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/**
* Copyright 2010 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``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 JogAmp Community 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.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package jogamp.common.util.locks;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileLock;
import com.jogamp.common.util.locks.SingletonInstance;
public class SingletonInstanceFileLock extends SingletonInstance {
static final String temp_file_path;
static {
String s = null;
try {
File tmpFile = File.createTempFile("TEST", "tst");
String absTmpFile = tmpFile.getCanonicalPath();
tmpFile.delete();
s = absTmpFile.substring(0, absTmpFile.lastIndexOf(File.separator));
} catch (IOException ex) {
ex.printStackTrace();
}
temp_file_path = s;
}
public static String getCanonicalTempPath() {
return temp_file_path;
}
public static String getCanonicalTempLockFilePath(String basename) {
return getCanonicalTempPath() + File.separator + basename;
}
public SingletonInstanceFileLock(long poll_ms, String lockFileBasename) {
super(poll_ms);
file = new File ( getCanonicalTempLockFilePath ( lockFileBasename ) );
setupFileCleanup();
}
public SingletonInstanceFileLock(long poll_ms, File lockFile) {
super(poll_ms);
file = lockFile ;
setupFileCleanup();
}
public final String getName() { return file.getPath(); }
private void setupFileCleanup() {
file.deleteOnExit();
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() {
unlock();
}
});
}
@Override
protected boolean tryLockImpl() {
try {
randomAccessFile = new RandomAccessFile(file, "rw");
fileLock = randomAccessFile.getChannel().tryLock();
if (fileLock != null) {
return true;
}
} catch (Exception e) {
System.err.println("SLOCK "+System.currentTimeMillis()+" EEE "+getName()+" - Unable to create and/or lock file");
e.printStackTrace();
}
return false;
}
@Override
protected boolean unlockImpl() {
try {
if(null != fileLock) {
fileLock.release();
fileLock = null;
}
if(null != randomAccessFile) {
randomAccessFile.close();
randomAccessFile = null;
}
if(null != file) {
file.delete();
}
return true;
} catch (Exception e) {
System.err.println("SLOCK "+System.currentTimeMillis()+" EEE "+getName()+" - Unable to remove lock file");
e.printStackTrace();
} finally {
fileLock = null;
randomAccessFile = null;
}
return false;
}
private final File file;
private RandomAccessFile randomAccessFile = null;
private FileLock fileLock = null;
}
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