/*
 * Copyright 2002-2019 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.integration.support.locks;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/**
 * The {@link LockRegistry} implementation which has no effect. Mainly used in cases where
 * locking itself must be conditional but an extra IF statement would clutter the code.
 * For example. In the FILE module FileWritingMessageHandler is initialized with this
 * instance of LockRegistry by default since real locking is only required if its 'append'
 * flag is set to true.
 *
 * @author Oleg Zhurakousky
 * @author Gary Russell
 * @since 2.2
 *
 */
public final class PassThruLockRegistry implements LockRegistry {

	@Override
	public Lock obtain(Object lockKey) {
		return new PassThruLock();
	}

	private static final class PassThruLock implements Lock {

		PassThruLock() {
			super();
		}

		@Override
		public void unlock() {
			// noop
		}

		@Override
		public boolean tryLock(long time, TimeUnit unit) {
			return true;
		}

		@Override
		public boolean tryLock() {
			return true;
		}

		@Override
		public Condition newCondition() {
			throw new UnsupportedOperationException("This method is not supported for this implementation of Lock");
		}

		@Override
		public void lockInterruptibly() {
			// noop
		}

		@Override
		public void lock() {
			// noop
		}
	}

}
