| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.activemq.artemis.utils; |
| |
| /** |
| * <p>This class will use the framework provided to by AbstractQueuedSynchronizer.</p> |
| * <p>AbstractQueuedSynchronizer is the framework for any sort of concurrent synchronization, such as Semaphores, events, etc, based on AtomicIntegers.</p> |
| * |
| * <p>This class works just like CountDownLatch, with the difference you can also increase the counter</p> |
| * |
| * <p>It could be used for sync points when one process is feeding the latch while another will wait when everything is done. (e.g. waiting IO completions to finish)</p> |
| * |
| * <p>On ActiveMQ Artemis we have the requirement of increment and decrement a counter until the user fires a ready event (commit). At that point we just act as a regular countDown.</p> |
| * |
| * <p>Note: This latch is reusable. Once it reaches zero, you can call up again, and reuse it on further waits.</p> |
| * |
| * <p>For example: prepareTransaction will wait for the current completions, and further adds will be called on the latch. Later on when commit is called you can reuse the same latch.</p> |
| */ |
| public class ReusableLatch extends AbstractLatch { |
| |
| public ReusableLatch() { |
| super(); |
| } |
| |
| public ReusableLatch(int count) { |
| super(count); |
| } |
| |
| @Override |
| public void countDown() { |
| control.releaseShared(1); |
| } |
| |
| @Override |
| public void countDown(final int count) { |
| control.releaseShared(count); |
| } |
| } |