| /* |
| * 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.cassandra.distributed.util; |
| |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| |
| import com.google.common.util.concurrent.UncheckedTimeoutException; |
| |
| import org.apache.cassandra.utils.Shared; |
| import org.apache.cassandra.utils.concurrent.UncheckedInterruptedException; |
| |
| @Shared |
| public class TwoWay implements AutoCloseable |
| { |
| private volatile CountDownLatch first = new CountDownLatch(1); |
| private final CountDownLatch second = new CountDownLatch(1); |
| |
| public void awaitAndEnter() |
| { |
| await(); |
| enter(); |
| } |
| |
| public void await() |
| { |
| await(first); |
| first = null; |
| } |
| |
| public void enter() |
| { |
| if (first != null) |
| { |
| first.countDown(); |
| await(second); |
| } |
| else |
| { |
| second.countDown(); |
| } |
| } |
| |
| private void await(CountDownLatch latch) |
| { |
| try |
| { |
| if (!latch.await(1, TimeUnit.MINUTES)) |
| throw new UncheckedTimeoutException("Timeout waiting on " + (latch == second ? "second" : "first") + " latch"); |
| } |
| catch (InterruptedException e) |
| { |
| throw new UncheckedInterruptedException(e); |
| } |
| } |
| |
| @Override |
| public void close() |
| { |
| if (first != null) |
| first.countDown(); |
| first = null; |
| second.countDown(); |
| } |
| } |