[TASK] Begin implementing a car rental service.

src/main/java/lu/jpt/csparqltest/Main.java

@@ -6,12 +6,11 @@ import org.apache.log4j.PropertyConfigurator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import eu.larkc.csparql.cep.api.RdfStream;
 import eu.larkc.csparql.core.engine.ConsoleFormatter;
 import eu.larkc.csparql.core.engine.CsparqlEngine;
 import eu.larkc.csparql.core.engine.CsparqlEngineImpl;
 import eu.larkc.csparql.core.engine.CsparqlQueryResultProxy;
-import lu.jpt.csparqltest.carexample.CarStreamGenerator;
+import lu.jpt.csparqltest.rentacar.RentACarSimulation;
 
 public class Main {
 
@@ -37,15 +36,16 @@ public class Main {
 		//logger.debug("Engine from: " + engine.getClass().getProtectionDomain().getCodeSource());
 		
 		// Create and register stream generator at specific URI
-		RdfStream carStreamGenerator = new CarStreamGenerator("http://myexample.org/cars");
+		RentACarSimulation simulation = new RentACarSimulation();
-		engine.registerStream(carStreamGenerator);
+		engine.registerStream(simulation.getCarStream());
+		engine.registerStream(simulation.getDriverStream());
 		
-		// Run stream generator
+		// Run simulation that is feeding the streams
-		final Thread t = new Thread((Runnable) carStreamGenerator);
+		Thread simulationThread = new Thread(simulation);
-		t.start();
+		simulationThread.start();
 
 		// Now build a query to run - interchangeable
-		String query = Main.getBreakingDownCarsQuery();
+		String query = Main.getSPO();
 		
 		// Create a result proxy by registering the query at the engine
 		CsparqlQueryResultProxy resultProxy = null;
@@ -68,14 +68,29 @@ public class Main {
 		// Unregister the resultProxy (and thus the query) from the engine
 		engine.unregisterQuery(resultProxy.getId());
 		
-		// Softly stop the stream generator and unregister it from the engine
+		// Softly stop the simulation and unregister its streams
-		((CarStreamGenerator) carStreamGenerator).pleaseStop();
+		simulation.pleaseStopSimulation();
-		engine.unregisterStream(carStreamGenerator.getIRI());
+		simulationThread.interrupt();
+		engine.unregisterStream(simulation.getCarStream().getIRI());
+		engine.unregisterStream(simulation.getDriverStream().getIRI());
 
 		// That's it!
 		System.exit(0);
 	}
 	
+	private static String getSPO() {
+		return "REGISTER QUERY BasicCarInfo AS "
+				+ "PREFIX f: <http://larkc.eu/csparql/sparql/jena/ext#> "
+				+ "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> "
+				+ "PREFIX car: <http://myexample.org/car#> "
+				+ "SELECT ?s ?p ?o "
+				+ "FROM STREAM <http://myexample.org/car> [RANGE 5s STEP 1s] "
+				+ "FROM STREAM <http://myexample.org/driver> [RANGE 5s STEP 1s] "
+				+ "WHERE { "
+				+ " ?s ?p ?o . "
+				+ "}";
+	}
+	
 	private static String getBasicCarInfoQuery() {
 		return "REGISTER QUERY BasicCarInfo AS "
 				+ "PREFIX f: <http://larkc.eu/csparql/sparql/jena/ext#> "

