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Diffstat (limited to 'src/actors/scala/actors/threadpool/locks/ReentrantLock.java')
-rw-r--r-- | src/actors/scala/actors/threadpool/locks/ReentrantLock.java | 959 |
1 files changed, 0 insertions, 959 deletions
diff --git a/src/actors/scala/actors/threadpool/locks/ReentrantLock.java b/src/actors/scala/actors/threadpool/locks/ReentrantLock.java deleted file mode 100644 index b42ddd611b..0000000000 --- a/src/actors/scala/actors/threadpool/locks/ReentrantLock.java +++ /dev/null @@ -1,959 +0,0 @@ -/* - * Written by Doug Lea with assistance from members of JCP JSR-166 - * Expert Group and released to the public domain, as explained at - * http://creativecommons.org/licenses/publicdomain - */ - -package scala.actors.threadpool.locks; - -import java.util.Collection; -import scala.actors.threadpool.*; -import scala.actors.threadpool.helpers.*; - -/** - * A reentrant mutual exclusion {@link Lock} with the same basic - * behavior and semantics as the implicit monitor lock accessed using - * {@code synchronized} methods and statements, but with extended - * capabilities. - * - * <p>A {@code ReentrantLock} is <em>owned</em> by the thread last - * successfully locking, but not yet unlocking it. A thread invoking - * {@code lock} will return, successfully acquiring the lock, when - * the lock is not owned by another thread. The method will return - * immediately if the current thread already owns the lock. This can - * be checked using methods {@link #isHeldByCurrentThread}, and {@link - * #getHoldCount}. - * - * <p>The constructor for this class accepts an optional - * <em>fairness</em> parameter. When set {@code true}, under - * contention, locks favor granting access to the longest-waiting - * thread. Otherwise this lock does not guarantee any particular - * access order. Programs using fair locks accessed by many threads - * may display lower overall throughput (i.e., are slower; often much - * slower) than those using the default setting, but have smaller - * variances in times to obtain locks and guarantee lack of - * starvation. Note however, that fairness of locks does not guarantee - * fairness of thread scheduling. Thus, one of many threads using a - * fair lock may obtain it multiple times in succession while other - * active threads are not progressing and not currently holding the - * lock. - * Also note that the untimed {@link #tryLock() tryLock} method does not - * honor the fairness setting. It will succeed if the lock - * is available even if other threads are waiting. - * - * <p>It is recommended practice to <em>always</em> immediately - * follow a call to {@code lock} with a {@code try} block, most - * typically in a before/after construction such as: - * - * <pre> - * class X { - * private final ReentrantLock lock = new ReentrantLock(); - * // ... - * - * public void m() { - * lock.lock(); // block until condition holds - * try { - * // ... method body - * } finally { - * lock.unlock() - * } - * } - * } - * </pre> - * - * <p>In addition to implementing the {@link Lock} interface, this - * class defines methods {@code isLocked} and - * {@code getLockQueueLength}, as well as some associated - * {@code protected} access methods that may be useful for - * instrumentation and monitoring. - * - * <p>Serialization of this class behaves in the same way as built-in - * locks: a deserialized lock is in the unlocked state, regardless of - * its state when serialized. - * - * <p>This lock supports a maximum of 2147483647 recursive locks by - * the same thread. Attempts to exceed this limit result in - * {@link Error} throws from locking methods. - * - * @since 1.5 - * @author Doug Lea - * @author Dawid Kurzyniec - */ -public class ReentrantLock implements Lock, java.io.Serializable, - CondVar.ExclusiveLock { - private static final long serialVersionUID = 7373984872572414699L; - - private final Sync sync; - - /** - * Base of synchronization control for this lock. Subclassed - * into fair and nonfair versions below. - */ - static abstract class Sync implements java.io.Serializable { - private static final long serialVersionUID = -5179523762034025860L; - - protected transient Thread owner_ = null; - protected transient int holds_ = 0; - - protected Sync() {} - - /** - * Performs {@link Lock#lock}. The main reason for subclassing - * is to allow fast path for nonfair version. - */ - public abstract void lock(); - - public abstract void lockInterruptibly() throws InterruptedException; - - final void incHolds() { - int nextHolds = ++holds_; - if (nextHolds < 0) - throw new Error("Maximum lock count exceeded"); - holds_ = nextHolds; - } - - public boolean tryLock() { - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return