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/*
* Copyright (c) 2014, 2015 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.netconf.sal.streams.websockets;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static java.util.Objects.requireNonNull;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import org.opendaylight.netconf.sal.streams.listeners.Notificator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* {@link WebSocketServer} is the singleton responsible for starting and stopping the
* web socket server.
*/
public final class WebSocketServer implements Runnable {
private static final Logger LOG = LoggerFactory.getLogger(WebSocketServer.class);
private static final String DEFAULT_ADDRESS = "0.0.0.0";
private static WebSocketServer instance = null;
private final String address;
private final int port;
private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup;
private WebSocketServer(final String address, final int port) {
this.address = address;
this.port = port;
}
/**
* Create singleton instance of {@link WebSocketServer}.
*
* @param port TCP port used for this server
* @return instance of {@link WebSocketServer}
*/
private static WebSocketServer createInstance(final int port) {
instance = createInstance(DEFAULT_ADDRESS, port);
return instance;
}
public static WebSocketServer createInstance(final String address, final int port) {
checkState(instance == null, "createInstance() has already been called");
checkArgument(port >= 1024, "Privileged port (below 1024) is not allowed");
instance = new WebSocketServer(requireNonNull(address, "Address cannot be null."), port);
LOG.info("Created WebSocketServer on {}:{}", address, port);
return instance;
}
/**
* Get the websocket of TCP port.
*
* @return websocket TCP port
*/
public int getPort() {
return port;
}
/**
* Get instance of {@link WebSocketServer} created by {@link #createInstance(int)}.
*
* @return instance of {@link WebSocketServer}
*/
public static WebSocketServer getInstance() {
return requireNonNull(instance, "createInstance() must be called prior to getInstance()");
}
/**
* Get instance of {@link WebSocketServer} created by {@link #createInstance(int)}.
* If an instance doesnt exist create one with the provided fallback port.
*
* @return instance of {@link WebSocketServer}
*/
public static WebSocketServer getInstance(final int fallbackPort) {
if (instance != null) {
return instance;
}
LOG.warn("No instance for WebSocketServer found, creating one with a fallback port: {}", fallbackPort);
return createInstance(fallbackPort);
}
/**
* Destroy the existing instance.
*/
public static void destroyInstance() {
checkState(instance != null, "createInstance() must be called prior to destroyInstance()");
instance.stop();
instance = null;
LOG.info("Destroyed WebSocketServer.");
}
@Override
@SuppressWarnings("checkstyle:IllegalCatch")
public void run() {
bossGroup = new NioEventLoopGroup();
workerGroup = new NioEventLoopGroup();
try {
final ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
.childHandler(new WebSocketServerInitializer());
final Channel channel = serverBootstrap.bind(address, port).sync().channel();
LOG.info("Web socket server started at address {}, port {}.", address, port);
channel.closeFuture().sync();
} catch (final InterruptedException e) {
LOG.error("Web socket server encountered an error during startup attempt on port {}", port, e);
} catch (Throwable throwable) {
// sync() re-throws exceptions declared as Throwable, so the compiler doesn't see them
LOG.error("Error while binding to address {}, port {}", address, port, throwable);
throw throwable;
} finally {
stop();
}
}
/**
* Stops the web socket server and removes all listeners.
*/
private void stop() {
LOG.info("Stopping the web socket server instance on port {}", port);
Notificator.removeAllListeners();
if (bossGroup != null) {
bossGroup.shutdownGracefully();
bossGroup = null;
}
if (workerGroup != null) {
workerGroup.shutdownGracefully();
workerGroup = null;
}
}
}
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