FileLockingTest.java

/*
 * Copyright (c) 2009, Harald Kuhr
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,
 *       this list of conditions and the following disclaimer in the documentation
 *       and/or other materials provided with the distribution.
 *     * Neither the name "TwelveMonkeys" nor the names of its contributors
 *       may be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.twelvemonkeys.io;

import java.io.*;
import java.nio.channels.Channels;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;

/**
 * FileLockingTest
 *
 * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
 * @author last modified by $Author: haraldk$
 * @version $Id: FileLockingTest.java,v 1.0 May 12, 2009 7:15:38 PM haraldk Exp$
 */
public class FileLockingTest {
    public static void main(final String[] pArgs) throws IOException {
        FileChannel channel = new RandomAccessFile(pArgs[0], "rw").getChannel();
        FileLock lock = channel.tryLock(0, Long.MAX_VALUE, pArgs.length <= 1 || !"false".equalsIgnoreCase(pArgs[1])); // Shared lock for entire file

        System.out.println("lock: " + lock);

        if (lock != null) {
            System.in.read();

            InputStream stream = Channels.newInputStream(channel);
            BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
        }
        else {
            System.out.println("Already locked");
        }
    }
}