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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/licenses/publicdomain |
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*/ |
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|
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import java.util.*; |
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import java.util.concurrent.*; |
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import java.util.concurrent.locks.*; |
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import java.util.concurrent.atomic.*; |
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import java.io.*; |
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|
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/** |
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* A sample user extension of AbstractQueuedLongSynchronizer. |
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*/ |
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public final class LongMutex extends AbstractQueuedLongSynchronizer implements Lock, java.io.Serializable { |
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static final long LOCKED = -1L; |
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public boolean isHeldExclusively() { return getState() == LOCKED; } |
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|
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public boolean tryAcquire(long acquires) { |
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return compareAndSetState(0, LOCKED); |
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} |
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|
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public boolean tryRelease(long releases) { |
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setState(0); |
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return true; |
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} |
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public Condition newCondition() { return new ConditionObject(); } |
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|
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private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException { |
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s.defaultReadObject(); |
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setState(0); // reset to unlocked state |
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} |
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|
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public void lock() { |
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acquire(LOCKED); |
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} |
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public boolean tryLock() { |
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return tryAcquire(LOCKED); |
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} |
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public void lockInterruptibly() throws InterruptedException { |
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acquireInterruptibly(LOCKED); |
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} |
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public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException { |
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return tryAcquireNanos(LOCKED, unit.toNanos(timeout)); |
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} |
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public void unlock() { release(LOCKED); } |
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} |
