Cleans a directory without deleting it. - Java File Path IO

Java examples for File Path IO:Directory Delete

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Description

Cleans a directory without deleting it.

Demo Code

/*//from   w w  w.  ja  va  2s.c om
 * 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 com.java2s;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.IOException;

public class Main {
    public static void main(String[] argv) throws Exception {
        File directory = new File("Main.java");
        cleanDirectory(directory);
    }

    /**
     * Cleans a directory without deleting it.
     *
     * @param directory directory to clean
     * @throws IOException in case cleaning is unsuccessful
     */
    private static void cleanDirectory(File directory) throws IOException {
        if (!directory.exists()) {
            String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        File[] files = directory.listFiles();
        if (files == null) { // null if security restricted
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (File file : files) {
            try {
                forceDelete(file);
            } catch (IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    /**
     * Deletes a file. If file is a directory, delete it and all sub-directories.
     * <p>
     * The difference between File.delete() and this method are:
     * <ul>
     * <li>A directory to be deleted does not have to be empty.</li>
     * <li>You get exceptions when a file or directory cannot be deleted.
     *      (java.io.File methods returns a boolean)</li>
     * </ul>
     *
     * @param file  file or directory to delete, must not be <code>null</code>
     * @throws NullPointerException if the directory is <code>null</code>
     * @throws FileNotFoundException if the file was not found
     * @throws IOException in case deletion is unsuccessful
     */
    public static void forceDelete(File file) throws IOException {
        if (file.isDirectory()) {
            deleteDirectory(file);
        } else {
            boolean filePresent = file.exists();
            if (!file.delete()) {
                if (!filePresent) {
                    throw new FileNotFoundException("File does not exist: "
                            + file);
                }
                String message = "Unable to delete file: " + file;
                throw new IOException(message);
            }
        }
    }

    /**
     * Deletes a directory recursively. 
     *
     * @param directory  directory to delete
     * @throws IOException in case deletion is unsuccessful
     */
    public static void deleteDirectory(File directory) throws IOException {
        if (!directory.exists()) {
            return;
        }

        if (!directory.delete()) {
            String message = "Unable to delete directory " + directory
                    + ".";
            throw new IOException(message);
        }
    }
}

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