true; - } - else if (caller == owner_) { - incHolds(); - return true; - } - } - return false; - } - - public abstract boolean tryLock(long nanos) throws InterruptedException; - - public abstract void unlock(); - - public synchronized int getHoldCount() { - return isHeldByCurrentThread() ? holds_ : 0; - } - - public synchronized boolean isHeldByCurrentThread() { - return holds_ > 0 && Thread.currentThread() == owner_; - } - - public synchronized boolean isLocked() { - return owner_ != null; - } - - public abstract boolean isFair(); - - protected synchronized Thread getOwner() { - return owner_; - } - - public boolean hasQueuedThreads() { - throw new UnsupportedOperationException("Use FAIR version"); - } - - public int getQueueLength() { - throw new UnsupportedOperationException("Use FAIR version"); - } - - public Collection getQueuedThreads() { - throw new UnsupportedOperationException("Use FAIR version"); - } - - public boolean isQueued(Thread thread) { - throw new UnsupportedOperationException("Use FAIR version"); - } - } - - /** - * Sync object for non-fair locks - */ - final static class NonfairSync extends Sync { - private static final long serialVersionUID = 7316153563782823691L; - - NonfairSync() {} - - /** - * Performs lock. Try immediate barge, backing up to normal - * acquire on failure. - */ - public void lock() { - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return; - } - else if (caller == owner_) { - incHolds(); - return; - } - else { - boolean wasInterrupted = Thread.interrupted(); - try { - while (true) { - try { - wait(); - } - catch (InterruptedException e) { - wasInterrupted = true; - // no need to notify; if we were signalled, we - // will act as signalled, ignoring the - // interruption - } - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return; - } - } - } - finally { - if (wasInterrupted) Thread.currentThread().interrupt(); - } - } - } - } - - public void lockInterruptibly() throws InterruptedException { - if (Thread.interrupted()) throw new InterruptedException(); - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return; - } - else if (caller == owner_) { - incHolds(); - return; - } - else { - try { - do { wait(); } while (owner_ != null); - owner_ = caller; - holds_ = 1; - return; - } - catch (InterruptedException ex) { - if (owner_ == null) notify(); - throw ex; - } - } - } - } - - public boolean tryLock(long nanos) throws InterruptedException { - if (Thread.interrupted()) throw new InterruptedException(); - Thread caller = Thread.currentThread(); - - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return true; - } - else if (caller == owner_) { - incHolds(); - return true; - } - else if (nanos <= 0) - return false; - else { - long deadline = Utils.nanoTime() + nanos; - try { - for (; ; ) { - TimeUnit.NANOSECONDS.timedWait(this, nanos); - if (caller == owner_) { - incHolds(); - return true; - } - else if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return true; - } - else { - nanos = deadline - Utils.nanoTime(); - if (nanos <= 0) - return false; - } - } - } - catch (InterruptedException ex) { - if (owner_ == null) notify(); - throw ex; - } - } - } - } - - public synchronized void unlock() { - if (Thread.currentThread() != owner_) - throw new IllegalMonitorStateException("Not owner"); - - if (--holds_ == 0) { - owner_ = null; - notify(); - } - } - - public final boolean isFair() { - return false; - } - } - - /** - * Sync object for fair locks - */ - final static class FairSync extends Sync implements WaitQueue.QueuedSync { - private static final long serialVersionUID = -3000897897090466540L; - - private transient WaitQueue wq_ = new FIFOWaitQueue(); - - FairSync() {} - - public synchronized boolean recheck(WaitQueue.WaitNode node) { - Thread caller = Thread.currentThread(); - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return true; - } - else if (caller == owner_) { - incHolds(); - return true; - } - wq_.insert(node); - return false; - } - - public synchronized void takeOver(WaitQueue.WaitNode node) { - // assert (holds_ == 1 && owner_ == Thread.currentThread() - owner_ = node.getOwner(); - } - - public void lock() { - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return; - } - else if (caller == owner_) { - incHolds(); - return; - } - } - WaitQueue.WaitNode n = new WaitQueue.WaitNode(); - n.doWaitUninterruptibly(this); - } - - public void lockInterruptibly() throws InterruptedException { - if (Thread.interrupted()) throw new InterruptedException(); - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return; - } - else if (caller == owner_) { - incHolds(); - return; - } - } - WaitQueue.WaitNode n = new WaitQueue.WaitNode(); - n.doWait(this); - } - - public boolean tryLock(long nanos) throws InterruptedException { - if (Thread.interrupted()) throw new InterruptedException(); - Thread caller = Thread.currentThread(); - synchronized (this) { - if (owner_ == null) { - owner_ = caller; - holds_ = 1; - return true; - } - else if (caller == owner_) { - incHolds(); - return true; - } - } - WaitQueue.WaitNode n = new WaitQueue.WaitNode(); - return n.doTimedWait(this, nanos); - } - - protected synchronized WaitQueue.WaitNode getSignallee(Thread caller) { - if (caller != owner_) - throw new IllegalMonitorStateException("Not owner"); - // assert (holds_ > 0) - if (holds_ >= 2) { // current thread will keep the lock - --holds_; - return null; - } - // assert (holds_ == 1) - WaitQueue.WaitNode w = wq_.extract(); - if (w == null) { // if none, clear for new arrivals - owner_ = null; - holds_ = 0; - } - return w; - } - - public void unlock() { - Thread caller = Thread.currentThread(); - for (;;) { - WaitQueue.WaitNode w = getSignallee(caller); - if (w == null) return; // no one to signal - if (w.signal(this)) return; // notify if still waiting, else skip - } - } - - public final boolean isFair() { - return true; - } - - public synchronized boolean hasQueuedThreads() { - return wq_.hasNodes(); - } - - public synchronized int getQueueLength() { - return wq_.getLength(); - } - - public synchronized Collection getQueuedThreads() { - return wq_.getWaitingThreads(); - } - - public synchronized boolean isQueued(Thread thread) { - return wq_.isWaiting(thread); - } - - private void readObject(java.io.ObjectInputStream in) - throws java.io.IOException, ClassNotFoundException { - in.defaultReadObject(); - synchronized (this) { - wq_ = new FIFOWaitQueue(); - } - } - } - - /** - * Creates an instance of {@code ReentrantLock}. - * This is equivalent to using {@code ReentrantLock(false)}. - */ - public ReentrantLock() { - sync = new NonfairSync(); - } - - /** - * Creates an instance of {@code ReentrantLock} with the - * given fairness policy. - * - * @param fair {@code true} if this lock should use a fair ordering policy - */ - public ReentrantLock(boolean fair) { - sync = (fair)? (Sync)new FairSync() : new NonfairSync(); - } - - - /** - * Acquires the lock. - * - * <p>Acquires the lock if it is not held by another thread and returns - * immediately, setting the lock hold count to one. - * - * <p>If the current thread already holds the lock then the hold - * count is incremented by one and the method returns immediately. - * - * <p>If the lock is held by another thread then the - * current thread becomes disabled for thread scheduling - * purposes and lies dormant until the lock has been acquired, - * at which time the lock hold count is set to one. - */ - public void lock() { - sync.lock(); - } - - /** - * Acquires the lock unless the current thread is - * {@linkplain Thread#interrupt interrupted}. - * - * <p>Acquires the lock if it is not held by another thread and returns - * immediately, setting the lock hold count to one. - * - * <p>If the current thread already holds this lock then the hold count - * is incremented by one and the method returns immediately. - * - * <p>If the lock is held by another thread then the - * current thread becomes disabled for thread scheduling - * purposes and lies dormant until one of two things happens: - * - * <ul> - * - * <li>The lock is acquired by the current thread; or - * - * <li>Some other thread {@linkplain Thread#interrupt interrupts} the - * current thread. - * - * </ul> - * - * <p>If the lock is acquired by the current thread then the lock hold - * count is set to one. - * - * <p>If the current thread: - * - * <ul> - * - * <li>has its interrupted status set on entry to this method; or - * - * <li>is {@linkplain Thread#interrupt interrupted} while acquiring - * the lock, - * - * </ul> - * - * then {@link InterruptedException} is thrown and the current thread's - * interrupted status is cleared. - * - * <p>In this implementation, as this method is an explicit - * interruption point, preference is given to responding to the - * interrupt over normal or reentrant acquisition of the lock. - * - * @throws InterruptedException if the current thread is interrupted - */ - public void lockInterruptibly() throws InterruptedException { - sync.lockInterruptibly(); - } - - /** - * Acquires the lock only if it is not held by another thread at the time - * of invocation. - * - * <p>Acquires the lock if it is not held by another thread and - * returns immediately with the value {@code true}, setting the - * lock hold count to one. Even when this lock has been set to use a - * fair ordering policy, a call to {@code tryLock()} <em>will</em> - * immediately acquire the lock if it is available, whether or not - * other threads are currently waiting for the lock. - * This "barging" behavior