core/api/src/main/java/org/onosproject/store/service/DistributedLock.java

/*
 * Copyright 2018-present Open Networking Foundation
 *
 * 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.onosproject.store.service;

import java.time.Duration;
import java.util.Optional;

/**
 * Asynchronous lock primitive.
 */
public interface DistributedLock extends DistributedPrimitive {
    @Override
    default Type primitiveType() {
        return Type.LOCK;
    }

    /**
     * Acquires the lock, blocking until it's available.
     *
     * @return the acquired lock version
     */
    Version lock();

    /**
     * Attempts to acquire the lock.
     *
     * @return indicates whether the lock was acquired
     */
    Optional<Version> tryLock();

    /**
     * Attempts to acquire the lock for a specified amount of time.
     *
     * @param timeout the timeout after which to give up attempting to acquire the lock
     * @return indicates whether the lock was acquired
     */
    Optional<Version> tryLock(Duration timeout);

    /**
     * Unlocks the lock.
     */
    void unlock();
}