InsteonHubSerialMessageBuilder.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.insteonhub.internal.hardware.api.serial;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;
import org.openhab.binding.insteonhub.internal.hardware.InsteonHubAdjustmentType;
import org.openhab.binding.insteonhub.internal.hardware.InsteonHubMsgConst;

/**
 * Builds INSTEON Hub messages per spec.
 *
 * @author Eric Thill
 * @since 1.4.0
 */
public class InsteonHubSerialMessageBuilder {

    public static final int STD_MSG_SIZE = 8;
    private static final byte DEFAULT_FLAG = 0x0F;
    public static InsteonHubSerialMessageBuilder INSTANCE = new InsteonHubSerialMessageBuilder();

    public static InsteonHubSerialMessageBuilder getInstance() {
        return INSTANCE;
    }

    private InsteonHubSerialMessageBuilder() {

    }

    public byte[] buildRequestLevelMessage(byte[] msgBuffer, String device) {
        return buildStandardMessage(msgBuffer, device, DEFAULT_FLAG, InsteonHubMsgConst.CMD1_STATUS_REQUEST,
                (byte) 0x02);
    }

    public byte[] buildFastPowerMessage(byte[] msgBuffer, String device, boolean power) {
        byte cmd1 = power ? InsteonHubMsgConst.CMD1_ON_FAST : InsteonHubMsgConst.CMD1_OFF_FAST;
        return buildStandardMessage(msgBuffer, device, DEFAULT_FLAG, cmd1, InsteonHubMsgConst.CMD2_NO_VALUE);
    }

    public byte[] buildSetLevelMessage(byte[] msgBuffer, String device, int level) {
        byte cmd1 = level > 0 ? InsteonHubMsgConst.CMD1_ON : InsteonHubMsgConst.CMD1_OFF;
        return buildStandardMessage(msgBuffer, device, DEFAULT_FLAG, cmd1, (byte) level);
    }

    public byte[] buildStartDimBrtMessage(byte[] msgBuffer, String device, InsteonHubAdjustmentType type) {
        byte cmd2 = type == InsteonHubAdjustmentType.DIM ? InsteonHubMsgConst.CMD2_DIM : InsteonHubMsgConst.CMD2_BRT;
        return buildStandardMessage(msgBuffer, device, DEFAULT_FLAG, InsteonHubMsgConst.CMD1_START_DIM_BRT, cmd2);
    }

    public byte[] buildStopDimBrtMessage(byte[] msgBuffer, String device) {
        return buildStandardMessage(msgBuffer, device, DEFAULT_FLAG, InsteonHubMsgConst.CMD1_STOP_DIM_BRT,
                InsteonHubMsgConst.CMD2_NO_VALUE);
    }

    private byte[] buildStandardMessage(byte[] msgBuffer, String device, int flag, byte cmd1, byte cmd2) {
        // check to make sure reuse-buffer is large enough. if not, create a new
        // one to use.
        if (msgBuffer == null || msgBuffer.length < STD_MSG_SIZE) {
            msgBuffer = new byte[STD_MSG_SIZE];
        }

        // populate message
        msgBuffer[0] = InsteonHubMsgConst.STX;
        msgBuffer[1] = InsteonHubMsgConst.SND_CODE_SEND_INSTEON_STD_OR_EXT_MSG;
        try {
            System.arraycopy(Hex.decodeHex(device.toCharArray()), 0, msgBuffer, 2, 3);
        } catch (DecoderException e) {
            throw new IllegalArgumentException("Bad device id: " + device, e);
        }
        msgBuffer[5] = (byte) flag;
        msgBuffer[6] = cmd1;
        msgBuffer[7] = cmd2;
        return msgBuffer;
    }
}