Interface RSemaphoreAsync
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- All Superinterfaces:
RExpirableAsync
,RObjectAsync
- All Known Subinterfaces:
RSemaphore
- All Known Implementing Classes:
RedissonQueueSemaphore
,RedissonSemaphore
public interface RSemaphoreAsync extends RExpirableAsync
Distributed and concurrent implementation ofSemaphore
.Works in non-fair mode. Therefore order of acquiring is unpredictable.
- Author:
- Nikita Koksharov
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description RFuture<Void>
acquireAsync()
Acquires a permit from this semaphore.RFuture<Void>
acquireAsync(int permits)
Acquires the given number of permits, if they are available, and returns immediately, reducing the number of available permits by the given amount.RFuture<Void>
reducePermitsAsync(int permits)
Shrinks the number of available permits by the indicated reduction.RFuture<Void>
releaseAsync()
Releases a permit, returning it to the semaphore.RFuture<Void>
releaseAsync(int permits)
Releases the given number of permits, returning them to the semaphore.RFuture<Boolean>
tryAcquireAsync()
Acquires a permit only if one is available at the time of invocation.RFuture<Boolean>
tryAcquireAsync(int permits)
Acquires the given number of permits only if all are available at the time of invocation.RFuture<Boolean>
tryAcquireAsync(int permits, long waitTime, TimeUnit unit)
Acquires the given number of permits only if all are available within the given waiting time.RFuture<Boolean>
tryAcquireAsync(long waitTime, TimeUnit unit)
Acquires a permit, if one is available and returns immediately, with the valuetrue
, reducing the number of available permits by one.RFuture<Boolean>
trySetPermitsAsync(int permits)
Sets number of permits.-
Methods inherited from interface org.redisson.api.RExpirableAsync
clearExpireAsync, expireAsync, expireAtAsync, expireAtAsync, remainTimeToLiveAsync
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Methods inherited from interface org.redisson.api.RObjectAsync
copyAsync, deleteAsync, dumpAsync, isExistsAsync, migrateAsync, moveAsync, renameAsync, renamenxAsync, restoreAndReplaceAsync, restoreAndReplaceAsync, restoreAsync, restoreAsync, touchAsync, unlinkAsync
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Method Detail
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tryAcquireAsync
RFuture<Boolean> tryAcquireAsync()
Acquires a permit only if one is available at the time of invocation.Acquires a permit, if one is available and returns immediately, with the value
true
, reducing the number of available permits by one.If no permit is available then this method will return immediately with the value
false
.- Returns:
true
if a permit was acquired andfalse
otherwise
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tryAcquireAsync
RFuture<Boolean> tryAcquireAsync(int permits)
Acquires the given number of permits only if all are available at the time of invocation.Acquires a permits, if all are available and returns immediately, with the value
true
, reducing the number of available permits by given number of permitss.If no permits are available then this method will return immediately with the value
false
.- Parameters:
permits
- the number of permits to acquire- Returns:
true
if a permit was acquired andfalse
otherwise
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acquireAsync
RFuture<Void> acquireAsync()
Acquires a permit from this semaphore.Acquires a permit, if one is available and returns immediately, reducing the number of available permits by one.
- Returns:
- void
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acquireAsync
RFuture<Void> acquireAsync(int permits)
Acquires the given number of permits, if they are available, and returns immediately, reducing the number of available permits by the given amount.- Parameters:
permits
- the number of permits to acquire- Returns:
- void
- Throws:
IllegalArgumentException
- ifpermits
is negative
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releaseAsync
RFuture<Void> releaseAsync()
Releases a permit, returning it to the semaphore.Releases a permit, increasing the number of available permits by one. If any threads of Redisson client are trying to acquire a permit, then one is selected and given the permit that was just released.
There is no requirement that a thread that releases a permit must have acquired that permit by calling
acquireAsync()
. Correct usage of a semaphore is established by programming convention in the application.- Returns:
- void
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releaseAsync
RFuture<Void> releaseAsync(int permits)
Releases the given number of permits, returning them to the semaphore.Releases the given number of permits, increasing the number of available permits by the given number of permits. If any threads of Redisson client are trying to acquire a permits, then next threads is selected and tries to acquire the permits that was just released.
There is no requirement that a thread that releases a permits must have acquired that permit by calling
acquireAsync()
. Correct usage of a semaphore is established by programming convention in the application.- Parameters:
permits
- amount- Returns:
- void
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trySetPermitsAsync
RFuture<Boolean> trySetPermitsAsync(int permits)
Sets number of permits.- Parameters:
permits
- - number of permits- Returns:
true
if permits has been set successfully, otherwisefalse
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tryAcquireAsync
RFuture<Boolean> tryAcquireAsync(long waitTime, TimeUnit unit)
Acquires a permit, if one is available and returns immediately, with the value
true
, reducing the number of available permits by one.If a permit is acquired then the value
true
is returned.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.- Parameters:
waitTime
- the maximum time to wait for a permitunit
- the time unit of thetimeout
argument- Returns:
true
if a permit was acquired andfalse
if the waiting time elapsed before a permit was acquired
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tryAcquireAsync
RFuture<Boolean> tryAcquireAsync(int permits, long waitTime, TimeUnit unit)
Acquires the given number of permits only if all are available within the given waiting time.Acquires a permits, if all are available and returns immediately, with the value
true
, reducing the number of available permits by one.If a permits is acquired then the value
true
is returned.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.- Parameters:
permits
- amountwaitTime
- the maximum time to wait for a available permitsunit
- the time unit of thetimeout
argument- Returns:
true
if a permit was acquired andfalse
if the waiting time elapsed before a permit was acquired
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reducePermitsAsync
RFuture<Void> reducePermitsAsync(int permits)
Shrinks the number of available permits by the indicated reduction. This method can be useful in subclasses that use semaphores to track resources that become unavailable. This method differs fromacquireAsync()
in that it does not block waiting for permits to become available.- Parameters:
permits
- - reduction the number of permits to remove- Returns:
- void
- Throws:
IllegalArgumentException
- ifreduction
is negative
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