import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.logging.*;
public class TimingThreadPool extends ThreadPoolExecutor {
public TimingThreadPool() {
super(1, 1, 0L, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(5));
log.addHandler(new ConsoleHandler());
}
public static void main(String...args) {
ExecutorService exec = new TimingThreadPool();
exec.submit(() -> System.out.println("a"));
exec.submit(() -> System.out.println("b"));
exec.submit(() -> System.out.println("c"));
exec.submit(() -> System.out.println("d"));
exec.shutdown();
}
private final ThreadLocal<Long> startTime = new ThreadLocal<Long>();
private final Logger log = Logger.getLogger("TimingThreadPool");
private final AtomicLong numTasks = new AtomicLong();
private final AtomicLong totalTime = new AtomicLong();
protected void beforeExecute(Thread t, Runnable r) {
super.beforeExecute(t, r);
log.fine(String.format("Thread %s: start %s", t, r));
startTime.set(System.nanoTime());
}
protected void afterExecute(Runnable r, Throwable t) {
try {
long endTime = System.nanoTime();
long taskTime = endTime - startTime.get();
numTasks.incrementAndGet();
totalTime.addAndGet(taskTime);
log.fine(String.format("Thread %s: end %s, time=%dns",
t, r, taskTime));
} finally {
super.afterExecute(r, t);
}
}
protected void terminated() {
try {
log.info(String.format("Terminated: avg time=%dns",
totalTime.get() / numTasks.get()));
} finally {
super.terminated();
}
}
}
TimingThreadPool extends ThreadPoolExecutor, added logging to collect information about thread lifecycle.
