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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC

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/**
 * Copyright (c) 2013-2024 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.time.Duration;
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
     * @return true if a permit was acquired and false
     *         otherwise
     * @throws InterruptedException if the current thread was interrupted
     */
    boolean tryAcquire(Duration waitTime) throws InterruptedException;

    /**
     * Use {@link #tryAcquire(Duration)} instead
     *
     * @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
     */
    @Deprecated
    boolean tryAcquire(long waitTime, TimeUnit unit) throws InterruptedException;

    /**
     * Use {@link #tryAcquire(int, Duration)} instead
     *
     * @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
     */
    @Deprecated
    boolean tryAcquire(int permits, 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
     * @return true if permits were acquired and false
     *         otherwise
     * @throws InterruptedException if the current thread was interrupted
     */
    boolean tryAcquire(int permits, Duration waitTime) 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);

    /**
     * Tries to set number of permits with defined time to live.
     *
     * @param timeToLive time to live
     * @param permits number of permits
     * @return true if permits has been set successfully,
     *          otherwise false if permits were already set.
     */
    boolean trySetPermits(int permits, Duration timeToLive);

    /**
     * Increases or decreases the number of available permits by defined value.
     *
     * @param permits amount of permits to add/remove
     */
    void addPermits(int permits);


}