co.cask.common.DirUtils.java Source code

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Here is the source code for co.cask.common.DirUtils.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * Licensed 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 co.cask.common;

import com.google.common.base.Preconditions;
import com.google.common.collect.Queues;

import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.Deque;

/**
 * Copied from Google Guava as these methods are now deprecated.
 */
public final class DirUtils {

    private static final int TEMP_DIR_ATTEMPTS = 10000;

    /**
     * Utility classes should have a public constructor or a default constructor
     * hence made it private.
     */
    private DirUtils() {
    }

    /**
     * Wipes out all the a directory starting from a given directory.
     * @param directory to be cleaned
     * @throws java.io.IOException
     */
    public static void deleteDirectoryContents(File directory) throws IOException {
        Preconditions.checkArgument(directory.isDirectory(), "Not a directory: %s", directory);
        Deque<File> stack = Queues.newArrayDeque();
        stack.add(directory);

        while (!stack.isEmpty()) {
            File file = stack.peekLast();
            File[] files = file.listFiles();
            if (files == null || files.length == 0) {
                file.delete();
                stack.pollLast();
            } else {
                Collections.addAll(stack, files);
            }
        }
    }

    /**
     * Creates a temp directory inside the given base directory.
     *
     * @return the newly-created directory
     * @throws IllegalStateException if the directory could not be created
     */
    public static File createTempDir(File baseDir) {
        String baseName = System.currentTimeMillis() + "-";

        for (int counter = 0; counter < TEMP_DIR_ATTEMPTS; counter++) {
            File tempDir = new File(baseDir, baseName + counter);
            if (tempDir.mkdirs()) {
                return tempDir;
            }
        }
        throw new IllegalStateException("Failed to create directory within " + TEMP_DIR_ATTEMPTS
                + " attempts (tried " + baseName + "0 to " + baseName + (TEMP_DIR_ATTEMPTS - 1) + ')');
    }

    /**
     * Creates a directory if the directory doesn't exists.
     *
     * @param dir The directory to create
     * @return {@code true} if the directory exists or successfully created the directory.
     */
    public static boolean mkdirs(File dir) {
        // The last clause is needed so that if there are multiple threads trying to create the same directory
        // this method will still return true.
        return dir.isDirectory() || dir.mkdirs() || dir.isDirectory();
    }
}