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Commons IO example source code file (FileDeleteStrategy.java)

This example Commons IO source code file (FileDeleteStrategy.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons IO tags/keywords

deletion, filedeletestrategy, filedeletestrategy, force, forcefiledeletestrategy, forcefiledeletestrategy, io, ioexception, ioexception, normal, normal, override, string

The Commons IO FileDeleteStrategy.java source code

/*
 * 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>IOExceptions 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
     * 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() 
         * if the file exists.
         *
         * @param fileToDelete  the file to delete, not null
         * @return Always returns <code>true
         * @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;
        }
    }

}

Other Commons IO examples (source code examples)

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