| /** |
| * 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.tajo.util; |
| |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| |
| public class BasicFuture<T> implements Future<T> { |
| |
| private T result; |
| private Exception exception; |
| private boolean finished; |
| |
| @Override |
| public boolean cancel(boolean mayInterruptIfRunning) { |
| return false; |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| return false; |
| } |
| |
| @Override |
| public synchronized boolean isDone() { |
| return finished; |
| } |
| |
| @Override |
| public synchronized T get() throws InterruptedException, ExecutionException { |
| while (!finished) { |
| wait(); |
| } |
| if (exception != null) { |
| throw new ExecutionException(exception); |
| } |
| return result; |
| } |
| |
| @Override |
| public synchronized T get(long timeout, TimeUnit unit) |
| throws InterruptedException, ExecutionException, TimeoutException { |
| long remain = unit.toMillis(timeout); |
| long prev = System.currentTimeMillis(); |
| while (!finished && remain > 0) { |
| wait(remain); |
| long current = System.currentTimeMillis(); |
| remain -= current - prev; |
| prev = current; |
| } |
| if (!finished) { |
| throw new TimeoutException("Timed-out"); |
| } |
| if (exception != null) { |
| throw new ExecutionException(exception); |
| } |
| return result; |
| } |
| |
| public synchronized boolean done(T result) { |
| try { |
| if (finished) { |
| return false; |
| } |
| this.result = result; |
| this.finished = true; |
| return true; |
| } finally { |
| notifyAll(); |
| } |
| } |
| |
| public synchronized boolean failed(Exception ex) { |
| try { |
| if (finished) { |
| return false; |
| } |
| this.exception = ex; |
| this.finished = true; |
| return true; |
| } finally { |
| notifyAll(); |
| } |
| } |
| } |
| |