001/**
002 * Copyright (C) 2012 FuseSource, Inc.
003 * http://fusesource.com
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *    http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.fusesource.hawtdispatch;
019
020import java.util.LinkedList;
021import java.util.concurrent.Executor;
022
023import static org.fusesource.hawtdispatch.Dispatch.*;
024
025/**
026 * Sends runnable tasks to a DispatchQueue via a an EventAggregator
027 * so that they first batch up on the sender side before being
028 * sent to the DispatchQueue which then executes that tasks.
029 *
030 * @author <a href="http://hiramchirino.com">Hiram Chirino</a>
031 */
032public class AggregatingExecutor implements Executor {
033
034    final DispatchQueue queue;
035    final CustomDispatchSource<Runnable, LinkedList<Runnable>> source;
036
037    public AggregatingExecutor(DispatchQueue queue) {
038        this.queue = queue;
039        this.source = createSource(EventAggregators.<Runnable>linkedList(), queue);
040        this.source.setEventHandler(new Task() {
041            public void run() {
042                for (Runnable runnable: source.getData() ) {
043                    try {
044                        runnable.run();
045                    } catch (Exception e) {
046                      Thread thread = Thread.currentThread();
047                      thread.getUncaughtExceptionHandler().uncaughtException(thread, e);
048                    }
049                }
050            }
051        });
052        this.source.resume();
053    }
054
055
056    public void suspend() {
057        source.suspend();
058    }
059
060    public void resume() {
061        source.resume();
062    }
063
064    public void execute(Runnable task) {
065        if (getCurrentQueue() == null) {
066            queue.execute(new TaskWrapper(task));
067        } else {
068            source.merge(task);
069        }
070    }
071
072}