BenqProjectorSerialTransport.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.benqprojector.internal.transport;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import gnu.io.NRSerialPort;

/**
 * Implement the serial based transport for communicating with a Benq projector
 *
 * @author Kristian Larsson (kll)
 * @since 1.8.0
 */
public class BenqProjectorSerialTransport implements BenqProjectorTransport {

    private static final Logger logger = LoggerFactory.getLogger(BenqProjectorSerialTransport.class);

    /**
     * Serial device to use
     */
    private String serialDevice = "";
    // TODO: what should default be?
    private int serialSpeed = 57600;

    private NRSerialPort serialPort = null;
    private PrintWriter projectorWriter = null;
    private BufferedReader projectorReader = null;
    private boolean retryAttempt = false;

    private boolean serialConnect() {
        logger.debug("Running connection setup");
        try {
            logger.debug("Setting up socket connection to " + this.serialDevice);
            this.serialPort = new NRSerialPort(this.serialDevice, this.serialSpeed);
            this.serialPort.connect();

            this.projectorReader = new BufferedReader(new InputStreamReader(this.serialPort.getInputStream()));
            this.projectorWriter = new PrintWriter(this.serialPort.getOutputStream(), true);

            logger.debug("Serial connection setup successfully!");
            return true;
        } catch (Exception e) {
            logger.error("Unable to connect to device: " + this.serialDevice, e);
        }
        return false;
    }

    @Override
    public boolean setupConnection(String connectionParams) {
        boolean setupOK = false;
        if (this.serialPort == null) {
            /* parse connection paramters in the format device:speed */
            String[] deviceIdParts = connectionParams.split(":");
            if (deviceIdParts.length == 1) {
                logger.debug("Using default speed: " + this.serialSpeed);
                this.serialDevice = deviceIdParts[0];
            } else if (deviceIdParts.length == 2) {
                this.serialDevice = deviceIdParts[0];
                this.serialSpeed = Integer.parseInt(deviceIdParts[1]);
            } else {
                return false;
            }

            setupOK = this.serialConnect();
        } else {
            logger.debug("Port is already setup");
        }
        return setupOK;
    }

    @Override
    public void closeConnection() {
        try {
            this.serialPort.disconnect();
        } catch (Exception e) {
            logger.error("Trying to close socket resulted in IO exception: " + e.getMessage());
        }
        this.serialPort = null;
    }

    @Override
    public String sendCommandExpectResponse(String cmd) {
        String respStr = "";
        String tmp;
        if (this.projectorWriter != null) {
            this.projectorWriter.printf("%s", cmd);
            logger.debug("Sent command '" + cmd.replace("\r", "") + "'");
            try {
                tmp = this.projectorReader.readLine();
                while (tmp != null) {
                    if (tmp.startsWith("*") == true && tmp.endsWith("#")) {
                        /* got response */
                        logger.debug("Response: '" + tmp + "'");
                        respStr = tmp;
                        break;
                    }
                    tmp = this.projectorReader.readLine();
                }
            } catch (Exception e) {
                logger.error("IO Exception while reading response from projector: " + e.getMessage());
                if (retryAttempt == false) {
                    this.closeConnection();
                    if (this.serialConnect()) {
                        logger.debug("Reconnect successful - retrying transmission");
                        /* set flag to stop us ending up here again and so avoid infinite recursion */
                        retryAttempt = true;
                        sendCommandExpectResponse(cmd);
                    } else {
                        logger.error("Attempt to reconnect after IOException failed: " + e.getMessage());
                    }
                    /* reset flag */
                    retryAttempt = false;
                }
            }
        } else {
            logger.debug("Not sending command to projector as connection is not setup yet.");
        }

        return respStr;
    }

}