Starts at the directory given and tests to see whether it is empty
/*
* 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.
*
*/
import java.io.File;
import java.io.FileFilter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
*
* FileUtils is a collection of routines for common file system operations.
*
* @author Dan Jemiolo (danj)
*
*/
public final class FileUtils {
/**
*
* Starts at the directory given and tests to see whether it is empty; if so,
* it deletes it and moves up the directory tree, deleting empty directories
* until it finds a non-empty one.
*
* @param directory
* The first directory to test.
*
* @throws IOException
* <ul>
* <li>If the directory does not exist or the user does not have
* permission to delete it or its parents.</li>
* </ul>
*
*/
public static void pruneEmptyDirectories(File directory) throws IOException {
if (directory == null)
throw new NullPointerException("NullFile");
if (!directory.isDirectory()) {
Object[] filler = { directory.getAbsolutePath() };
String message = "NotDirectory";
throw new IllegalArgumentException(message);
}
//
// check to see if the directory is now empty and, if so, delete it
// too, moving up the tree until we find one with stuff in it
//
while (directory != null) {
File[] directoryFiles = directory.listFiles();
//
// if the directory has files, we're done
//
if (directoryFiles.length > 0)
break;
if (!directory.delete()) {
Object[] filler = { directory.getAbsolutePath() };
String message = "DeleteFailed";
throw new IOException(message);
}
//
// go up the tree
//
directory = directory.getParentFile();
}
}
/**
*
* The application's current working directory.
*
*/
public static final File CURRENT_DIR = new File(".");
/**
*
* This is a convenience method that calls remove(File, boolean) with the
* second parameter set to "false" (doesn't prune empty directories).
*
* @see #remove(File, boolean)
*
*/
public static void remove(File file) throws IOException {
remove(file, false);
}
/**
*
* @param file
* The file or directory to delete.
*
* @param pruneEmptyDirectories
* True if the deletion results in an empty parent directory. If set
* to true, this method will traverse up the directory tree, deleting
* directories that are made empty by the deletion.
*
* @throws IOException
* <ul>
* <li>If there was an error trying to remove the file or
* directory. The file system may be in an inconsistent state when
* the exception is thrown (directories may be partially deleted,
* etc.).</li>
* </ul>
*
*/
public static void remove(File file, boolean pruneEmptyDirectories) throws IOException {
if (file == null)
throw new NullPointerException("NullFile");
if (file.isDirectory())
removeDirectory(file);
else
removeFile(file);
if (pruneEmptyDirectories)
pruneEmptyDirectories(file.getParentFile());
}
private static void removeDirectory(File directory) throws IOException {
File[] files = directory.listFiles();
//
// for all items in the directory...
//
for (int n = 0; n < files.length; ++n) {
File nextFile = files[n];
//
// if it's a directory, delete sub-directories and files before
// removing the empty directory
//
if (nextFile.isDirectory())
removeDirectory(nextFile);
//
// otherwise just delete the file - do NOT prune the directory
// in advance
//
else
removeFile(nextFile);
}
//
// now that everything's gone, delete the specified directory
//
if (!directory.delete()) {
Object[] filler = { directory.getAbsolutePath() };
String message = "DeleteFailed";
throw new IOException(message);
}
}
private static void removeFile(File file) throws IOException {
//
// make sure the file exists, then delete it
//
if (!file.exists())
throw new FileNotFoundException(file.getAbsolutePath());
if (!file.delete()) {
Object[] filler = { file.getAbsolutePath() };
String message = "DeleteFailed";
throw new IOException(message);
}
}
}
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