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/**
* Copyright (c) 2013-2021 Nikita Koksharov
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.redisson.api;
import java.util.concurrent.TimeUnit;
/**
* Redis based implementation of {@link java.util.concurrent.Semaphore}.
*
* Works in non-fair mode. Therefore order of acquiring is unpredictable.
*
* @author Nikita Koksharov
*
*/
public interface RSemaphore extends RExpirable, RSemaphoreAsync {
/**
* Acquires a permit.
* Waits if necessary until a permit became available.
*
* @throws InterruptedException if the current thread was interrupted
*/
void acquire() throws InterruptedException;
/**
* Acquires defined amount of permits.
* Waits if necessary until all permits became available.
*
* @param permits the number of permits to acquire
* @throws InterruptedException if the current thread is interrupted
* @throws IllegalArgumentException if permits is negative
*/
void acquire(int permits) throws InterruptedException;
/**
* Tries to acquire currently available permit.
*
* @return true if a permit was acquired and false
* otherwise
*/
boolean tryAcquire();
/**
* Tries to acquire defined amount of currently available permits.
*
* @param permits the number of permits to acquire
* @return true if permits were acquired and false
* otherwise
*/
boolean tryAcquire(int permits);
/**
* Tries to acquire currently available permit.
* Waits up to defined waitTime if necessary until a permit became available.
*
* @param waitTime the maximum time to wait
* @param unit the time unit
* @return true if a permit was acquired and false
* otherwise
* @throws InterruptedException if the current thread was interrupted
*/
boolean tryAcquire(long waitTime, TimeUnit unit) throws InterruptedException;
/**
* Tries to acquire defined amount of currently available permits.
* Waits up to defined waitTime if necessary until all permits became available.
*
* @param permits amount of permits
* @param waitTime the maximum time to wait
* @param unit the time unit
* @return true if permits were acquired and false
* otherwise
* @throws InterruptedException if the current thread was interrupted
*/
boolean tryAcquire(int permits, long waitTime, TimeUnit unit) throws InterruptedException;
/**
* Releases a permit. Increases the number of available permits.
*
*/
void release();
/**
* Releases defined amount of permits.
* Increases the number of available permits by permits amount.
*
* @param permits amount of permits
*/
void release(int permits);
/**
* Returns amount of available permits.
*
* @return number of permits
*/
int availablePermits();
/**
* Acquires and returns all permits that are immediately available.
*
* @return number of permits
*/
int drainPermits();
/**
* Tries to set number of permits.
*
* @param permits - number of permits
* @return true if permits has been set successfully,
* otherwise false if permits were already set.
*/
boolean trySetPermits(int permits);
/**
* Increases or decreases the number of available permits by defined value.
*
* @param permits amount of permits to add/remove
*/
void addPermits(int permits);
}