java.lang.Object | |
↳ | java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock |
The lock returned by method readLock()
.
Protected Constructors | |||||||||||
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Constructor for use by subclasses
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Public Methods | |||||||||||
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Acquires the read lock.
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Acquires the read lock unless the current thread is
interrupted . | |||||||||||
Throws
UnsupportedOperationException because
ReadLocks do not support conditions. | |||||||||||
Returns a string identifying this lock, as well as its lock state.
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Acquires the read lock only if the write lock is not held by
another thread at the time of invocation.
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Acquires the read lock if the write lock is not held by
another thread within the given waiting time and the
current thread has not been
interrupted . | |||||||||||
Attempts to release this lock.
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Inherited Methods | |||||||||||
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From class
java.lang.Object
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From interface
java.util.concurrent.locks.Lock
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Constructor for use by subclasses
lock | the outer lock object |
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NullPointerException | if the lock is null |
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Acquires the read lock.
Acquires the read lock if the write lock is not held by another thread and returns immediately.
If the write lock is held by another thread then the current thread becomes disabled for thread scheduling purposes and lies dormant until the read lock has been acquired.
Acquires the read lock unless the current thread is
interrupted
.
Acquires the read lock if the write lock is not held by another thread and returns immediately.
If the write 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:
interrupts
the current thread.
If the current thread:
interrupted
while
acquiring the read lock,
InterruptedException
is thrown and the current
thread's interrupted status is cleared.
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.
InterruptedException | if the current thread is interrupted |
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Throws UnsupportedOperationException
because
ReadLocks
do not support conditions.
Condition
instance for this Lock
instanceUnsupportedOperationException | always |
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Returns a string identifying this lock, as well as its lock state.
The state, in brackets, includes the String "Read locks ="
followed by the number of held read locks.
Acquires the read lock only if the write lock is not held by another thread at the time of invocation.
Acquires the read lock if the write lock is not held by
another thread and returns immediately with the value
true
. Even when this lock has been set to use a
fair ordering policy, a call to tryLock()
will immediately acquire the read lock if it is
available, whether or not other threads are currently
waiting for the read 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 tryLock(0, TimeUnit.SECONDS)
which is almost equivalent
(it also detects interruption).
If the write lock is held by another thread then
this method will return immediately with the value
false
.
true
if the read lock was acquired
Acquires the read lock if the write lock is not held by
another thread within the given waiting time and the
current thread has not been interrupted
.
Acquires the read lock if the write lock is not held by
another thread and returns immediately with the value
true
. If this lock has been set to use a fair
ordering policy then an available lock will not be
acquired if any other threads are waiting for the
lock. This is in contrast to the tryLock()
method. If you want a timed tryLock
that does
permit barging on a fair lock then combine the timed and
un-timed forms together:
if (lock.tryLock() ||
lock.tryLock(timeout, unit)) {
...
}
If the write 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:
interrupts
the current thread; or
If the read lock is acquired then the value true
is
returned.
If the current thread:
interrupted
while
acquiring the read lock,
InterruptedException
is thrown and the
current thread's interrupted status is cleared.
If the specified waiting time elapses then the value
false
is returned. If the time is less than or
equal to zero, the method will not wait at all.
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.
timeout | the time to wait for the read lock |
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unit | the time unit of the timeout argument |
true
if the read lock was acquiredInterruptedException | if the current thread is interrupted |
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NullPointerException | if the time unit is null |
Attempts to release this lock.
If the number of readers is now zero then the lock is made available for write lock attempts.