WriteMultipleCoilsRequest.java

/***
 * 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.DigitalOut;
import net.wimpi.modbus.procimg.IllegalAddressException;
import net.wimpi.modbus.procimg.ProcessImage;
import net.wimpi.modbus.util.BitVector;

/**
 * Class implementing a <tt>WriteMultipleCoilsRequest</tt>.
 * The implementation directly correlates with the class 1
 * function <i>write multiple coils (FC 15)</i>. It encapsulates
 * the corresponding request message.
 * <p/>
 * Coils are understood as bits that can be manipulated
 * (i.e. set or unset).
 *
 * @author Dieter Wimberger
 * @version @version@ (@date@)
 */
public final class WriteMultipleCoilsRequest extends ModbusRequest {

    // instance attributes
    private int m_Reference;
    private BitVector m_Coils;

    /**
     * Constructs a new <tt>WriteMultipleCoilsRequest</tt>
     * instance.
     */
    public WriteMultipleCoilsRequest() {
        super();
        setFunctionCode(Modbus.WRITE_MULTIPLE_COILS);
        // 5 bytes (unit id and function code is excluded)
        setDataLength(5);
    }// constructor

    /**
     * Constructs a new <tt>WriteMultipleCoilsRequest</tt>
     * instance with a given reference and count of coils
     * (i.e. bits) to be written.
     * <p/>
     *
     * @param ref the index of the first coil to be written.
     * @param count the number of coils to be written.
     */
    public WriteMultipleCoilsRequest(int ref, int count) {
        super();
        setFunctionCode(Modbus.WRITE_MULTIPLE_COILS);
        setReference(ref);
        m_Coils = new BitVector(count);
        setDataLength(m_Coils.byteSize() + 5);
    }// constructor

    /**
     * Constructs a new <tt>WriteMultipleCoilsRequest</tt>
     * instance with given reference and coil status.
     *
     * @param ref the index of the first coil to be written.
     * @param bv the coils to be written.
     */
    public WriteMultipleCoilsRequest(int ref, BitVector bv) {
        super();
        setFunctionCode(Modbus.WRITE_MULTIPLE_COILS);
        setReference(ref);
        m_Coils = bv;
        setDataLength(m_Coils.byteSize() + 5);
    }// constructor

    @Override
    public ModbusResponse createResponse() {
        WriteMultipleCoilsResponse response = null;
        DigitalOut douts[] = null;

        // 1. get process image
        ProcessImage procimg = ModbusCoupler.getReference().getProcessImage();
        // 2. get coil range
        try {
            douts = procimg.getDigitalOutRange(m_Reference, m_Coils.size());
            // 3. set coils
            for (int i = 0; i < douts.length; i++) {
                douts[i].set(m_Coils.getBit(i));
            }
        } catch (IllegalAddressException iaex) {
            return createExceptionResponse(Modbus.ILLEGAL_ADDRESS_EXCEPTION);
        }
        response = new WriteMultipleCoilsResponse(m_Reference, m_Coils.size());

        // 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>ReadCoilsRequest</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>ReadCoilsRequest</tt>.
     * <p/>
     *
     * @return the reference of the register
     *         to start reading from as <tt>int</tt>.
     */
    public int getReference() {
        return m_Reference;
    }// getReference

    /**
     * Returns the number of bits (i.e. input discretes)
     * read with the request.
     * <p/>
     *
     * @return the number of bits that have been read.
     */
    public int getBitCount() {
        if (m_Coils == null) {
            return 0;
        } else {
            return m_Coils.size();
        }
    }// getBitCount

    /**
     * Returns the number of bytes required for packing the
     * coil bits.
     *
     * @return the number of bytes required for packing the coil bits.
     */
    public int getByteCount() {
        return m_Coils.byteSize();
    }// getByteCount

    /**
     * Returns the status of the given coil.
     *
     * @param index the index of the coil to be tested.
     * @return true if set, false otherwise.
     * @throws IndexOutOfBoundsException if the given index is out of bounds.
     */
    public boolean getCoilStatus(int index) throws IndexOutOfBoundsException {
        return m_Coils.getBit(index);
    }// getCoilStatus

    /**
     * Sets the coil status of the given coil.
     *
     * @param index the index of the coil to be set/reset.
     * @param b true if to be set, false for reset.
     * @throws IndexOutOfBoundsException if the given index is out of bounds.
     */
    public void setCoilStatus(int index, boolean b) throws IndexOutOfBoundsException {
        m_Coils.setBit(index, b);
    }// setCoilStatus

    /**
     * Returns the <tt>BitVector</tt> instance holding coil
     * status information.
     *
     * @return the coils status as <tt>BitVector</tt> instance.
     */
    public BitVector getCoils() {
        return m_Coils;
    }// getCoils

    /**
     * Sets the <tt>BitVector</tt> instance holding coil
     * status information.
     *
     * @param bv a <tt>BitVector</tt> instance holding coil status info.
     */
    public void setCoils(BitVector bv) {
        m_Coils = bv;
    }// setCoils

    @Override
    public void writeData(DataOutput dout) throws IOException {
        dout.writeShort(m_Reference);
        dout.writeShort(m_Coils.size());
        dout.writeByte(m_Coils.byteSize());
        dout.write(m_Coils.getBytes());
    }// writeData

    @Override
    public void readData(DataInput din) throws IOException {

        m_Reference = din.readUnsignedShort();
        int bitcount = din.readUnsignedShort();
        int count = din.readUnsignedByte();
        byte[] data = new byte[count];
        for (int k = 0; k < count; k++) {
            data[k] = din.readByte();
        }
        // decode bytes into bitvector, sets data and bitcount
        m_Coils = BitVector.createBitVector(data, bitcount);

        // update data length
        setDataLength(count + 5);
    }// readData

}// class WriteMultipleCoilsRequest