Main.java

/************************************************************************
 * ORGANIZATION  :  SavageHomeAutomation
 * PROJECT       :  Simple Components Sample using Pi4J & Raspberry Pi
 * FILENAME      :  Main.java
 * **********************************************************************
 *
 * Copyright (C) 2013 Robert Savage
 *
 * 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.
 */

import com.pi4j.component.light.LED;
import com.pi4j.component.light.LightListener;
import com.pi4j.component.light.LightStateChangeEvent;
import com.pi4j.component.light.impl.GpioLEDComponent;
import com.pi4j.component.switches.MomentarySwitch;
import com.pi4j.component.switches.SwitchListener;
import com.pi4j.component.switches.SwitchState;
import com.pi4j.component.switches.SwitchStateChangeEvent;
import com.pi4j.component.switches.impl.GpioMomentarySwitchComponent;
import com.pi4j.io.gpio.*;
import org.fusesource.jansi.Ansi;
import org.fusesource.jansi.AnsiConsole;

/**
 * This example code demonstrates how to create a simple Java program
 * to listen for button presses to control an LED using a Raspberry Pi
 * and the Pi4J Java library.  This example uses component interfaces
 * rather than direct GPIO access.
 *
 * @author Robert Savage
 */
public class Main {

    // create GPIO controller
    private static final GpioController gpio = GpioFactory.getInstance();


    public static void main(String args[]) throws InterruptedException {

        // init JANSI
        // (using jansi for color console output)
        AnsiConsole.systemInstall();

        // display welcome message
        AnsiConsole.out().println(Ansi.ansi().fg(Ansi.Color.CYAN).a(Ansi.Attribute.INTENSITY_BOLD)
            .a("-----------------------------------------------\n")
            .a("\n")
            .a("Welcome to JavaOne 2013 - [[ CON7968 ]]\n")
            .a("\n")
            .a("  Let's Get Physical: I/O Programming with\n")
            .a("  Java on the Raspberry Pi with Pi4J\n")
            .a("\n")
            .a("-----------------------------------------------\n")
            .a("<--Pi4J--> Components Example ... started.\n")
            .a("-----------------------------------------------\n").reset());


        // ******************************************************************
        // INITIALIZE
        // ******************************************************************

        // momentary push-button switch; activates when button is pushed
        final MomentarySwitch momentarySwitch = new GpioMomentarySwitchComponent(
                gpio.provisionDigitalInputPin(RaspiPin.GPIO_06, PinPullResistance.PULL_UP),
                PinState.HIGH,   // "OFF" PIN STATE
                PinState.LOW);   // "ON" PIN STATE

        // led; illuminates when momentary switch is pushed
        final GpioPinDigitalOutput ledPin = gpio.provisionDigitalOutputPin(RaspiPin.GPIO_07, PinState.LOW);
        final LED led  = new GpioLEDComponent(ledPin);

        // make sure the LED is turned off when program shuts down
        gpio.setShutdownOptions(true, PinState.LOW, ledPin);

        // ******************************************************************
        // BUTTON EVENT LISTENER
        // ******************************************************************

        // create momentary switch event listener
        momentarySwitch.addListener(new SwitchListener() {
            @Override
            public void onStateChange(SwitchStateChangeEvent event) {
                // display console message
                AnsiConsole.out().println(Ansi.ansi().fg(Ansi.Color.WHITE)
                        .a("Momentary switch pressed: state = " + event.getNewState()).reset());

                if(event.getNewState() == SwitchState.ON){
                    led.on();    // turn ON LED
                }
                else{
                    led.off();  // turn OFF LED
                }
            }
        });

        // create LED light listener just to echo out the new LED state
        led.addListener(new LightListener() {
            @Override
            public void onStateChange(LightStateChangeEvent event) {
                // display console message
                if(event.isOn()){
                    AnsiConsole.out().println(Ansi.ansi().fg(Ansi.Color.GREEN).a("LED is ON").reset());
                }
                else{
                    AnsiConsole.out().println(Ansi.ansi().fg(Ansi.Color.RED).a("LED is OFF").reset());
                }
            }
        });

        // ******************************************************************
        // PROGRAM TERMINATION
        // ******************************************************************

        // wait for user input to terminate program
        AnsiConsole.out().println(Ansi.ansi()
                .fg(Ansi.Color.BLACK)
                .bg(Ansi.Color.CYAN)
                .a("PRESS [ENTER] TO EXIT")
                .reset());
        System.console().readLine();

        // shutdown GPIO controller
        gpio.shutdown();
    }
}