jtulach@71: /*
jtulach@71:  * To change this template, choose Tools | Templates
jtulach@71:  * and open the template in the editor.
jtulach@71:  */
jtulach@71: 
jtulach@330: package org.apidesign.privileged.api;
jtulach@71: 
jtulach@71: import java.util.concurrent.locks.Lock;
jtulach@71: import java.util.concurrent.locks.ReentrantLock;
jtulach@71: 
jtulach@71: /**
jtulach@71:  *
jtulach@71:  * @author Jaroslav Tulach <jaroslav.tulach@netbeans.org>
jtulach@71:  */
jtulach@330: // BEGIN: mutex.api
jtulach@71: public class Mutex {
jtulach@71:     Lock lock = new ReentrantLock();
jtulach@71:     
jtulach@71:     public Mutex() {
jtulach@71:     }
jtulach@71:     
jtulach@71:     public void readAccess(Runnable r) {
jtulach@71:         try {
jtulach@71:             lock.lock();
jtulach@71:             r.run();
jtulach@71:         } finally {
jtulach@71:             lock.unlock();
jtulach@71:         }
jtulach@71:     }
jtulach@330: // FINISH: mutex.api
jtulach@71: 
jtulach@330: // BEGIN: mutex.privileged.api
jtulach@71:     public Mutex(Privileged privileged) {
jtulach@71:         if (privileged.mutex != null) {
jtulach@71:             throw new IllegalStateException();
jtulach@71:         }
jtulach@71:         privileged.mutex = this;
jtulach@71:     }
jtulach@71:     
jtulach@71:     public static final class Privileged {
jtulach@71:         private Mutex mutex;
jtulach@71:         
jtulach@71:         public void enterReadAccess() {
jtulach@71:             mutex.lock.lock();
jtulach@71:         }
jtulach@71:         
jtulach@71:         public void exitReadAccess() {
jtulach@71:             mutex.lock.unlock();
jtulach@71:         }
jtulach@71:     }
jtulach@330: // END: mutex.privileged.api
jtulach@71: }