OnJava8-Examples/concurrency/ExchangerDemo.java
Bruce Eckel 88dbdbbbcb update
2015-05-18 23:05:30 -07:00

79 lines
2.2 KiB
Java

//: concurrency/ExchangerDemo.java
import java.util.concurrent.*;
import net.mindview.util.*;
import java.util.*;
class ExchangerProducer<T> implements Runnable {
private Generator<T> generator;
private Exchanger<List<T>> exchanger;
private List<T> holder;
ExchangerProducer(Exchanger<List<T>> exchg,
Generator<T> gen, List<T> holder) {
exchanger = exchg;
generator = gen;
this.holder = holder;
}
@Override
public void run() {
try {
while(!Thread.interrupted()) {
for(int i = 0; i < ExchangerDemo.size; i++)
holder.add(generator.next());
// Exchange full for empty:
holder = exchanger.exchange(holder);
}
} catch(InterruptedException e) {
// OK to terminate this way.
}
}
}
class ExchangerConsumer<T> implements Runnable {
private Exchanger<List<T>> exchanger;
private List<T> holder;
private volatile T value;
ExchangerConsumer(Exchanger<List<T>> ex, List<T> holder){
exchanger = ex;
this.holder = holder;
}
@Override
public void run() {
try {
while(!Thread.interrupted()) {
holder = exchanger.exchange(holder);
for(T x : holder) {
value = x; // Fetch out value
holder.remove(x); // OK for CopyOnWriteArrayList
}
}
} catch(InterruptedException e) {
// OK to terminate this way.
}
System.out.println("Final value: " + value);
}
}
public class ExchangerDemo {
static int size = 10;
static int delay = 5; // Seconds
public static void main(String[] args) throws Exception {
if(args.length > 0)
size = new Integer(args[0]);
if(args.length > 1)
delay = new Integer(args[1]);
ExecutorService exec = Executors.newCachedThreadPool();
Exchanger<List<Fat>> xc = new Exchanger<>();
List<Fat>
producerList = new CopyOnWriteArrayList<>(),
consumerList = new CopyOnWriteArrayList<>();
exec.execute(new ExchangerProducer<>(xc,
BasicGenerator.create(Fat.class), producerList));
exec.execute(
new ExchangerConsumer<>(xc,consumerList));
TimeUnit.SECONDS.sleep(delay);
exec.shutdownNow();
}
} /* Output: (Sample)
Final value: Fat id: 29999
*///:~