co.paralleluniverse.strands.channels.ZippingReceivePort Maven / Gradle / Ivy
/*
* Quasar: lightweight threads and actors for the JVM.
* Copyright (c) 2013-2014, Parallel Universe Software Co. All rights reserved.
*
* This program and the accompanying materials are dual-licensed under
* either the terms of the Eclipse Public License v1.0 as published by
* the Eclipse Foundation
*
* or (per the licensee's choosing)
*
* under the terms of the GNU Lesser General Public License version 3.0
* as published by the Free Software Foundation.
*/
package co.paralleluniverse.strands.channels;
import co.paralleluniverse.fibers.SuspendExecution;
import co.paralleluniverse.strands.Timeout;
import com.google.common.base.Function;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;
/**
* Single consumer
*
* @author pron
*/
public class ZippingReceivePort implements ReceivePort {
private final Function f;
private final ReceivePort[] targets;
private Object[] ms;
public ZippingReceivePort(Function f, ReceivePort... targets) {
this(f, Arrays.asList(targets));
}
public ZippingReceivePort(Function f, List> targets) {
this.f = f;
this.targets = targets.toArray(new ReceivePort[targets.size()]);
this.ms = new Object[targets.size()];
}
public ZippingReceivePort(ReceivePort... targets) {
this(null, targets);
}
public ZippingReceivePort(List> targets) {
this(null, targets);
}
@Override
@SuppressWarnings("empty-statement")
public Message receive() throws SuspendExecution, InterruptedException {
for (int i = 0; i < targets.length; i++) {
if (ms[i] == null) {
Object m = targets[i].receive();
if (m == null) // closed
return null;
ms[i] = m;
}
}
return transformAndReset();
}
@Override
public Message tryReceive() {
for (int i = 0; i < targets.length; i++) {
if (ms[i] == null) {
Object m = targets[i].tryReceive();
if (m == null)
return null;
ms[i] = m;
}
}
return transformAndReset();
}
@Override
public Message receive(long timeout, TimeUnit unit) throws SuspendExecution, InterruptedException {
long left = unit.toNanos(timeout);
final long deadline = System.nanoTime() + left;
for (int i = 0; i < targets.length; i++) {
if (ms[i] == null) {
Object m = targets[i].receive(left, TimeUnit.NANOSECONDS);
if (m == null)
return null;
ms[i] = m;
left = deadline - System.nanoTime();
}
}
return transformAndReset();
}
@Override
public Message receive(Timeout timeout) throws SuspendExecution, InterruptedException {
return receive(timeout.nanosLeft(), TimeUnit.NANOSECONDS);
}
private Message transformAndReset() {
final Object[] ms1 = copy(ms);
Arrays.fill(ms, null);
return transform(ms1);
}
private static Object[] copy(Object[] array) {
Object[] array2 = new Object[array.length];
System.arraycopy(array, 0, array2, 0, array.length);
return array2;
}
@Override
public void close() {
for (ReceivePort c : targets)
c.close();
}
@Override
public boolean isClosed() {
for (ReceivePort c : targets) {
if (c.isClosed())
return true;
}
return false;
}
protected Message transform(Object[] ms) {
if (f != null)
return f.apply(ms);
throw new UnsupportedOperationException();
}
}