| /* |
| * 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.openejb.util; |
| |
| import java.util.concurrent.locks.AbstractQueuedSynchronizer; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * @version $Rev$ $Date$ |
| */ |
| public class CountingLatch { |
| |
| private final Sync sync; |
| |
| public CountingLatch() { |
| this(0); |
| } |
| |
| public CountingLatch(int count) { |
| this.sync = new Sync(count); |
| } |
| |
| public void await() throws InterruptedException { |
| sync.acquireSharedInterruptibly(1); |
| } |
| |
| public boolean await(long timeout, TimeUnit unit) throws InterruptedException { |
| return sync.tryAcquireSharedNanos(1, unit.toNanos(timeout)); |
| } |
| |
| public void countDown() { |
| sync.releaseShared(-1); |
| } |
| |
| public void countUp() { |
| sync.releaseShared(1); |
| } |
| |
| public long getCount() { |
| return sync.getCount(); |
| } |
| |
| private static final class Sync extends AbstractQueuedSynchronizer { |
| private Sync(int count) { |
| setState(count); |
| } |
| |
| public boolean tryReleaseShared(int releases) { |
| while (true) { |
| int count = getState(); |
| |
| int next = count + releases; |
| |
| if (next < 0) return false; |
| |
| if (compareAndSetState(count, next)) { |
| return next == 0; |
| } |
| } |
| } |
| |
| public int tryAcquireShared(int acquires) { |
| return getState() == 0 ? 1: -1; |
| } |
| |
| int getCount() { |
| return getState(); |
| } |
| } |
| } |