LockFreeSet Example
/*
* Copyright (c) 2008 IBM Corporation
*
* Licensed 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.amino.examples;
/* The set only contains none identical items.
* This example shows the mainly interfaces of LockFreeSet.
* Including: add(), remove(), isEmpty(), size(), iterator().
*
* The SetAdder class try to add items maybe identical.
* The SetRemover will remove no more than ELEMENT_NUM items in the set.
* The main thread will wait until all the threads in the pool to finish, and it will
* print all the items still in the Set.
*
* 2009/05/22
*/
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.amino.ds.lockfree.LockFreeSet;
public class SetExample {
public static final int ELEMENT_NUM = 1000;
private static final int TASKS_NUM = 4;
public static void main(String[] argvs) {
ExecutorService exec = Executors.newFixedThreadPool(TASKS_NUM);
final LockFreeSet<String> setStr = new LockFreeSet<String>();
for (int i = 0; i < TASKS_NUM; ++i) {
exec.submit(new SetAdder(setStr));
if ( i%2 == 0)exec.submit(new SetRemover(setStr));
}
exec.shutdown();
// Wait until all the threads in pool to finish.
try {
while(!exec.awaitTermination(600, TimeUnit.SECONDS));
} catch (InterruptedException e) {
e.printStackTrace();
}
// If the Set is empty now, the program will exit.
if (setStr.isEmpty())
{
System.out.println("The Set is empty, so I will exit!");
System.exit(1);
}
// The simple way for printing all the elements in List.
for (String str : setStr)
System.out.println(str);
// Clear all the elements.
System.out.println("before clear size: " + setStr.size());
setStr.clear();
System.out.println("cleared size: " + setStr.size());
}
}
/*
* The SetAdder try to add items which maybe identical to Set.
*/
class SetAdder implements Runnable {
Set<String> tskSet;
private int count = 0;
public SetAdder(Set<String> taskSet)
{
tskSet = taskSet;
}
public void run(){
while (count < ListExample.ELEMENT_NUM)
{
//The duplicated number shouldn't be added!
if (tskSet.add(Integer.toString(count++))) {
System.out.println(Thread.currentThread()+ " Added " + count);
} else {
System.out.println(Thread.currentThread()+ " !!!try to add identical item:" + count);
}
}
Thread.yield();
}
}
// The SetRemover class will remove the items.
class SetRemover implements Runnable {
Set<String> tskSet;
private int count = 0;
public SetRemover(Set<String> taskSet)
{
tskSet = taskSet;
}
public void run(){
int times = 0;
while (times < ListExample.ELEMENT_NUM)
{
if (!tskSet.remove(Integer.toString(count++))) {
System.out.println(Thread.currentThread()+ "Removed: " + count);
}
times++;
}
Thread.yield();
}
}
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