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/**
* Copyright 2011 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 com.jogamp.common.util.locks;
import java.io.File;
import jogamp.common.util.locks.SingletonInstanceFileLock;
import jogamp.common.util.locks.SingletonInstanceServerSocket;
public abstract class SingletonInstance implements Lock {
protected static final boolean DEBUG = true;
public static SingletonInstance createFileLock(final long poll_ms, final String lockFileBasename) {
return new SingletonInstanceFileLock(poll_ms, lockFileBasename);
}
public static SingletonInstance createFileLock(final long poll_ms, final File lockFile) {
return new SingletonInstanceFileLock(poll_ms, lockFile);
}
/**
* A user shall use <b>ephemeral ports</b>:
* <ul>
* <li>IANA suggests 49152 to 65535 as "dynamic and/or private ports".</li>
* <li>Many GNU/Linux kernels use 32768 to 61000.</li>
* <li>FreeBSD >= 4.6 uses the IANA port range.</li>
* <li>FreeBSD < 4.6 and BSD use ports 1024 through 4999.</li>
* <li>Microsoft Windows operating systems through Server 2003 use the range 1025 to 5000</li>
* <li>Windows Vista, Windows 7, and Server 2008 use the IANA range.</li>
* </ul>
* @param pollPeriod
* @param portNumber to be used for this single instance server socket.
*/
public static SingletonInstance createServerSocket(final long poll_ms, final int portNumber) {
return new SingletonInstanceServerSocket(poll_ms, portNumber);
}
protected SingletonInstance(final long poll_ms) {
this.poll_ms = Math.max(10, poll_ms);
}
public final long getPollPeriod() { return poll_ms; }
public abstract String getName();
@Override
public final String toString() { return getName(); }
@Override
public synchronized void lock() throws RuntimeException {
try {
do {
if(tryLock(TIMEOUT)) {
return;
}
} while ( true ) ;
} catch ( final RuntimeException ie ) {
throw new RuntimeException(ie);
}
}
@Override
public synchronized boolean tryLock(long maxwait) throws RuntimeException {
if(locked) {
return true;
}
final long t0 = System.currentTimeMillis();
int i=0;
try {
do {
final long t1 = System.currentTimeMillis();
locked = tryLockImpl();
if(locked) {
if( DEBUG ) {
final long t2 = System.currentTimeMillis();
System.err.println(infoPrefix(t2)+" +++ "+getName()+" - Locked within "+(t2-t0)+" ms, "+(i+1)+" attempts");
}
return true;
}
if( DEBUG && 0==i ) {
System.err.println(infoPrefix(System.currentTimeMillis())+" III "+getName()+" - Wait for lock");
}
Thread.sleep(poll_ms);
maxwait -= System.currentTimeMillis()-t1;
i++;
} while ( 0 < maxwait ) ;
} catch ( final InterruptedException ie ) {
final long t2 = System.currentTimeMillis();
throw new RuntimeException(infoPrefix(t2)+" EEE (1) "+getName()+" - couldn't get lock within "+(t2-t0)+" ms, "+i+" attempts", ie);
}
if( DEBUG ) {
final long t2 = System.currentTimeMillis();
System.err.println(infoPrefix(t2)+" +++ EEE (2) "+getName()+" - couldn't get lock within "+(t2-t0)+" ms, "+i+" attempts");
}
return false;
}
protected abstract boolean tryLockImpl();
@Override
public void unlock() throws RuntimeException {
final long t0 = System.currentTimeMillis();
if(locked) {
locked = !unlockImpl();
if( DEBUG ) {
final long t2 = System.currentTimeMillis();
System.err.println(infoPrefix(t2)+" --- "+getName()+" - Unlock "+ ( locked ? "failed" : "ok" ) + " within "+(t2-t0)+" ms");
}
}
}
protected abstract boolean unlockImpl();
@Override
public synchronized boolean isLocked() {
return locked;
}
protected String infoPrefix(final long currentMillis) {
return "SLOCK [T "+Thread.currentThread().getName()+" @ "+currentMillis+" ms";
}
protected String infoPrefix() {
return infoPrefix(System.currentTimeMillis());
}
private final long poll_ms;
private boolean locked = false;
}
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