RPI3TriggerGPIO.java

import java.util.concurrent.Callable;

import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinDigitalInput;
import com.pi4j.io.gpio.GpioPinDigitalOutput;
import com.pi4j.io.gpio.PinPullResistance;
import com.pi4j.io.gpio.PinState;
import com.pi4j.io.gpio.RaspiPin;
import com.pi4j.io.gpio.trigger.GpioCallbackTrigger;
import com.pi4j.io.gpio.trigger.GpioPulseStateTrigger;
import com.pi4j.io.gpio.trigger.GpioSetStateTrigger;
import com.pi4j.io.gpio.trigger.GpioSyncStateTrigger;
import java.util.HashMap;
import java.util.Map;
import com.pi4j.io.gpio.Pin;

/**
 * This example code demonstrates how to setup simple triggers for GPIO pins on the Raspberry Pi.
 *
 * @author Robert Savage
 */
public class TriggerGpioExamplePablo {

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

	// in-out mapping
	Map<Pin, Pin> map = new HashMap<Pin, Pin>();
        map.put(RaspiPin.GPIO_02, RaspiPin.GPIO_03);
        // TODO: more mappings


        System.out.println("<--Pi4J--> GPIO Trigger ... started.");

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

	// TODO: loop over the map, create all the pins in the keys, store those pins in a map

        // provision gpio pin #02 as an input pin with its internal pull down resistor enabled
        final GpioPinDigitalInput in1 = gpio.provisionDigitalInputPin(RaspiPin.GPIO_02,
                                                  PinPullResistance.PULL_DOWN);

        System.out.println(" ... complete the GPIO #02 circuit and see the triggers take effect.");


/* TODO: create each ping for the values in the map
        // setup gpio pins #04, #05, #06 as an output pins and make sure they are all LOW at startup
        GpioPinDigitalOutput myLed[] = {
            gpio.provisionDigitalOutputPin(RaspiPin.GPIO_04, "LED #1", PinState.LOW),
            gpio.provisionDigitalOutputPin(RaspiPin.GPIO_05, "LED #2", PinState.LOW),
            gpio.provisionDigitalOutputPin(RaspiPin.GPIO_06, "LED #3", PinState.LOW)
          };
*/
        GpioPinDigitalOutput out1 = gpio.provisionDigitalOutputPin(map.get(RaspiPin.GPIO_02), "LED #1", PinState.LOW);

        // create a gpio callback trigger on gpio pin#4; when #4 changes state, perform a callback
        // invocation on the user defined 'Callable' class instance

// only triggers when the sensor is HIGH, if no state is specified the trigger is fired
// on high and low state changes.

        in1.addTrigger(new GpioCallbackTrigger(PinState.HIGH, new Callable<Void>() {
            @Override
            public Void call() throws Exception {
                System.out.println(" --> GPIO TRIGGER CALLBACK RECEIVED ");

                out1.toggle();

                return null;
            }
        }));

        // keep program running until user aborts (CTRL-C)
        while (true) {
            Thread.sleep(200);
        }

        // stop all GPIO activity/threads by shutting down the GPIO controller
        // (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks)
        // gpio.shutdown();   <--- implement this method call if you wish to terminate the Pi4J GPIO controller
    }
}