edu.oswego.cs.dl.util.concurrent
Class ReentrantLock
java.lang.Object
|
+--edu.oswego.cs.dl.util.concurrent.ReentrantLock
- All Implemented Interfaces:
- Sync
- public class ReentrantLock
- extends Object
- implements Sync
A lock with the same semantics as builtin
Java synchronized locks: Once a thread has a lock, it
can re-obtain it any number of times without blocking.
The lock is made available to other threads when
as many releases as acquires have occurred.
[ Introduction to this package. ]
Method Summary |
void |
acquire()
Wait (possibly forever) until successful passage. |
boolean |
attempt(long msecs)
Wait at most msecs to pass; report whether passed. |
long |
holds()
Return the number of unreleased acquires performed
by the current thread. |
void |
release()
Release the lock. |
void |
release(long n)
Release the lock N times. |
ReentrantLock
public ReentrantLock()
acquire
public void acquire()
throws InterruptedException
- Description copied from interface:
Sync
- Wait (possibly forever) until successful passage.
Fail only upon interuption. Interruptions always result in
`clean' failures. On failure, you can be sure that it has not
been acquired, and that no
corresponding release should be performed. Conversely,
a normal return guarantees that the acquire was successful.
- Specified by:
acquire
in interface Sync
attempt
public boolean attempt(long msecs)
throws InterruptedException
- Description copied from interface:
Sync
- Wait at most msecs to pass; report whether passed.
The method has best-effort semantics:
The msecs bound cannot
be guaranteed to be a precise upper bound on wait time in Java.
Implementations generally can only attempt to return as soon as possible
after the specified bound. Also, timers in Java do not stop during garbage
collection, so timeouts can occur just because a GC intervened.
So, msecs arguments should be used in
a coarse-grained manner. Further,
implementations cannot always guarantee that this method
will return at all without blocking indefinitely when used in
unintended ways. For example, deadlocks may be encountered
when called in an unintended context.
- Specified by:
attempt
in interface Sync
- Following copied from interface:
edu.oswego.cs.dl.util.concurrent.Sync
- Parameters:
msecs
- the number of milleseconds to wait.
An argument less than or equal to zero means not to wait at all.
However, this may still require
access to a synchronization lock, which can impose unbounded
delay if there is a lot of contention among threads.- Returns:
- true if acquired
holds
public long holds()
- Return the number of unreleased acquires performed
by the current thread.
Returns zero if current thread does not hold lock.
release
public void release()
- Release the lock.
- Specified by:
release
in interface Sync
- Throws:
Error
- thrown if not current owner of lock
release
public void release(long n)
- Release the lock N times.
release(n)
is
equivalent in effect to:
for (int i = 0; i < n; ++i) release();
- Throws:
Error
- thrown if not current owner of lock
or has fewer than N holds on the lock
Submit a bug or feature. Check the Colt home page for the latest news.