can be useful in certain - * circumstances, even though it breaks fairness. If you want to honor - * the fairness setting for this lock, then use - * {@link #tryLock(long, TimeUnit) tryLock(0, TimeUnit.SECONDS) } - * which is almost equivalent (it also detects interruption). - * - * <p> If the current thread already holds this lock then the hold - * count is incremented by one and the method returns {@code true}. - * - * <p>If the lock is held by another thread then this method will return - * immediately with the value {@code false}. - * - * @return {@code true} if the lock was free and was acquired by the - * current thread, or the lock was already held by the current - * thread; and {@code false} otherwise - */ - public boolean tryLock() { - return sync.tryLock(); - } - - /** - * Acquires the lock if it is not held by another thread within the given - * waiting time and the current thread has not been - * {@linkplain Thread#interrupt interrupted}. - * - * <p>Acquires the lock if it is not held by another thread and returns - * immediately with the value {@code true}, setting the lock hold count - * to one. If this lock has been set to use a fair ordering policy then - * an available lock <em>will not</em> be acquired if any other threads - * are waiting for the lock. This is in contrast to the {@link #tryLock()} - * method. If you want a timed {@code tryLock} that does permit barging on - * a fair lock then combine the timed and un-timed forms together: - * - * <pre>if (lock.tryLock() || lock.tryLock(timeout, unit) ) { ... } - * </pre> - * - * <p>If the current thread - * already holds this lock then the hold count is incremented by one and - * the method returns {@code true}. - * - * <p>If the lock is held by another thread then the - * current thread becomes disabled for thread scheduling - * purposes and lies dormant until one of three things happens: - * - * <ul> - * - * <li>The lock is acquired by the current thread; or - * - * <li>Some other thread {@linkplain Thread#interrupt interrupts} - * the current thread; or - * - * <li>The specified waiting time elapses - * - * </ul> - * - * <p>If the lock is acquired then the value {@code true} is returned and - * the lock hold count is set to one. - * - * <p>If the current thread: - * - * <ul> - * - * <li>has its interrupted status set on entry to this method; or - * - * <li>is {@linkplain Thread#interrupt interrupted} while - * acquiring the lock, - * - * </ul> - * then {@link InterruptedException} is thrown and the current thread's - * interrupted status is cleared. - * - * <p>If the specified waiting time elapses then the value {@code false} - * is returned. If the time is less than or equal to zero, the method - * will not wait at all. - * - * <p>In this implementation, as this method is an explicit - * interruption point, preference is given to responding to the - * interrupt over normal or reentrant acquisition of the lock, and - * over reporting the elapse of the waiting time. - * - * @param timeout the time to wait for the lock - * @param unit the time unit of the timeout argument - * @return {@code true} if the lock was free and was acquired by the - * current thread, or the lock was already held by the current - * thread; and {@code false} if the waiting time elapsed before - * the lock could be acquired - * @throws InterruptedException if the current thread is interrupted - * @throws NullPointerException if the time unit is null - * - */ - public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException { - return sync.tryLock(unit.toNanos(timeout)); - } - - /** - * Attempts to release this lock. - * - * <p>If the current thread is the holder of this lock then the hold - * count is decremented. If the hold count is now zero then the lock - * is released. If the current thread is not the holder of this - * lock then {@link IllegalMonitorStateException} is thrown. - * - * @throws IllegalMonitorStateException if the current thread does not - * hold this lock - */ - public void unlock() { - sync.unlock(); - } - - /** - * Returns a {@link Condition} instance for use with this - * {@link Lock} instance. - * - * <p>The returned {@link Condition} instance supports the same - * usages as do the {@link Object} monitor methods ({@link - * Object#wait() wait}, {@link Object#notify notify}, and {@link - * Object#notifyAll notifyAll}) when used with the built-in - * monitor lock. - * - * <ul> - * - * <li>If this lock is not held when any of the {@link Condition} - * {@linkplain Condition#await() waiting} or {@linkplain - * Condition#signal signalling} methods are called, then an {@link - * IllegalMonitorStateException} is thrown. - * - * <li>When the condition {@linkplain Condition#await() waiting} - * methods are called