RedissonSemaphore (Redisson 2.11.1 API)

java.lang.Object
- org.redisson.RedissonObject
- - org.redisson.RedissonSemaphore

All Implemented Interfaces:

RExpirable, RExpirableAsync, RObject, RObjectAsync, RSemaphore, RSemaphoreAsync

Direct Known Subclasses:

RedissonQueueSemaphore
```
public class RedissonSemaphore
extends RedissonObject
implements RSemaphore
```
Distributed and concurrent implementation of Semaphore.
Works in non-fair mode. Therefore order of acquiring is unpredictable.

Author:

Nikita Koksharov

Field Summary
- Fields inherited from class org.redisson.RedissonObject
  codec

Constructor Summary

Constructors
Constructor and Description

RedissonSemaphore(CommandAsyncExecutor commandExecutor, String name, SemaphorePubSub semaphorePubSub)

Constructors
Constructor and Description
`RedissonSemaphore(CommandAsyncExecutor commandExecutor, String name, SemaphorePubSub semaphorePubSub)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`acquire()` Acquires a permit from this semaphore, blocking until one is available, or the thread is interrupted.
`void`	`acquire(int permits)` Acquires the given number of permits from this semaphore, blocking until all are available, or the thread is interrupted.
`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.
`int`	`availablePermits()` Returns the current number of available permits.
`boolean`	`clearExpire()` Clear an expire timeout or expire date for object.
`RFuture<Boolean>`	`clearExpireAsync()` Clear an expire timeout or expire date for object in async mode.
`int`	`drainPermits()` Acquires and returns all permits that are immediately available.
`boolean`	`expire(long timeToLive, TimeUnit timeUnit)` Set a timeout for object.
`RFuture<Boolean>`	`expireAsync(long timeToLive, TimeUnit timeUnit)` Set a timeout for object in async mode.
`boolean`	`expireAt(Date timestamp)` Set an expire date for object.
`boolean`	`expireAt(long timestamp)` Set an expire date for object.
`RFuture<Boolean>`	`expireAtAsync(Date timestamp)` Set an expire date for object in async mode.
`RFuture<Boolean>`	`expireAtAsync(long timestamp)` Set an expire date for object in async mode.
`static String`	`getChannelName(String name)`
`void`	`reducePermits(int permits)` Shrinks the number of available permits by the indicated reduction.
`RFuture<Void>`	`reducePermitsAsync(int permits)` Shrinks the number of available permits by the indicated reduction.
`void`	`release()` Releases a permit, returning it to the semaphore.
`void`	`release(int permits)` Releases the given number of permits, returning them to the semaphore.
`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.
`long`	`remainTimeToLive()` Remaining time to live of Redisson object that has a timeout
`RFuture<Long>`	`remainTimeToLiveAsync()` Get remaining time to live of object in seconds.
`boolean`	`tryAcquire()` Acquires a permit only if one is available at the time of invocation.
`boolean`	`tryAcquire(int permits)` Acquires the given number of permits only if all are available at the time of invocation.
`boolean`	`tryAcquire(int permits, long waitTime, TimeUnit unit)` Acquires the given number of permits only if all are available within the given waiting time and the current thread has not been interrupted.
`boolean`	`tryAcquire(long time, TimeUnit unit)` Acquires a permit from this semaphore, if one becomes available within the given waiting time and the current thread has not been interrupted.
`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 value `true`, reducing the number of available permits by one.
`boolean`	`trySetPermits(int permits)` Sets number of permits.
`RFuture<Boolean>`	`trySetPermitsAsync(int permits)` Sets number of permits.

