Colebourne
* @version $Id: FileDeleteStrategy.java 723942 2008-12-06 01:24:06Z sebb $
* @since Commons IO 1.3
*/
public class FileDeleteStrategy {
/**
* The singleton instance for normal file deletion, which does not permit
* the deletion of directories that are not empty.
*/
public static final FileDeleteStrategy NORMAL = new FileDeleteStrategy("Normal");
/**
* The singleton instance for forced file deletion, which always deletes,
* even if the file represents a non-empty directory.
*/
public static final FileDeleteStrategy FORCE = new ForceFileDeleteStrategy();
/** The name of the strategy. */
private final String name;
//-----------------------------------------------------------------------
/**
* Restricted constructor.
*
* @param name the name by which the strategy is known
*/
protected FileDeleteStrategy(String name) {
this.name = name;
}
//-----------------------------------------------------------------------
/**
* Deletes the file object, which may be a file or a directory.
* All <code>IOException</code>s are caught and false returned instead.
* If the file does not exist or is null, true is returned.
* <p>
* Subclass writers should override {@link #doDelete(File)}, not this method.
*
* @param fileToDelete the file to delete, null returns true
* @return true if the file was deleted, or there was no such file
*/
public boolean deleteQuietly(File fileToDelete) {
if (fileToDelete == null || fileToDelete.exists() == false) {
return true;
}
try {
return doDelete(fileToDelete);
} catch (IOException ex) {
return false;
}
}
/**
* Deletes the file object, which may be a file or a directory.
* If the file does not exist, the method just returns.
* <p>
* Subclass writers should override {@link #doDelete(File)}, not this method.
*
* @param fileToDelete the file to delete, not null
* @throws NullPointerException if the file is null
* @throws IOException if an error occurs during file deletion
*/
public void delete(File fileToDelete) throws IOException {
if (fileToDelete.exists() && doDelete(fileToDelete) == false) {
throw new IOException("Deletion failed: " + fileToDelete);
}
}
/**
* Actually deletes the file object, which may be a file or a directory.
* <p>
* This method is designed for subclasses to override.
* The implementation may return either false or an <code>IOException</code>
* when deletion fails. The {@link #delete(File)} and {@link #deleteQuietly(File)}
* methods will handle either response appropriately.
* A check has been made to ensure that the file will exist.
* <p>
* This implementation uses {@link File#delete()}.
*
* @param fileToDelete the file to delete, exists, not null
* @return true if the file was deleteds
* @throws NullPointerException if the file is null
* @throws IOException if an error occurs during file deletion
*/
protected boolean doDelete(File fileToDelete) throws IOException {
return fileToDelete.delete();
}
//-----------------------------------------------------------------------
/**
* Gets a string describing the delete strategy.
*
* @return a string describing the delete strategy
*/
@Override
public String toString() {
return "FileDeleteStrategy[" + name + "]";
}
//-----------------------------------------------------------------------
/**
* Force file deletion strategy.
*/
static class ForceFileDeleteStrategy extends FileDeleteStrategy {
/** Default Constructor */
ForceFileDeleteStrategy() {
super("Force");
}
/**
* Deletes the file object.
* <p>
* This implementation uses <code>FileUtils.forceDelete() <code>
* if the file exists.
*
* @param fileToDelete the file to delete, not null
* @return Always returns <code>true</code>
* @throws NullPointerException if the file is null
* @throws IOException if an error occurs during file deletion
*/
@Override
protected boolean doDelete(File fileToDelete) throws IOException {
FileUtils.forceDelete(fileToDelete);
return true;
}
}
}
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