/***
* 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.msg;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.ModbusCoupler;
import net.wimpi.modbus.procimg.IllegalAddressException;
import net.wimpi.modbus.procimg.InputRegister;
import net.wimpi.modbus.procimg.ProcessImage;
/**
* Class implementing a <tt>ReadInputRegistersRequest</tt>.
* The implementation directly correlates with the class 0
* function <i>read multiple registers (FC 4)</i>. It
* encapsulates the corresponding request message.
*
* @author Dieter Wimberger
* @version @version@ (@date@)
*/
public final class ReadInputRegistersRequest
extends ModbusRequest {
//instance attributes
private int m_Reference;
private int m_WordCount;
/**
* Constructs a new <tt>ReadInputRegistersRequest</tt>
* instance.
*/
public ReadInputRegistersRequest() {
super();
setFunctionCode(Modbus.READ_INPUT_REGISTERS);
//4 bytes (unit id and function code is excluded)
setDataLength(4);
}//constructor
/**
* Constructs a new <tt>ReadInputRegistersRequest</tt>
* instance with a given reference and count of words
* to be read.
* <p>
* @param ref the reference number of the register
* to read from.
* @param count the number of words to be read.
*/
public ReadInputRegistersRequest(int ref, int count) {
super();
setFunctionCode(Modbus.READ_INPUT_REGISTERS);
//4 bytes (unit id and function code is excluded)
setDataLength(4);
setReference(ref);
setWordCount(count);
}//constructor
public ModbusResponse createResponse() {
ReadInputRegistersResponse response = null;
InputRegister[] inpregs = null;
//1. get process image
ProcessImage procimg = ModbusCoupler.getReference().getProcessImage();
//2. get input registers range
try {
inpregs = procimg.getInputRegisterRange(this.getReference(), this.getWordCount());
} catch (IllegalAddressException iaex) {
return createExceptionResponse(Modbus.ILLEGAL_ADDRESS_EXCEPTION);
}
response = new ReadInputRegistersResponse(inpregs);
//transfer header data
if (!isHeadless()) {
response.setTransactionID(this.getTransactionID());
response.setProtocolID(this.getProtocolID());
} else {
response.setHeadless();
}
response.setUnitID(this.getUnitID());
response.setFunctionCode(this.getFunctionCode());
return response;
}//createResponse
/**
* Sets the reference of the register to start reading
* from with this <tt>ReadInputRegistersRequest</tt>.
* <p>
* @param ref the reference of the register
* to start reading from.
*/
public void setReference(int ref) {
m_Reference = ref;
//setChanged(true);
}//setReference
/**
* Returns the reference of the register to to start
* reading from with this
* <tt>ReadInputRegistersRequest</tt>.
* <p>
* @return the reference of the register
* to start reading from as <tt>int</tt>.
*/
public int getReference() {
return m_Reference;
}//getReference
/**
* Sets the number of words to be read with this
* <tt>ReadInputRegistersRequest</tt>.
* <p>
* @param count the number of words to be read.
*/
public void setWordCount(int count) {
m_WordCount = count;
//setChanged(true);
}//setWordCount
/**
* Returns the number of words to be read with this
* <tt>ReadInputRegistersRequest</tt>.
* <p>
* @return the number of words to be read as
* <tt>int</tt>.
*/
public int getWordCount() {
return m_WordCount;
}//getWordCount
public void writeData(DataOutput dout)
throws IOException {
dout.writeShort(m_Reference);
dout.writeShort(m_WordCount);
}//writeData
public void readData(DataInput din)
throws IOException {
m_Reference = din.readUnsignedShort();
m_WordCount = din.readUnsignedShort();
}//readData
}//class ReadInputRegistersRequest