Methods inherited from class org.redisson.RedissonObject
await, delete, deleteAsync, encode, encode, encode, encodeMapKey, encodeMapKeys, encodeMapValue, encodeMapValues, get, getCodec, getName, getName, isExists, isExistsAsync, migrate, migrateAsync, move, moveAsync, prefixName, rename, renameAsync, renamenx, renamenxAsync, suffixName, touch, touchAsync, unlink, unlinkAsync

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.redisson.api.RExpirable
clearExpire, expire, expireAt, expireAt, remainTimeToLive

Methods inherited from interface org.redisson.api.RObject
delete, getCodec, getName, isExists, migrate, move, rename, renamenx, touch, unlink

Methods inherited from interface org.redisson.api.RExpirableAsync
clearExpireAsync, expireAsync, expireAtAsync, expireAtAsync, remainTimeToLiveAsync

Methods inherited from interface org.redisson.api.RObjectAsync
deleteAsync, isExistsAsync, migrateAsync, moveAsync, renameAsync, renamenxAsync, touchAsync, unlinkAsync

- Constructor Detail
  - RedissonSemaphore
```
public RedissonSemaphore(CommandAsyncExecutor commandExecutor,
                         String name,
                         SemaphorePubSub semaphorePubSub)
```
- Method Detail
  - getChannelName
```
public static String getChannelName(String name)
```
  - acquire
```
public void acquire()
             throws InterruptedException
```
    Description copied from interface: RSemaphore
    Acquires a permit from this semaphore, blocking until one is available, or the thread is interrupted.
    Acquires a permit, if one is available and returns immediately, reducing the number of available permits by one.
    If no permit is available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:
    - Some other thread invokes the RSemaphore.release() method for this semaphore and the current thread is next to be assigned a permit; or
    - Some other thread interrupts the current thread.
    Specified by:
    
    acquire in interface RSemaphore
    
    Throws:
    
    InterruptedException - if the current thread is interrupted
  - acquire
```
public void acquire(int permits)
             throws InterruptedException
```
    Description copied from interface: RSemaphore
    Acquires the given number of permits from this semaphore, blocking until all are available, or the thread is interrupted.
    Acquires the given number of permits, if they are available, and returns immediately, reducing the number of available permits by the given amount.
    If insufficient permits are available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happens:
    - Some other thread invokes one of the release methods for this semaphore, the current thread is next to be assigned permits and the number of available permits satisfies this request; or
    - Some other thread interrupts the current thread.
    Specified by:
    
    acquire in interface RSemaphore
    
    Parameters:
    
    permits - the number of permits to acquire
    
    Throws:
    
    InterruptedException - if the current thread is interrupted
  - acquireAsync
```
public RFuture<Void> acquireAsync()
```
    Description copied from interface: RSemaphoreAsync
    
    Acquires a permit from this semaphore.
    Acquires a permit, if one is available and returns immediately, reducing the number of available permits by one.
    
    Specified by:
    
    acquireAsync in interface RSemaphoreAsync
    
    Returns:
    
    void
  - acquireAsync
```
public RFuture<Void> acquireAsync(int permits)
```
    Description copied from interface: RSemaphoreAsync
    
    Acquires the given number of permits, if they are available, and returns immediately, reducing the number of available permits by the given amount.
    
    Specified by:
    
    acquireAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - the number of permits to acquire
    
    Returns:
    
    void
  - tryAcquire
```
public boolean tryAcquire()
```
    Description copied from interface: RSemaphore
    
    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.
    
    Specified by:
    
    tryAcquire in interface RSemaphore
    
    Returns:
    
    true if a permit was acquired and false otherwise
  - tryAcquire
```
public boolean tryAcquire(int permits)
```
    Description copied from interface: RSemaphore
    
    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 permits.
    If no permits are available then this method will return immediately with the value false.
    
    Specified by:
    
    tryAcquire in interface RSemaphore
    
    Parameters:
    
    permits - the number of permits to acquire
    
    Returns:
    
    true if a permit was acquired and false otherwise
  - tryAcquireAsync
```
public RFuture<Boolean> tryAcquireAsync()
```
    Description copied from interface: RSemaphoreAsync
    
    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.
    
