co.paralleluniverse.strands.channels.FlatMappingReceivePort 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.concurrent.TimeUnit;
/**
*
* @author pron
*/
public class FlatMappingReceivePort extends DelegatingReceivePort1 implements ReceivePort {
private final Function> f;
private ReceivePort port;
public FlatMappingReceivePort(ReceivePort target, Function> f) {
super(target);
if (f == null)
throw new IllegalArgumentException("f can't be null");
this.f = f;
}
public FlatMappingReceivePort(ReceivePort target) {
this(target, null);
}
@Override
@SuppressWarnings("empty-statement")
public T receive() throws SuspendExecution, InterruptedException {
for (;;) {
T m = (port != null ? port.receive() : null);
if (m != null)
return m;
assert port == null || port.isClosed();
S m0 = target.receive();
if (m0 == null) // closed
return null;
this.port = map(m0);
}
}
@Override
public T receive(long timeout, TimeUnit unit) throws SuspendExecution, InterruptedException {
long left = unit.toNanos(timeout);
final long deadline = System.nanoTime() + left;
for (;;) {
T m = (port != null ? port.receive(left, TimeUnit.NANOSECONDS) : null);
if (m != null)
return m;
left = deadline - System.nanoTime();
if (left <= 0)
return null;
assert port == null || port.isClosed();
S m0 = target.receive(left, TimeUnit.NANOSECONDS);
if (m0 == null)
return null;
this.port = map(m0);
left = deadline - System.nanoTime();
}
}
@Override
public T tryReceive() {
for (;;) {
if (port != null && !port.isClosed())
return port.tryReceive();
S m0 = target.tryReceive();
if (m0 == null)
return null;
this.port = map(m0);
}
}
@Override
public T receive(Timeout timeout) throws SuspendExecution, InterruptedException {
return receive(timeout.nanosLeft(), TimeUnit.NANOSECONDS);
}
protected ReceivePort map(S m) {
return f.apply(m);
}
@Override
public boolean isClosed() {
return target.isClosed() && (port == null || port.isClosed());
}
}