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java.lang.Objectedu.emory.mathcs.util.concurrent.ReentrantNamedLock
Implements a reentrant named lock that can be shared between different parts of the application without sharing the lock object, by using a common name.
Constructor Summary | |
ReentrantNamedLock(java.lang.Object name)
Create a new ReentrantRemoteLock instance. |
Method Summary | |
boolean |
equals(java.lang.Object other)
Two named locks are equal if their names are equal. |
int |
hashCode()
|
void |
lock()
Acquires the lock. If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until the lock has been acquired. Implementation Considerations A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation. |
void |
lockInterruptibly()
Acquires the lock unless the current thread is interrupted. Acquires the lock if it is available and returns immediately. If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:
If the current thread:
InterruptedException is thrown and the current thread's
interrupted status is cleared.
Implementation Considerations The ability to interrupt a lock acquisition in some implementations may not be possible, and if possible may be an expensive operation. The programmer should be aware that this may be the case. An implementation should document when this is the case. An implementation can favor responding to an interrupt over normal method return. A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation. |
Condition |
newCondition()
Returns a new Condition instance that is bound to this
instance.
Before waiting on the condition the lock must be held by the
current thread.
A call to Implementation Considerations The exact operation of the |
boolean |
tryLock()
Acquires the lock only if it is free at the time of invocation. Acquires the lock if it is available and returns immediately with the value . If the lock is not available then this method will return immediately with the value . A typical usage idiom for this method would be: Lock lock = ...; if (lock.tryLock()) { try { // manipulate protected state } finally { lock.unlock(); } } else { // perform alternative actions }This usage ensures that the lock is unlocked if it was acquired, and doesn't try to unlock if the lock was not acquired. |
boolean |
tryLock(long timeout,
TimeUnit unit)
Acquires the lock if it is free within the given waiting time and the current thread has not been interrupted. If the lock is available this method returns immediately with the value . If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:
If the lock is acquired then the value is returned. If the current thread:
InterruptedException is thrown and the current thread's
interrupted status is cleared.
If the specified waiting time elapses then the value is returned. If the time is less than or equal to zero, the method will not wait at all. Implementation Considerations The ability to interrupt a lock acquisition in some implementations may not be possible, and if possible may be an expensive operation. The programmer should be aware that this may be the case. An implementation should document when this is the case. An implementation can favor responding to an interrupt over normal method return, or reporting a timeout. A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation. |
void |
unlock()
Releases the lock. Implementation Considerations A implementation will usually impose restrictions on which thread can release a lock (typically only the holder of the lock can release it) and may throw an (unchecked) exception if the restriction is violated. Any restrictions and the exception type must be documented by that implementation. |
Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public ReentrantNamedLock(java.lang.Object name)
Method Detail |
public void lock()
If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until the lock has been acquired.
Implementation Considerations
A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation.
lock
in interface Lock
public boolean tryLock()
Acquires the lock if it is available and returns immediately with the value . If the lock is not available then this method will return immediately with the value .
A typical usage idiom for this method would be:
Lock lock = ...; if (lock.tryLock()) { try { // manipulate protected state } finally { lock.unlock(); } } else { // perform alternative actions }This usage ensures that the lock is unlocked if it was acquired, and doesn't try to unlock if the lock was not acquired.
tryLock
in interface Lock
public void lockInterruptibly() throws java.lang.InterruptedException
Acquires the lock if it is available and returns immediately.
If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:
If the current thread:
InterruptedException
is thrown and the current thread's
interrupted status is cleared.
Implementation Considerations
The ability to interrupt a lock acquisition in some implementations may not be possible, and if possible may be an expensive operation. The programmer should be aware that this may be the case. An implementation should document when this is the case.
An implementation can favor responding to an interrupt over normal method return.
A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation.
lockInterruptibly
in interface Lock
java.lang.InterruptedException
- if the current thread is
interrupted while acquiring the lock (and interruption
of lock acquisition is supported).public boolean tryLock(long timeout, TimeUnit unit) throws java.lang.InterruptedException
If the lock is available this method returns immediately with the value . If the lock is not available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:
If the lock is acquired then the value is returned.
If the current thread:
InterruptedException
is thrown and the current thread's
interrupted status is cleared.
If the specified waiting time elapses then the value is returned. If the time is less than or equal to zero, the method will not wait at all.
Implementation Considerations
The ability to interrupt a lock acquisition in some implementations may not be possible, and if possible may be an expensive operation. The programmer should be aware that this may be the case. An implementation should document when this is the case.
An implementation can favor responding to an interrupt over normal method return, or reporting a timeout.
A implementation may be able to detect erroneous use of the lock, such as an invocation that would cause deadlock, and may throw an (unchecked) exception in such circumstances. The circumstances and the exception type must be documented by that implementation.
tryLock
in interface Lock
timeout
- the maximum time to wait for the lockunit
- the time unit of the argument
java.lang.InterruptedException
- if the current thread is interrupted
while acquiring the lock (and interruption of lock
acquisition is supported)public void unlock()
Implementation Considerations
A implementation will usually impose restrictions on which thread can release a lock (typically only the holder of the lock can release it) and may throw an (unchecked) exception if the restriction is violated. Any restrictions and the exception type must be documented by that implementation.
unlock
in interface Lock
public Condition newCondition()
Condition
instance that is bound to this
instance.
Before waiting on the condition the lock must be held by the
current thread.
A call to Condition.await()
will atomically release the lock
before waiting and re-acquire the lock before the wait returns.
Implementation Considerations
The exact operation of the Condition
instance depends on
the implementation and must be documented by that
implementation.
newCondition
in interface Lock
Condition
instance for this instancepublic int hashCode()
public boolean equals(java.lang.Object other)
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