    Specified by:
    
    tryAcquireAsync in interface RSemaphoreAsync
    
    Returns:
    
    true if a permit was acquired and false otherwise
  - tryAcquireAsync
```
public RFuture<Boolean> tryAcquireAsync(int permits)
```
    Description copied from interface: RSemaphoreAsync
    
    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.
    
    Specified by:
    
    tryAcquireAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - the number of permits to acquire
    
    Returns:
    
    true if a permit was acquired and false otherwise
  - tryAcquireAsync
```
public RFuture<Boolean> tryAcquireAsync(long waitTime,
                                        TimeUnit unit)
```
    Description copied from interface: RSemaphoreAsync
    
    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.
    
    Specified by:
    
    tryAcquireAsync in interface RSemaphoreAsync
    
    Parameters:
    
    waitTime - the maximum time to wait for a permit
    
    unit - the time unit of the timeout argument
    
    Returns:
    
    true if a permit was acquired and false if the waiting time elapsed before a permit was acquired
  - tryAcquire
```
public boolean tryAcquire(int permits,
                          long waitTime,
                          TimeUnit unit)
                   throws InterruptedException
```
    Description copied from interface: RSemaphore
    Acquires the given number of permits only if all are available within the given waiting time and the current thread has not been interrupted.
    Acquires a permits, if all are available and returns immediately, with the value true, reducing the number of available permits by one.
    If no permit is available then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:
    - Some other thread invokes the RSemaphore.release() method for this semaphore and the current thread is next to be assigned a permit; or
    - Some other thread interrupts the current thread; or
    - The specified waiting time elapses.
    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.
    Specified by:
    
    tryAcquire in interface RSemaphore
    
    Parameters:
    
    permits - amount
    
    waitTime - the maximum time to wait for a permit
    
    unit - the time unit of the timeout argument
    
    Returns:
    
    true if a permit was acquired and false if the waiting time elapsed before a permit was acquired
    
    Throws:
    
    InterruptedException - if the current thread is interrupted
  - tryAcquireAsync
```
public RFuture<Boolean> tryAcquireAsync(int permits,
                                        long waitTime,
                                        TimeUnit unit)
```
    Description copied from interface: RSemaphoreAsync
    
    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.
    
    Specified by:
    
    tryAcquireAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - amount
    
    waitTime - the maximum time to wait for a available permits
    
    unit - the time unit of the timeout argument
    
    Returns:
    
    true if a permit was acquired and false if the waiting time elapsed before a permit was acquired
  - tryAcquire
```
public boolean tryAcquire(long time,
                          TimeUnit unit)
                   throws InterruptedException
```
    Description copied from interface: RSemaphore
    Acquires a permit from this semaphore, if one becomes available within the given waiting time and the current thread has not been interrupted.
    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 the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happens:
    - Some other thread invokes the RSemaphore.release() method for this semaphore and the current thread is next to be assigned a permit; or
    - Some other thread interrupts the current thread; or
    - The specified waiting time elapses.
    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.
    Specified by:
    
    tryAcquire in interface RSemaphore
    
    Parameters:
    
    time - the maximum time to wait for a permit
    
    unit - the time unit of the timeout argument
    
    Returns:
    
    true if a permit was acquired and false if the waiting time elapsed before a permit was acquired
    
    Throws:
    
    InterruptedException - if the current thread is interrupted
  - release
```
public void release()
```
    Description copied from interface: RSemaphore
    
    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 RSemaphore.acquire(). Correct usage of a semaphore is established by programming convention in the application.
    
    Specified by:
    
    release in interface RSemaphore
  - release
```
public void release(int permits)
```
    Description copied from interface: RSemaphore
    
    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 RSemaphore.acquire(). Correct usage of a semaphore is established by programming convention in the application.
    