the lock is released and, before they - * return, the lock is reacquired and the lock hold count restored - * to what it was when the method was called. - * - * <li>If a thread is {@linkplain Thread#interrupt interrupted} - * while waiting then the wait will terminate, an {@link - * InterruptedException} will be thrown, and the thread's - * interrupted status will be cleared. - * - * <li> Waiting threads are signalled in FIFO order. - * - * <li>The ordering of lock reacquisition for threads returning - * from waiting methods is the same as for threads initially - * acquiring the lock, which is in the default case not specified, - * but for <em>fair</em> locks favors those threads that have been - * waiting the longest. - * - * </ul> - * - * @return the Condition object - */ - public Condition newCondition() { - return isFair() ? (Condition)new FIFOCondVar(this) : new CondVar(this); - } - - /** - * Queries the number of holds on this lock by the current thread. - * - * <p>A thread has a hold on a lock for each lock action that is not - * matched by an unlock action. - * - * <p>The hold count information is typically only used for testing and - * debugging purposes. For example, if a certain section of code should - * not be entered with the lock already held then we can assert that - * fact: - * - * <pre> - * class X { - * ReentrantLock lock = new ReentrantLock(); - * // ... - * public void m() { - * assert lock.getHoldCount() == 0; - * lock.lock(); - * try { - * // ... method body - * } finally { - * lock.unlock(); - * } - * } - * } - * </pre> - * - * @return the number of holds on this lock by the current thread, - * or zero if this lock is not held by the current thread - */ - public int getHoldCount() { - return sync.getHoldCount(); - } - - /** - * Queries if this lock is held by the current thread. - * - * <p>Analogous to the {@link Thread#holdsLock} method for built-in - * monitor locks, this method is typically used for debugging and - * testing. For example, a method that should only be called while - * a lock is held can assert that this is the case: - * - * <pre> - * class X { - * ReentrantLock lock = new ReentrantLock(); - * // ... - * - * public void m() { - * assert lock.isHeldByCurrentThread(); - * // ... method body - * } - * } - * </pre> - * - * <p>It can also be used to ensure that a reentrant lock is used - * in a non-reentrant manner, for example: - * - * <pre> - * class X { - * ReentrantLock lock = new ReentrantLock(); - * // ... - * - * public void m() { - * assert !lock.isHeldByCurrentThread(); - * lock.lock(); - * try { - * // ... method body - * } finally { - * lock.unlock(); - * } - * } - * } - * </pre> - * - * @return {@code true} if current thread holds this lock and - * {@code false} otherwise - */ - public boolean isHeldByCurrentThread() { - return sync.isHeldByCurrentThread(); - } - - /** - * Queries if this lock is held by any thread. This method is - * designed for use in monitoring of the system state, - * not for synchronization control. - * - * @return {@code true} if any thread holds this lock and - * {@code false} otherwise - */ - public boolean isLocked() { - return sync.isLocked(); - } - - /** - * Returns {@code true} if this lock has fairness set true. - * - * @return {@code true} if this lock has fairness set true - */ - public final boolean isFair() { - return sync.isFair(); - } - - /** - * Returns the thread that currently owns this lock, or - * {@code null} if not owned. When this method is called by a - * thread that is not the owner, the return value reflects a - * best-effort approximation of current lock status. For example, - * the owner may be momentarily {@code null} even if there are - * threads trying to acquire the lock but have not yet done so. - * This method is designed to facilitate construction of - * subclasses that provide more extensive lock monitoring - * facilities. - * - * @return the owner, or {@code null} if not owned - */ - protected Thread getOwner() { - return sync.getOwner(); - } - - /** - * Queries whether any threads are waiting to acquire this lock. Note that - * because cancellations may occur at any time, a {@code true} - * return does not guarantee that any other thread will ever - * acquire this lock. This method is designed primarily for use in - * monitoring of the system state. - * - * @return {@code true} if there may be other threads waiting to - * acquire the lock - */ - public final boolean hasQueuedThreads() { - return sync.hasQueuedThreads(); - } - - - /** - * Queries whether the given thread is waiting to acquire this - * lock. Note that because cancellations may occur at any time, a - * {@code true} return does not guarantee that this thread - * will ever acquire this lock. This method