/*
* 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 java.util.concurrent.TimeUnit;
/**
*
* @author pron
*/
abstract class ReceivePortTransformer<S, T> extends DelegatingReceivePort1<S, T> implements ReceivePort<T> {
public ReceivePortTransformer(ReceivePort<S> target) {
super(target);
}
@Override
@SuppressWarnings("empty-statement")
public T receive() throws SuspendExecution, InterruptedException {
for (;;) {
S m0 = target.receive();
if (m0 == null) // closed
return null;
T m = transform(m0);
if (m != null)
return m;
}
}
@Override
public T tryReceive() {
for (;;) {
S m0 = target.tryReceive();
if (m0 == null)
return null;
T m = transform(m0);
if (m != null)
return m;
}
}
@Override
public T receive(long timeout, TimeUnit unit) throws SuspendExecution, InterruptedException {
long left = unit.toNanos(timeout);
final long deadline = System.nanoTime() + left;
for (;;) {
S m0 = target.receive(left, TimeUnit.NANOSECONDS);
if (m0 == null)
return null;
T m = transform(m0);
if (m != null)
return m;
left = deadline - System.nanoTime();
}
}
@Override
public T receive(Timeout timeout) throws SuspendExecution, InterruptedException {
return receive(timeout.nanosLeft(), TimeUnit.NANOSECONDS);
}
protected abstract T transform(S m);
}