    Specified by:
    
    release in interface RSemaphore
    
    Parameters:
    
    permits - amount
  - releaseAsync
```
public RFuture<Void> releaseAsync()
```
    Description copied from interface: RSemaphoreAsync
    
    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 RSemaphoreAsync.acquireAsync(). Correct usage of a semaphore is established by programming convention in the application.
    
    Specified by:
    
    releaseAsync in interface RSemaphoreAsync
    
    Returns:
    
    void
  - releaseAsync
```
public RFuture<Void> releaseAsync(int permits)
```
    Description copied from interface: RSemaphoreAsync
    
    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 RSemaphoreAsync.acquireAsync(). Correct usage of a semaphore is established by programming convention in the application.
    
    Specified by:
    
    releaseAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - amount
    
    Returns:
    
    void
  - drainPermits
```
public int drainPermits()
```
    Description copied from interface: RSemaphore
    
    Acquires and returns all permits that are immediately available.
    
    Specified by:
    
    drainPermits in interface RSemaphore
    
    Returns:
    
    the number of permits acquired
  - availablePermits
```
public int availablePermits()
```
    Description copied from interface: RSemaphore
    
    Returns the current number of available permits.
    
    Specified by:
    
    availablePermits in interface RSemaphore
    
    Returns:
    
    number of available permits
  - trySetPermits
```
public boolean trySetPermits(int permits)
```
    Description copied from interface: RSemaphore
    
    Sets number of permits.
    
    Specified by:
    
    trySetPermits in interface RSemaphore
    
    Parameters:
    
    permits - - number of permits
    
    Returns:
    
    true if permits has been set successfully, otherwise false.
  - trySetPermitsAsync
```
public RFuture<Boolean> trySetPermitsAsync(int permits)
```
    Description copied from interface: RSemaphoreAsync
    
    Sets number of permits.
    
    Specified by:
    
    trySetPermitsAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - - number of permits
    
    Returns:
    
    true if permits has been set successfully, otherwise false.
  - reducePermits
```
public void reducePermits(int permits)
```
    Description copied from interface: RSemaphore
    
    Shrinks the number of available permits by the indicated reduction.
    
    Specified by:
    
    reducePermits in interface RSemaphore
    
    Parameters:
    
    permits - - reduction the number of permits to remove
  - reducePermitsAsync
```
public RFuture<Void> reducePermitsAsync(int permits)
```
    Description copied from interface: RSemaphoreAsync
    
    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 from RSemaphoreAsync.acquireAsync() in that it does not block waiting for permits to become available.
    
    Specified by:
    
    reducePermitsAsync in interface RSemaphoreAsync
    
    Parameters:
    
    permits - - reduction the number of permits to remove
    
    Returns:
    
    void
  - expire
```
public boolean expire(long timeToLive,
                      TimeUnit timeUnit)
```
    Description copied from interface: RExpirable
    
    Set a timeout for object. After the timeout has expired, the key will automatically be deleted.
    
    Specified by:
    
    expire in interface RExpirable
    
    Parameters:
    
    timeToLive - - timeout before object will be deleted
    
    timeUnit - - timeout time unit
    
    Returns:
    
    true if the timeout was set and false if not
  - expireAsync
```
public RFuture<Boolean> expireAsync(long timeToLive,
                                    TimeUnit timeUnit)
```
    Description copied from interface: RExpirableAsync
    
    Set a timeout for object in async mode. After the timeout has expired, the key will automatically be deleted.
    
    Specified by:
    
    expireAsync in interface RExpirableAsync
    
    Parameters:
    
    timeToLive - - timeout before object will be deleted
    
    timeUnit - - timeout time unit
    
    Returns:
    
    true if the timeout was set and false if not
  - expireAt
```
public boolean expireAt(long timestamp)
```
    Description copied from interface: RExpirable
    
    Set an expire date for object. When expire date comes the key will automatically be deleted.
    
