Thread Pools 2 : Thread Pool « Threads « Java
Thread Pools 2
/*
Java Threads, 3rd Edition
By Scott Oaks, Henry Wong
3rd Edition September 2004
ISBN: 0-596-00782-5
*/
import java.util.concurrent.*;
import java.util.*;
import java.text.*;
import java.io.*;
public class SingleThreadTest {
public static void main(String[] args) {
int nTasks = 5;
int fib = 4;
SingleThreadAccess sta = new SingleThreadAccess();
for (int i = 0; i < nTasks; i++)
sta.invokeLater(new Task(fib, "Task " + i));
sta.shutdown();
}
}
class SingleThreadAccess {
private ThreadPoolExecutor tpe;
public SingleThreadAccess() {
tpe = new ThreadPoolExecutor(
1, 1, 50000L, TimeUnit.SECONDS,
new LinkedBlockingQueue<Runnable>());
} public void invokeLater(Runnable r) {
tpe.execute(r);
}
public void invokeAneWait(Runnable r) throws InterruptedException,
ExecutionException {
FutureTask task = new FutureTask(r, null);
tpe.execute(task);
task.get();
}
public void shutdown() {
tpe.shutdown();
}
}
class Task implements Runnable {
long n;
String id;
private long fib(long n) {
if (n == 0)
return 0L;
if (n == 1)
return 1L;
return fib(n - 1) + fib(n - 2);
}
public Task(long n, String id) {
this.n = n;
this.id = id;
}
public void run() {
Date d = new Date();
DateFormat df = new SimpleDateFormat("HH:mm:ss:SSS");
long startTime = System.currentTimeMillis();
d.setTime(startTime);
System.out.println("Starting task " + id + " at " + df.format(d));
fib(n);
long endTime = System.currentTimeMillis();
d.setTime(endTime);
System.out.println("Ending task " + id + " at " + df.format(d)
+ " after " + (endTime - startTime) + " milliseconds");
}
}
