Invoke a series of runnables as closely to synchronously as possible
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* 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.
*/
import java.util.ArrayList;
import java.util.List;
import java.util.Iterator;
import java.util.Collections;
import java.util.Random;
/**
* The purpose of this class is to invoke a series of runnables as
* closely to synchronously as possible. It does this by starting
* a thread for each one, getting the threads into there run method,
* then quickly running through (in random order) and notifying each
* thread.
*/
public class ThreadPounder {
List runnables;
Object [] threads;
Object lock = new Object();
public ThreadPounder(List runnables)
throws InterruptedException {
this(runnables, new Random(1234));
}
public ThreadPounder(List runnables, Random rand)
throws InterruptedException {
this.runnables = new ArrayList(runnables);
Collections.shuffle(this.runnables, rand);
threads = new Object[this.runnables.size()];
int i=0;
Iterator iter= this.runnables.iterator();
synchronized (lock) {
while (iter.hasNext()) {
Thread t = new SyncThread((Runnable)iter.next());
t.start();
lock.wait();
threads[i] = t;
i++;
}
}
}
public void start() {
synchronized(this) {
this.notifyAll();
}
}
class SyncThread extends Thread {
Runnable toRun;
public long runTime;
public SyncThread(Runnable toRun) {
this.toRun = toRun;
}
public void run() {
try {
synchronized (ThreadPounder.this) {
synchronized (lock) {
// Let pounder know I'm ready to go
lock.notify();
}
// Wait for pounder to wake me up.
ThreadPounder.this.wait();
}
toRun.run();
} catch (InterruptedException ie) {
}
}
}
public static void main(String [] str) {
List l = new ArrayList(20);
for (int i=0; i<20; i++) {
final int x = i;
l.add(new Runnable() {
public void run() {
System.out.println("Thread " + x);
}
});
}
try {
ThreadPounder tp = new ThreadPounder(l);
System.out.println("Starting:" );
tp.start();
System.out.println("All Started:" );
} catch (InterruptedException ie) {
ie.printStackTrace();
}
}
}
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