/***
* Copyright 2002-2010 jamod development team
*
* 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 net.wimpi.modbus.net;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.ModbusCoupler;
import net.wimpi.modbus.ModbusIOException;
import net.wimpi.modbus.io.ModbusTransport;
import net.wimpi.modbus.msg.ModbusRequest;
import net.wimpi.modbus.msg.ModbusResponse;
import net.wimpi.modbus.util.SerialParameters;
/**
* Class that implements a ModbusTCPListener.<br>
* If listening, it accepts incoming requests
* passing them on to be handled.
*
* @author Dieter Wimberger
* @version @version@ (@date@)
*/
public class ModbusSerialListener {
//Members
private boolean m_Listening; //Flag for toggling listening/!listening
private SerialConnection m_SerialCon;
private static int c_RequestCounter = 0; //counter for amount of requests
/**
* Constructs a new <tt>ModbusSerialListener</tt> instance.
*
* @param params a <tt>SerialParameters</tt> instance.
*/
public ModbusSerialListener(SerialParameters params) {
m_SerialCon = new SerialConnection(params);
//System.out.println("Created connection.");
listen();
}//constructor
/**
* Listen to incoming messages.
*/
private void listen() {
try {
m_Listening = true;
m_SerialCon.open();
//System.out.println("Opened Serial connection.");
ModbusTransport transport = m_SerialCon.getModbusTransport();
do {
if (m_Listening) {
try {
//1. read the request
ModbusRequest request = transport.readRequest();
ModbusResponse response = null;
//test if Process image exists
if (ModbusCoupler.getReference().getProcessImage() == null) {
response =
request.createExceptionResponse(Modbus.ILLEGAL_FUNCTION_EXCEPTION);
} else {
response = request.createResponse();
}
if (Modbus.debug)
System.out.println("Request:" + request.getHexMessage());
if (Modbus.debug)
System.out.println("Response:" + response.getHexMessage());
transport.writeMessage(response);
count();
} catch (ModbusIOException ex) {
ex.printStackTrace();
continue;
}
}
//ensure nice multithreading behaviour on specific platforms
} while (true);
} catch (Exception e) {
//FIXME: this is a major failure, how do we handle this
e.printStackTrace();
}
}//listen
/**
* Sets the listening flag of this <tt>ModbusTCPListener</tt>.
*
* @param b true if listening (and accepting incoming connections),
* false otherwise.
*/
public void setListening(boolean b) {
m_Listening = b;
}//setListening
/**
* Tests if this <tt>ModbusTCPListener</tt> is listening
* and accepting incoming connections.
*
* @return true if listening (and accepting incoming connections),
* false otherwise.
*/
public boolean isListening() {
return m_Listening;
}//isListening
private void count() {
c_RequestCounter++;
if (c_RequestCounter == REQUESTS_TOGC) {
System.gc();
c_RequestCounter = 0;
}
}//count
private static final int REQUESTS_TOGC = 15;
}//class ModbusTCPListener