    Specified by:
    
    expireAt in interface RExpirable
    
    Parameters:
    
    timestamp - - expire date in milliseconds (Unix timestamp)
    
    Returns:
    
    true if the timeout was set and false if not
  - expireAtAsync
```
public RFuture<Boolean> expireAtAsync(long timestamp)
```
    Description copied from interface: RExpirableAsync
    
    Set an expire date for object in async mode. When expire date comes the key will automatically be deleted.
    
    Specified by:
    
    expireAtAsync in interface RExpirableAsync
    
    Parameters:
    
    timestamp - - expire date in seconds (Unix timestamp)
    
    Returns:
    
    true if the timeout was set and false if not
  - expireAt
```
public boolean expireAt(Date timestamp)
```
    Description copied from interface: RExpirable
    
    Set an expire date for object. When expire date comes the key will automatically be deleted.
    
    Specified by:
    
    expireAt in interface RExpirable
    
    Parameters:
    
    timestamp - - expire date
    
    Returns:
    
    true if the timeout was set and false if not
  - expireAtAsync
```
public RFuture<Boolean> expireAtAsync(Date timestamp)
```
    Description copied from interface: RExpirableAsync
    
    Set an expire date for object in async mode. When expire date comes the key will automatically be deleted.
    
    Specified by:
    
    expireAtAsync in interface RExpirableAsync
    
    Parameters:
    
    timestamp - - expire date
    
    Returns:
    
    true if the timeout was set and false if not
  - clearExpire
```
public boolean clearExpire()
```
    Description copied from interface: RExpirable
    
    Clear an expire timeout or expire date for object.
    
    Specified by:
    
    clearExpire in interface RExpirable
    
    Returns:
    
    true if timeout was removed false if object does not exist or does not have an associated timeout
  - clearExpireAsync
```
public RFuture<Boolean> clearExpireAsync()
```
    Description copied from interface: RExpirableAsync
    
    Clear an expire timeout or expire date for object in async mode. Object will not be deleted.
    
    Specified by:
    
    clearExpireAsync in interface RExpirableAsync
    
    Returns:
    
    true if the timeout was cleared and false if not
  - remainTimeToLive
```
public long remainTimeToLive()
```
    Description copied from interface: RExpirable
    
    Remaining time to live of Redisson object that has a timeout
    
    Specified by:
    
    remainTimeToLive in interface RExpirable
    
    Returns:
    
    time in milliseconds -2 if the key does not exist. -1 if the key exists but has no associated expire.
  - remainTimeToLiveAsync
```
public RFuture<Long> remainTimeToLiveAsync()
```
    Description copied from interface: RExpirableAsync
    
    Get remaining time to live of object in seconds.
    
    Specified by:
    
    remainTimeToLiveAsync in interface RExpirableAsync
    
    Returns:
    
    -1 if object does not exist or time in seconds

Class RedissonSemaphore

Field Summary

Fields inherited from class org.redisson.RedissonObject

Constructor Summary

Method Summary

Methods inherited from class org.redisson.RedissonObject

Methods inherited from class java.lang.Object

Methods inherited from interface org.redisson.api.RExpirable

Methods inherited from interface org.redisson.api.RObject

Methods inherited from interface org.redisson.api.RExpirableAsync

Methods inherited from interface org.redisson.api.RObjectAsync

Constructor Detail

RedissonSemaphore

Method Detail

getChannelName

acquire

acquire

acquireAsync

acquireAsync

tryAcquire

tryAcquire

tryAcquireAsync

tryAcquireAsync

tryAcquireAsync

tryAcquire

tryAcquireAsync

tryAcquire

release

release

releaseAsync

releaseAsync

drainPermits

availablePermits

trySetPermits

trySetPermitsAsync

reducePermits

reducePermitsAsync

expire

expireAsync

expireAt

expireAtAsync

expireAt

expireAtAsync

clearExpire

clearExpireAsync

remainTimeToLive

remainTimeToLiveAsync