/* | |
* 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 453903 2006-10-07 13:47:06Z scolebourne $ | |
* @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 | |
*/ | |
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 | |
*/ | |
protected boolean doDelete(File fileToDelete) throws IOException { | |
FileUtils.forceDelete(fileToDelete); | |
return true; | |
} | |
} | |
} |