DigitalMessage.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.tacmi.internal.message;

import org.openhab.core.library.types.OnOffType;
import org.slf4j.Logger;

/**
 * This class can be used to decode the digital values received in a messag and
 * also to create a new DigitalMessage used to send ON/OFF to an digital CAN
 * Input port
 *
 * @author Timo Wendt
 * @since 1.8.0
 */
public final class DigitalMessage extends Message {

    public DigitalMessage(byte[] raw) {
        super(raw);
    }

    /**
     * Create a new message to be sent to the CMI. It is only supported to use
     * the first port for each CAN node. This is due to the fact that all
     * digital port for the specific CAN node are send within a single message.
     */
    public DigitalMessage(byte canNode, boolean state) {
        super(canNode, (byte) 0);
        logger.debug("DigitalMessage: canNode: {}, podNumber: {}", this.canNode, this.podNumber);
        int value = state ? 1 : 0;
        setValue(0, value, 0);
    }

    /**
     * Get the state of the specified port number.
     * 
     * @param portNumber
     * @return
     */
    public boolean getPortState(int portNumber) {
        return getBit(getValue(0), portNumber - 1);
    }

    /**
     * Get the state as OnOffType for Item.
     * 
     * @param portNumber
     * @return
     */
    public OnOffType getPortStateAsOnOffType(int portNumber) {
        boolean state = getPortState(portNumber);
        return state ? OnOffType.ON : OnOffType.OFF;
    }

    /**
     * Read the specified bit from the short value holding the states of all 16
     * ports.
     * 
     * @param portBits
     * @param portBit
     * @return
     */
    private boolean getBit(int portBits, int portBit) {
        int result = (portBits >> portBit) & 0x1;
        return result == 1 ? true : false;
    }

    /**
     * Set the specified bit to the defined value. Only used when sending data.
     * 
     * @param portBits
     * @param portBit
     * @param state
     * @return
     */
    private int setBit(int portBits, int portBit, boolean state) {
        portBits = (1 << portBit) | portBits;
        return portBits;
    }

    /**
     * Check if message contains a value for the specified port number. For
     * digital messages this is always true as all ports are send in
     * a single message
     * 
     * @param portNumber
     * @return
     */
    @Override
    public boolean hasPortnumber(int portNumber) {
        return true;
    }

    @Override
    public void debug(Logger logger) {
    }

    @Override
    public MessageType getType() {
        return MessageType.D;
    }

}