Package EDU.oswego.cs.dl.util.concurrent
Class PrioritySemaphore
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- EDU.oswego.cs.dl.util.concurrent.Semaphore
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- EDU.oswego.cs.dl.util.concurrent.QueuedSemaphore
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- EDU.oswego.cs.dl.util.concurrent.PrioritySemaphore
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- All Implemented Interfaces:
Sync
public class PrioritySemaphore extends QueuedSemaphore
A Semaphore that grants requests to threads with higher Thread priority rather than lower priority when there is contention. Ordering of requests with the same priority is approximately FIFO. Priorities are based on Thread.getPriority. Changing the priority of an already-waiting thread does NOT change its ordering. This class also does not specially deal with priority inversion -- when a new high-priority thread enters while a low-priority thread is currently running, their priorities are not artificially manipulated.
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected static class
PrioritySemaphore.PriorityWaitQueue
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Nested classes/interfaces inherited from class EDU.oswego.cs.dl.util.concurrent.QueuedSemaphore
QueuedSemaphore.WaitQueue
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Field Summary
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Fields inherited from class EDU.oswego.cs.dl.util.concurrent.QueuedSemaphore
wq_
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Fields inherited from interface EDU.oswego.cs.dl.util.concurrent.Sync
ONE_CENTURY, ONE_DAY, ONE_HOUR, ONE_MINUTE, ONE_SECOND, ONE_WEEK, ONE_YEAR
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Constructor Summary
Constructors Constructor Description PrioritySemaphore(long initialPermits)
Create a Semaphore with the given initial number of permits.
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Method Summary
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Methods inherited from class EDU.oswego.cs.dl.util.concurrent.QueuedSemaphore
acquire, attempt, getSignallee, precheck, recheck, release, release
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Constructor Detail
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PrioritySemaphore
public PrioritySemaphore(long initialPermits)
Create a Semaphore with the given initial number of permits. Using a seed of one makes the semaphore act as a mutual exclusion lock. Negative seeds are also allowed, in which case no acquires will proceed until the number of releases has pushed the number of permits past 0.
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