org.jppf.comm.recovery.ServerConnection Maven / Gradle / Ivy
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/*
* JPPF.
* Copyright (C) 2005-2015 JPPF Team.
* http://www.jppf.org
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jppf.comm.recovery;
import java.net.Socket;
import org.jppf.comm.socket.*;
import org.jppf.utils.*;
import org.slf4j.*;
/**
* Instances of this class represent connections to a server from a remote peer.
* They are used to send, at regular intervals, a request to the distant peer and check
* if the expected response is received. If the response is incorrect or not received at all,
* then the connection is considered broken and closed on the server side.
*
The main goal is to detect network connections broken due to hardware failures on
* the remote peer side, which cannot be detected otherwise.
* @author Laurent Cohen
*/
public class ServerConnection extends AbstractRecoveryConnection
{
/**
* Logger for this class.
*/
private static Logger log = LoggerFactory.getLogger(ServerConnection.class);
/**
* Determines whether the debug level is enabled in the log configuration, without the cost of a method call.
*/
private static boolean debugEnabled = LoggingUtils.isDebugEnabled(log);
/**
* Initialize this connection with the specified socket.
* @param socket the socket connected to a client.
* @param maxRetries the maximum number of failed write/read attempts on a connection before the remote peer is considered dead.
* @param socketReadTimeout the maximum wait time on a response from the remote peer.
* @throws Exception if any error occurs while initializing the socket connection.
*/
public ServerConnection(final Socket socket, final int maxRetries, final int socketReadTimeout) throws Exception
{
this.ok = true;
this.initialized = false;
this.maxRetries = maxRetries;
this.socketReadTimeout = socketReadTimeout;
socketWrapper = new BootstrapSocketClient(socket);
}
/**
* {@inheritDoc}
*/
@Override
public synchronized void run()
{
if (!isOk()) return;
if (!initialized) performHandshake();
else performCheck();
}
/**
* Perform the initial handshake with the remote peer.
*/
private void performHandshake()
{
String response = doSendReceive("handshake");
if (!isOk()) return;
int idx = response.indexOf(';');
if (idx < 0)
{
setOk(false);
return;
}
uuid = response.substring(idx + 1);
if (debugEnabled) log.debug("got uuid=" + uuid);
}
/**
* Perform the initial handshake with the remote peer.
*/
private void performCheck()
{
doSendReceive("check");
}
/**
* Send a string to the remote peer and receive a string back.
* If any exception occurs while sending or receiving, the connection is considered broken.
* @param message the string message to send to the remote peer.
* @return the response as a string.
*/
private String doSendReceive(final String message)
{
String response = null;
try
{
if (socketWrapper == null) return null;
sendMessage(message);
response = receiveMessage();
//sendMessage("final");
}
catch (Exception e)
{
close();
if (debugEnabled) log.debug("error checking " + this, e);
}
return response;
}
/**
* Close this server connection and release the resources it is using.
*/
@Override
public synchronized void close()
{
try
{
if (socketWrapper != null)
{
SocketWrapper tmp = socketWrapper;
socketWrapper = null;
setOk(false);
tmp.close();
}
}
catch (Exception e)
{
if (debugEnabled) log.debug("error closing " + this, e);
}
}
/**
* {@inheritDoc}
*/
@Override
public String toString()
{
return StringUtils.build("ServerConnection[socketWrapper=", socketWrapper, ", ok=", ok, ", initialized=", initialized, ", uuid=", uuid, "]");
}
}