/*************************************************************************
* Copyright 2009-2016 Eucalyptus Systems, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*
* Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
* CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
* additional information or have any questions.
************************************************************************/
package com.eucalyptus.util;
import java.util.concurrent.Semaphore;
/**
* Semaphore helper supporting try-with-resources use
*/
public class SemaphoreResource implements AutoCloseable {
private final Semaphore semaphore;
private final boolean acquired;
private SemaphoreResource( final Semaphore semaphore,
final boolean acquired ) {
this.semaphore = semaphore;
this.acquired = acquired;
}
public static SemaphoreResource acquire( final Semaphore semaphore ) {
semaphore.acquireUninterruptibly( );
return new SemaphoreResource( semaphore, true );
}
public boolean isAcquired( ) {
return acquired;
}
@Override
public void close( ) {
if ( isAcquired( ) ) {
semaphore.release( );
}
}
}