com.ghgande.j2mod.modbus.msg.ReadInputDiscretesResponse Maven / Gradle / Ivy
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/*
* Copyright 2002-2016 jamod & j2mod development teams
*
* 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 com.ghgande.j2mod.modbus.msg;
import com.ghgande.j2mod.modbus.Modbus;
import com.ghgande.j2mod.modbus.util.BitVector;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
/**
* Class implementing a ReadInputDiscretesResponse.
* The implementation directly correlates with the class 1
* function read input discretes (FC 2). It encapsulates
* the corresponding response message.
*
* Input Discretes are understood as bits that cannot be
* manipulated (i.e. set or unset).
*
* @author Dieter Wimberger
* @author Steve O'Hara (4NG)
* @version 2.0 (March 2016)
*/
public class ReadInputDiscretesResponse extends ModbusResponse {
//instance attributes
private int bitCount;
private BitVector discretes;
/**
* Constructs a new ReadInputDiscretesResponse
* instance.
*/
public ReadInputDiscretesResponse() {
super();
setFunctionCode(Modbus.READ_INPUT_DISCRETES);
}
/**
* Constructs a new ReadInputDiscretesResponse
* instance with a given count of input discretes
* (i.e. bits).
*
* @param count the number of bits to be read.
*/
public ReadInputDiscretesResponse(int count) {
super();
setFunctionCode(Modbus.READ_INPUT_DISCRETES);
setBitCount(count);
}
/**
* Returns the number of bits (i.e. input discretes)
* read with the request.
*
* @return the number of bits that have been read.
*/
public int getBitCount() {
return bitCount;
}
/**
* Sets the number of bits in this response.
*
* @param count the number of response bits as int.
*/
public void setBitCount(int count) {
bitCount = count;
discretes = new BitVector(count);
//set correct length, without counting unitid and fc
setDataLength(discretes.byteSize() + 1);
}
/**
* Returns the BitVector that stores
* the collection of bits that have been read.
*
*
* @return the BitVector holding the
* bits that have been read.
*/
public BitVector getDiscretes() {
return discretes;
}
/**
* Convenience method that returns the state
* of the bit at the given index.
*
*
* @param index the index of the input discrete
* for which the status should be returned.
*
* @return true if set, false otherwise.
*
* @throws IndexOutOfBoundsException if the
* index is out of bounds
*/
public boolean getDiscreteStatus(int index) throws IndexOutOfBoundsException {
return discretes.getBit(index);
}
/**
* Sets the status of the given input discrete.
*
* @param index the index of the input discrete to be set.
* @param b true if to be set, false if to be reset.
*
* @throws IndexOutOfBoundsException if the given index exceeds bounds.
*/
public void setDiscreteStatus(int index, boolean b) throws IndexOutOfBoundsException {
discretes.setBit(index, b);
}
@Override
public void writeData(DataOutput dout) throws IOException {
dout.writeByte(discretes.byteSize());
dout.write(discretes.getBytes(), 0, discretes.byteSize());
}
@Override
public void readData(DataInput din) throws IOException {
int count = din.readUnsignedByte();
byte[] data = new byte[count];
for (int k = 0; k < count; k++) {
data[k] = din.readByte();
}
//decode bytes into bitvector
discretes = BitVector.createBitVector(data);
if (discretes != null) {
bitCount = discretes.size();
}
//update data length
setDataLength(count + 1);
}
@Override
public byte[] getMessage() {
byte[] result;
int len = 1 + discretes.byteSize();
result = new byte[len];
result[0] = (byte)discretes.byteSize();
System.arraycopy(discretes.getBytes(), 0, result, 1, discretes.byteSize());
return result;
}
}