co.paralleluniverse.strands.channels.ThreadReceivePort 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.Strand;
import co.paralleluniverse.strands.channels.ReceivePort.EOFException;
import java.util.concurrent.TimeUnit;
/**
* This class is a simple convenience wrapper around {@link ReceivePort} that can be used by threads (as opposed to fibers). Its methods do not
* declare they throw {@code SuspendExecution}.
*
* @author pron
*/
public class ThreadReceivePort {
private final ReceivePort p;
/**
* Creates a new convenience wrapper for using a {@link ReceivePort} in a thread.
*
* @param p the {@link SendPort} to wrap.
*/
public ThreadReceivePort(ReceivePort p) {
this.p = p;
}
/**
* Retrieves a message from the channels, possibly blocking until one becomes available.
*
* @return a message, or {@code null} if the channel has been closed and no more messages await (see {@link #isClosed()}).
* @throws InterruptedException
*/
public Message receive() throws InterruptedException {
if (Strand.isCurrentFiber())
throw new IllegalStateException("This method cannot be called on a fiber");
try {
return p.receive();
} catch (SuspendExecution e) {
throw new AssertionError(e);
}
}
/**
* Retrieves a message from the channels, possibly blocking until one becomes available, but no longer than the specified timeout.
*
* @param timeout the maximum duration to block waiting for a message.
* @param unit the time unit of the timeout.
* @return a message, or {@code null} if the channel has been closed and no more messages await (see {@link #isClosed()}), or if
* the timeout has expired.
* @throws InterruptedException
*/
public Message receive(long timeout, TimeUnit unit) throws InterruptedException {
if (Strand.isCurrentFiber())
throw new IllegalStateException("This method cannot be called on a fiber");
try {
return p.receive(timeout, unit);
} catch (SuspendExecution e) {
throw new AssertionError(e);
}
}
/**
* Retrieves a message from the channel if one is available. This method never blocks.
*
* @return a message, or {@code null} if one is not immediately available.
*/
public Message tryReceive() {
return p.tryReceive();
}
/**
* Closes the channel so that no more messages could be sent to it. Messages already sent to the channel will still be received.
*/
public void close() {
p.close();
}
/**
* Tests whether the channel has been closed and no more messages await in the channel. If this method returns {@code true} all
* future calls to {@link #receive() } are guaranteed to return {@code null}, and calls to {@code receive} on a primitive channel
* will throw an {@link EOFException EOFException}.
*
* @return {@code true} if the channels has been closed and no more messages will be received; {@code false} otherwise.
*/
public boolean isClosed() {
return p.isClosed();
}
@Override
public final int hashCode() {
return p.hashCode();
}
@Override
public final boolean equals(Object obj) {
return p.equals(obj);
}
@Override
public final String toString() {
return p.toString();
}
}