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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.jrt;
import java.nio.channels.ServerSocketChannel;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A class used to listen on a network socket. A separate thread is
* used to accept connections and register them with the underlying
* transport thread. To create an acceptor you need to invoke the
* {@link Supervisor#listen listen} method in the {@link Supervisor}
* class.
**/
public class Acceptor {
private class Run implements Runnable {
public void run() {
try {
Acceptor.this.run();
} catch (Throwable problem) {
parent.handleFailure(problem, Acceptor.this);
}
}
}
private static Logger log = Logger.getLogger(Acceptor.class.getName());
private Thread thread = new Thread(new Run(), "<acceptor>");
private Transport parent;
private Supervisor owner;
private ServerSocketChannel serverChannel;
Acceptor(Transport parent, Supervisor owner,
Spec spec) throws ListenFailedException {
this.parent = parent;
this.owner = owner;
if (spec.malformed()) {
throw new ListenFailedException("Malformed spec");
}
try {
serverChannel = ServerSocketChannel.open();
serverChannel.configureBlocking(true);
if (spec.port() != 0) {
serverChannel.socket().setReuseAddress(true);
}
serverChannel.socket().bind(spec.address(), 500);
} catch (Exception e) {
if (serverChannel != null) {
try { serverChannel.socket().close(); } catch (Exception x) {}
}
throw new ListenFailedException("Listen failed", e);
}
thread.setDaemon(true);
thread.start();
}
/**
* Obtain the local port number this Acceptor is listening to. If
* this Acceptor is no longer listening (it has been shut down),
* -1 will be returned.
*
* @return listening port, or -1 if not listening
**/
public int port() {
if (!serverChannel.isOpen()) {
return -1;
}
return serverChannel.socket().getLocalPort();
}
/**
* Obtain the Spec for the local port and host interface this Acceptor
* is listening to. If this Acceptor is no longer listening (it has
* been shut down), null will be returned.
*
* @return listening spec, or null if not listening.
**/
public Spec spec() {
if (!serverChannel.isOpen()) {
return null;
}
return new Spec(serverChannel.socket().getInetAddress().getHostName(),
serverChannel.socket().getLocalPort());
}
private void run() {
while (serverChannel.isOpen()) {
try {
parent.addConnection(new Connection(parent, owner,
serverChannel.accept()));
parent.sync();
} catch (java.nio.channels.ClosedChannelException x) {
} catch (Exception e) {
log.log(Level.WARNING, "Error accepting connection", e);
}
}
}
/**
* Initiate controlled shutdown of the acceptor thread
*
* @return this object, to enable chaining with {@link #join join}
**/
public Acceptor shutdown() {
try {
serverChannel.socket().close();
} catch (Exception e1) {
log.log(Level.WARNING, "Error closing server socket", e1);
Thread.yield(); // throw some salt over the shoulder
try {
serverChannel.socket().close();
} catch (Exception e2) {
log.log(Level.WARNING, "Error closing server socket", e2);
Thread.yield(); // throw some salt over the shoulder
try {
serverChannel.socket().close();
} catch (Exception e3) {
log.log(Level.WARNING, "Error closing server socket", e3);
throw new Error("Error closing server socket 3 times", e3);
}
}
}
return this;
}
/**
* Wait for the acceptor thread to finish
**/
public void join() {
while (true) {
try {
thread.join();
return;
} catch (InterruptedException e) {}
}
}
}
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