Demo.java

Demo.java

package fr.free.mdwhatever.arduino.maven;

import gnu.io.CommPortIdentifier;
import gnu.io.NoSuchPortException;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;

import java.io.IOException;
import java.net.URL;

/**
 * 
 */
public class Demo {

	/**
	 * The port on which your arduino is plugged
	 */
	private static final String PORT_NAME = "/dev/tty.usbmodemfd131";
	/**
	 * Milliseconds to block while waiting for port open
	 */
	private static final int TIME_OUT = 2000;
	/**
	 * Default bits per second for COM port.
	 */
	private static final int DATA_RATE = 9600;
	/**
	 * The serial port used for communicating with arduino
	 */
	private SerialPort serialPort;

	/**
	 * Loads the jnilib
	 */
	public static void loadJniLib() {
		// loads the jnilib from the source folder "src/main/resources"
		URL url = Demo.class.getResource("/librxtxSerial.jnilib");

		try {
			System.load(url.getPath());
		}
		catch (UnsatisfiedLinkError unsatisfiedLinkError) {
			// native code library failed to load.
			unsatisfiedLinkError.printStackTrace();
		}
	}

	/**
	 * Will initialize the serial connection with your arduino.
	 */
	public void initialize() {
		// initializes the port identifier
		CommPortIdentifier portId = null;
		try {
			portId = CommPortIdentifier.getPortIdentifier(PORT_NAME);
		}
		catch (NoSuchPortException e1) {
			// if this exception occurs, it means the PORT_NAME constant is not OK
			System.out.println("Could not find COM port. Check the PORT_NAME constant");
		}

		try {
			// opens serial port, and uses class name for the appName.
			this.serialPort = (SerialPort) portId.open(this.getClass().getName(), TIME_OUT);

			// sets port parameters
			this.serialPort.setSerialPortParams(DATA_RATE, SerialPort.DATABITS_8, SerialPort.STOPBITS_1,
					SerialPort.PARITY_NONE);

			// adds event listeners
			this.serialPort.addEventListener(new MyListener(this.serialPort));
			this.serialPort.notifyOnDataAvailable(true);
		}
		catch (Exception e) {
			System.err.println(e.toString());
		}
	}

	/**
	 * This should be called when you stop using the port.
	 * This will prevent port locking on platforms like Linux.
	 */
	public synchronized void close() {
		if (this.serialPort != null) {
			this.serialPort.removeEventListener();
			this.serialPort.close();
			System.out.println("Closing the serial connection and the program");
		}
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception {
		// loads the jnilib
		Demo.loadJniLib();

		Demo demo = new Demo();
		// initializes the connection with arduino
		demo.initialize();
		System.out.println("Started");
		// type something in the console to close the program
		if (System.in.read() != -1) {
			demo.close();
		}
	}

	class MyListener implements SerialPortEventListener {

		/**
		 * The port to be listened
		 */
		private final SerialPort port;

		/**
		 * Constructor of the listener, it will listen the given {@link SerialPort}.
		 */
		public MyListener(SerialPort port) {
			super();
			this.port = port;
		}

		/*
		 * (non-Javadoc)
		 * 
		 * @see gnu.io.SerialPortEventListener#serialEvent(gnu.io.SerialPortEvent)
		 */
		public void serialEvent(SerialPortEvent event) {
			// if the event type is DATA_AVAILABLE it means the arduino sent data through the serial port
			if (event.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
				try {
					int available = this.port.getInputStream().available();
					byte chunk[] = new byte[available];
					this.port.getInputStream().read(chunk, 0, available);

					// Redirects the data to the standard output
					System.out.print(new String(chunk));

				}
				catch (IOException e) {
					// something went wrong while reading the data sent by the arduino
					System.err.println(e.toString());
				}
			}
		}
	}

}