| /* |
| * ==================================================================== |
| * 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. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| */ |
| package org.apache.hc.core5.concurrent; |
| |
| import java.util.concurrent.CancellationException; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| |
| import org.apache.hc.core5.util.Args; |
| import org.apache.hc.core5.util.TimeoutValueException; |
| |
| /** |
| * Basic implementation of the {@link Future} interface. {@code BasicFuture} |
| * can be put into a completed state by invoking any of the following methods: |
| * {@link #cancel()}, {@link #failed(Exception)}, or {@link #completed(Object)}. |
| * |
| * @param <T> the future result type of an asynchronous operation. |
| * @since 4.2 |
| */ |
| public class BasicFuture<T> implements Future<T>, Cancellable { |
| |
| private final FutureCallback<T> callback; |
| |
| private volatile boolean completed; |
| private volatile boolean cancelled; |
| private volatile T result; |
| private volatile Exception ex; |
| |
| public BasicFuture(final FutureCallback<T> callback) { |
| super(); |
| this.callback = callback; |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| return this.cancelled; |
| } |
| |
| @Override |
| public boolean isDone() { |
| return this.completed; |
| } |
| |
| private T getResult() throws ExecutionException { |
| if (this.ex != null) { |
| throw new ExecutionException(this.ex); |
| } |
| if (cancelled) { |
| throw new CancellationException(); |
| } |
| return this.result; |
| } |
| |
| @Override |
| public synchronized T get() throws InterruptedException, ExecutionException { |
| while (!this.completed) { |
| wait(); |
| } |
| return getResult(); |
| } |
| |
| @Override |
| public synchronized T get(final long timeout, final TimeUnit unit) |
| throws InterruptedException, ExecutionException, TimeoutException { |
| Args.notNull(unit, "Time unit"); |
| final long msecs = unit.toMillis(timeout); |
| final long startTime = (msecs <= 0) ? 0 : System.currentTimeMillis(); |
| long waitTime = msecs; |
| if (this.completed) { |
| return getResult(); |
| } else if (waitTime <= 0) { |
| throw TimeoutValueException.fromMilliseconds(msecs, msecs + Math.abs(waitTime)); |
| } else { |
| for (;;) { |
| wait(waitTime); |
| if (this.completed) { |
| return getResult(); |
| } |
| waitTime = msecs - (System.currentTimeMillis() - startTime); |
| if (waitTime <= 0) { |
| throw TimeoutValueException.fromMilliseconds(msecs, msecs + Math.abs(waitTime)); |
| } |
| } |
| } |
| } |
| |
| public boolean completed(final T result) { |
| synchronized(this) { |
| if (this.completed) { |
| return false; |
| } |
| this.completed = true; |
| this.result = result; |
| notifyAll(); |
| } |
| if (this.callback != null) { |
| this.callback.completed(result); |
| } |
| return true; |
| } |
| |
| public boolean failed(final Exception exception) { |
| synchronized(this) { |
| if (this.completed) { |
| return false; |
| } |
| this.completed = true; |
| this.ex = exception; |
| notifyAll(); |
| } |
| if (this.callback != null) { |
| this.callback.failed(exception); |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean cancel(final boolean mayInterruptIfRunning) { |
| synchronized(this) { |
| if (this.completed) { |
| return false; |
| } |
| this.completed = true; |
| this.cancelled = true; |
| notifyAll(); |
| } |
| if (this.callback != null) { |
| this.callback.cancelled(); |
| } |
| return true; |
| } |
| |
| @Override |
| public boolean cancel() { |
| return cancel(true); |
| } |
| |
| } |