is designed primarily for use - * in monitoring of the system state. - * - * @param thread the thread - * @return {@code true} if the given thread is queued waiting for this lock - * @throws NullPointerException if the thread is null - */ - public final boolean hasQueuedThread(Thread thread) { - return sync.isQueued(thread); - } - - - /** - * Returns an estimate of the number of threads waiting to - * acquire this lock. The value is only an estimate because the number of - * threads may change dynamically while this method traverses - * internal data structures. This method is designed for use in - * monitoring of the system state, not for synchronization - * control. - * - * @return the estimated number of threads waiting for this lock - */ - public final int getQueueLength() { - return sync.getQueueLength(); - } - - /** - * Returns a collection containing threads that may be waiting to - * acquire this lock. Because the actual set of threads may change - * dynamically while constructing this result, the returned - * collection is only a best-effort estimate. The elements of the - * returned collection are in no particular order. This method is - * designed to facilitate construction of subclasses that provide - * more extensive monitoring facilities. - * - * @return the collection of threads - */ - protected Collection getQueuedThreads() { - return sync.getQueuedThreads(); - } - - /** - * Queries whether any threads are waiting on the given condition - * associated with this lock. Note that because timeouts and - * interrupts may occur at any time, a {@code true} return does - * not guarantee that a future {@code signal} will awaken any - * threads. This method is designed primarily for use in - * monitoring of the system state. - * - * @param condition the condition - * @return {@code true} if there are any waiting threads - * @throws IllegalMonitorStateException if this lock is not held - * @throws IllegalArgumentException if the given condition is - * not associated with this lock - * @throws NullPointerException if the condition is null - */ - public boolean hasWaiters(Condition condition) { - return asCondVar(condition).hasWaiters(); - } - - /** - * Returns an estimate of the number of threads waiting on the - * given condition associated with this lock. Note that because - * timeouts and interrupts may occur at any time, the estimate - * serves only as an upper bound on the actual number of waiters. - * This method is designed for use in monitoring of the system - * state, not for synchronization control. - * - * @param condition the condition - * @return the estimated number of waiting threads - * @throws IllegalMonitorStateException if this lock is not held - * @throws IllegalArgumentException if the given condition is - * not associated with this lock - * @throws NullPointerException if the condition is null - */ - public int getWaitQueueLength(Condition condition) { - return asCondVar(condition).getWaitQueueLength(); - } - - /** - * Returns a collection containing those threads that may be - * waiting on the given condition associated with this lock. - * Because the actual set of threads may change dynamically while - * constructing this result, the returned collection is only a - * best-effort estimate. The elements of the returned collection - * are in no particular order. This method is designed to - * facilitate construction of subclasses that provide more - * extensive condition monitoring facilities. - * - * @param condition the condition - * @return the collection of threads - * @throws IllegalMonitorStateException if this lock is not held - * @throws IllegalArgumentException if the given condition is - * not associated with this lock - * @throws NullPointerException if the condition is null - */ - protected Collection getWaitingThreads(Condition condition) { - return asCondVar(condition).getWaitingThreads(); - } - - /** - * Returns a string identifying this lock, as well as its lock state. - * The state, in brackets, includes either the String {@code "Unlocked"} - * or the String {@code "Locked by"} followed by the - * {@linkplain Thread#getName name} of the owning thread. - * - * @return a string identifying this lock, as well as its lock state - */ - public String toString() { - Thread o = getOwner(); - return super.toString() + ((o == null) ? - "[Unlocked]" : - "[Locked by thread " + o.getName() + "]"); - } - - private CondVar asCondVar(Condition condition) { - if (condition == null) - throw new NullPointerException(); - if (!(condition instanceof CondVar)) - throw new IllegalArgumentException("not owner"); - CondVar condVar = (CondVar)condition; - if (condVar.lock != this) - throw new IllegalArgumentException("not owner"); - return condVar; - } -} |