org.redisson.api

Interface RPermitExpirableSemaphore

All Superinterfaces:

RExpirable, RExpirableAsync, RObject, RObjectAsync, RPermitExpirableSemaphoreAsync

All Known Implementing Classes:

RedissonPermitExpirableSemaphore

public interface RPermitExpirableSemaphore
extends RExpirable, RPermitExpirableSemaphoreAsync

Semaphore object with lease time parameter support for each acquired permit.

Each permit identified by own id and could be released only using its id. Permit id is a 128-bits unique random identifier generated each time during acquiring.

Works in non-fair mode. Therefore order of acquiring is unpredictable.

Author:

Nikita Koksharov

Method Summary

Modifier and Type	Method and Description
String	acquire() Acquires a permit and returns its id.
String	acquire(long leaseTime, TimeUnit unit) Acquires a permit with defined leaseTime and return its id.
void	addPermits(int permits) Increases or decreases the number of available permits by defined value.
int	availablePermits() Returns amount of available permits.
void	release(String permitId) Releases a permit by its id.
String	tryAcquire() Tries to acquire currently available permit and return its id.
String	tryAcquire(long waitTime, long leaseTime, TimeUnit unit) Tries to acquire currently available permit with defined leaseTime and return its id.
String	tryAcquire(long waitTime, TimeUnit unit) Tries to acquire currently available permit and return its id.
boolean	tryRelease(String permitId) Tries to release permit by its id.
boolean	trySetPermits(int permits) Tries to set number of permits.
boolean	updateLeaseTime(String permitId, long leaseTime, TimeUnit unit) Overrides and updates lease time for defined permit id.

Methods inherited from interface org.redisson.api.RExpirable

clearExpire, expire, expireAt, expireAt, remainTimeToLive

Methods inherited from interface org.redisson.api.RObject

addListener, copy, delete, dump, getCodec, getName, isExists, migrate, move, removeListener, rename, renamenx, restore, restore, restoreAndReplace, restoreAndReplace, sizeInMemory, touch, unlink

Methods inherited from interface org.redisson.api.RPermitExpirableSemaphoreAsync

acquireAsync, acquireAsync, addPermitsAsync, availablePermitsAsync, releaseAsync, tryAcquireAsync, tryAcquireAsync, tryAcquireAsync, tryReleaseAsync, trySetPermitsAsync, updateLeaseTimeAsync

Methods inherited from interface org.redisson.api.RExpirableAsync

clearExpireAsync, expireAsync, expireAtAsync, expireAtAsync, remainTimeToLiveAsync

Methods inherited from interface org.redisson.api.RObjectAsync

addListenerAsync, copyAsync, deleteAsync, dumpAsync, isExistsAsync, migrateAsync, moveAsync, removeListenerAsync, renameAsync, renamenxAsync, restoreAndReplaceAsync, restoreAndReplaceAsync, restoreAsync, restoreAsync, sizeInMemoryAsync, touchAsync, unlinkAsync

Method Detail

acquire

String acquire()
        throws InterruptedException

Acquires a permit and returns its id. Waits if necessary until a permit became available.

Returns:

permit id

Throws:

InterruptedException - if the current thread is interrupted

acquire

String acquire(long leaseTime,
               TimeUnit unit)
        throws InterruptedException

Acquires a permit with defined leaseTime and return its id. Waits if necessary until a permit became available.

Parameters:

leaseTime - permit lease time

unit - time unit

Returns:

permit id

Throws:

InterruptedException - if the current thread is interrupted

tryAcquire

String tryAcquire()

Tries to acquire currently available permit and return its id.

Returns:

permit id if a permit was acquired and null otherwise

tryAcquire

String tryAcquire(long waitTime,
                  TimeUnit unit)
           throws InterruptedException

Tries to acquire currently available permit and return its id. Waits up to defined waitTime if necessary until a permit became available.

Parameters:

waitTime - the maximum time to wait

unit - the time unit

Returns:

permit id if a permit was acquired and null if the waiting time elapsed before a permit was acquired

Throws:

InterruptedException - if the current thread is interrupted

tryAcquire

String tryAcquire(long waitTime,
                  long leaseTime,
                  TimeUnit unit)
           throws InterruptedException

Tries to acquire currently available permit with defined leaseTime and return its id. Waits up to defined waitTime if necessary until a permit became available.

Parameters:

waitTime - the maximum time to wait

leaseTime - permit lease time, use -1 to make it permanent

unit - the time unit

Returns:

permit id if a permit was acquired and null if the waiting time elapsed before a permit was acquired

Throws:

InterruptedException - if the current thread is interrupted

tryRelease

boolean tryRelease(String permitId)

Tries to release permit by its id.

Parameters:

permitId - permit id

Returns:

true if a permit has been released and false otherwise

release

void release(String permitId)

Releases a permit by its id. Increases the number of available permits. Throws an exception if permit id doesn't exist or has already been released.

Parameters:

permitId - - permit id

availablePermits

int availablePermits()

Returns amount of available permits.

Returns:

number of permits

trySetPermits

boolean trySetPermits(int permits)

Tries to set number of permits.

Parameters:

permits - - number of permits

Returns:

true if permits has been set successfully, otherwise false.

addPermits

void addPermits(int permits)

Increases or decreases the number of available permits by defined value.

Parameters:

permits - amount of permits to add/remove

updateLeaseTime

boolean updateLeaseTime(String permitId,
                        long leaseTime,
                        TimeUnit unit)

Overrides and updates lease time for defined permit id.

Parameters:

permitId - permit id

leaseTime - permit lease time, use -1 to make it permanent

unit - the time unit

Returns:

true if permits has been updated successfully, otherwise false.