| /** |
| * 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.hadoop.util.concurrent; |
| |
| import com.google.common.util.concurrent.AbstractFuture; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| /** A {@link Future} implemented using an {@link AsyncGet} object. */ |
| public class AsyncGetFuture<T, E extends Throwable> extends AbstractFuture<T> { |
| public static final Logger LOG = |
| LoggerFactory.getLogger(AsyncGetFuture.class); |
| |
| private final AtomicBoolean called = new AtomicBoolean(false); |
| private final AsyncGet<T, E> asyncGet; |
| |
| public AsyncGetFuture(AsyncGet<T, E> asyncGet) { |
| this.asyncGet = asyncGet; |
| } |
| |
| private void callAsyncGet(long timeout, TimeUnit unit) { |
| if (!isCancelled() && called.compareAndSet(false, true)) { |
| try { |
| set(asyncGet.get(timeout, unit)); |
| } catch (TimeoutException te) { |
| LOG.trace("TRACE", te); |
| called.compareAndSet(true, false); |
| } catch (Throwable e) { |
| LOG.trace("TRACE", e); |
| setException(e); |
| } |
| } |
| } |
| |
| @Override |
| public T get() throws InterruptedException, ExecutionException { |
| callAsyncGet(-1, TimeUnit.MILLISECONDS); |
| return super.get(); |
| } |
| |
| @Override |
| public T get(long timeout, TimeUnit unit) |
| throws InterruptedException, TimeoutException, ExecutionException { |
| callAsyncGet(timeout, unit); |
| return super.get(0, TimeUnit.MILLISECONDS); |
| } |
| |
| @Override |
| public boolean isDone() { |
| callAsyncGet(0, TimeUnit.MILLISECONDS); |
| return super.isDone(); |
| } |
| } |