src/main/java/lu/jpt/csparqltest/rentacar/Car.java

@@ -0,0 +1,111 @@
+package lu.jpt.csparqltest.rentacar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import eu.larkc.csparql.cep.api.RdfQuadruple;
+import lu.jpt.csparqltest.util.RandomHelper;
+
+public class Car {
+	// Fix knowledge about the available car types:
+	private static final String[] CAR_TYPENAME = {"A", "B", "C"};
+	private static final int[] MIN_RPM = {2000, 800, 1400};
+	private static final int[] MAX_RPM = {4300, 1900, 2500};
+	private static final double[] MIN_TIRE_PRESSURE = {2.9, 3.5, 2.6};
+	private static final double[] MAX_TIRE_PRESSURE = {3.2, 3.8, 3.0};
+	// Sitzplätze? Reservierungen für X Personen?
+
+	private int id;
+	private final String IRI;
+	
+	private List<RdfQuadruple> quads;
+	
+	// Car-specific attributes
+	private final int CAR_TYPE;
+	
+	private boolean motorOn;
+	private int motorRpm;
+	private int motorMinRpm;
+	private int motorMaxRpm;
+	private int speed;
+	private double tirePressure;
+
+
+	public Car(int id, String baseIri) {
+		this.id = id;
+		this.IRI = baseIri;
+		this.quads = new ArrayList<RdfQuadruple>();
+		this.CAR_TYPE = RandomHelper.nextInt(2);
+		this.initializeCarType(this.CAR_TYPE);
+	}
+		
+	private void initializeCarType(int carType) {
+		this.motorOn = false;
+		this.motorRpm = 0;
+		this.motorMinRpm = Car.MAX_RPM[carType];
+		this.motorMaxRpm = Car.MAX_RPM[carType];
+		this.speed = 0;
+		this.tirePressure = (Car.MIN_TIRE_PRESSURE[carType] + Car.MAX_TIRE_PRESSURE[carType]) / 2.0;
+	}
+
+	public void turnOn() {
+		
+	}
+	
+	public void turnOff() {
+		
+	}
+	
+	public void setHandBrake(boolean on) {
+		
+	}
+	
+	public void accelerate() {
+		
+	}
+	
+	public void slowDown() {
+		
+	}
+	
+	public void crash() {
+		
+	}
+	
+	public void load() {
+		
+	}
+	
+	public void unload() {
+		
+	}
+	
+	/**
+	 * Update internal stuff according to state
+	 */
+	public void tick() {
+		
+	}
+	
+	public int getID() {
+		return this.id;
+	}
+	
+	public String getIri() {
+		return this.IRI + "#" + this.id;
+	}
+
+	public List<RdfQuadruple> getQuadruples() {
+		List<RdfQuadruple> result = this.quads;
+		this.quads = new ArrayList<RdfQuadruple>();
+		return result;
+	}
+	
+	public String toString() {
+		StringBuilder sb = new StringBuilder("[#");
+		sb.append(this.id);
+		sb.append("]");
+		return sb.toString();
+	}
+	
+}

src/main/java/lu/jpt/csparqltest/rentacar/CarPool.java

@@ -0,0 +1,50 @@
+package lu.jpt.csparqltest.rentacar;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class CarPool {
+	
+	private List<Car> cars;
+	private List<Car> availableCars;
+	private Random rand;
+	
+	public CarPool(int numberOfCars, String carIri) {
+		this.rand = new Random();
+		this.cars = new ArrayList<Car>();
+		this.availableCars = new ArrayList<Car>();
+		for(int i = 0; i < numberOfCars; i++) {
+			Car newCar = new Car(i, carIri);
+			this.cars.add(newCar);
+			this.availableCars.add(newCar);
+		}
+	}
+	
+	/**
+	 * Fetch a random car from the car pool
+	 * @return Car the random car
+	 */
+	public Car takeRandomCar() {
+		Car randomCar = this.availableCars.get(this.rand.nextInt(this.availableCars.size()));
+		this.availableCars.remove(randomCar);
+		return randomCar;
+	}
+	
+	/**
+	 * Return the car back into the car pool
+	 * @param returnedCar The returned car
+	 */
+	public void returnCar(Car returnedCar) {
+		this.availableCars.add(returnedCar);
+	}
+	
+	/**
+	 * Return a copy of the list of cars for simulation purposes.
+	 * @return List<Car> List of cars in the CarPool
+	 */
+	public List<Car> getCars() {
+		return new ArrayList<Car>(this.cars);
+	}
+	
+}

src/main/java/lu/jpt/csparqltest/rentacar/Driver.java

@@ -0,0 +1,89 @@
+package lu.jpt.csparqltest.rentacar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import eu.larkc.csparql.cep.api.RdfQuadruple;
+import lu.jpt.csparqltest.util.RandomHelper;
+
+public class Driver {
+	
+	private int id;
+	private final String IRI;
+	private CarPool carPool;
+	
+	private int carUseCycles;
+	private Car car;
+	
+	private List<RdfQuadruple> quads;
+	
+	public Driver(int id, CarPool carPool, String baseIri) {
+		this.id = id;
+		this.carPool = carPool;
+		this.IRI = baseIri;
+		this.car = null;
+		this.quads = new ArrayList<RdfQuadruple>();
+		// Pick a random behaviour and stick to it.
+	}
+	
+	public int getID() {
+		return this.id;
+	}
+	
+	public String getIri() {
+		return this.IRI + "#" + this.id;
+	}	
+
+	/**
+	 * Simulation triggers this from the outside to make the driver do something
+	 * given a car is available.
+	 */
+	public void tick() {
+		if(car == null) {
+			// Nothing to do, maybe randomly take a car
+			if(RandomHelper.isLuckyByChance(0.4)) {
+				this.assignCar(this.carPool.takeRandomCar(), RandomHelper.getRandomNumberWithin(5,20));
+			}
+		} else {
+			// Do random things with the car
+			this.useCar(this.car);
+			// Decrement use cycles
+			this.carUseCycles--;
+			if(this.carUseCycles == 0) {
+				this.returnCar();
+			}
+		}
+	}
+
+	public void assignCar(Car car, int useCycles) {
+		this.car = car;
+		this.carUseCycles = useCycles;
+		this.quads.add(new RdfQuadruple(this.getIri(), this.IRI+"#took", this.car.getIri(), System.currentTimeMillis()));
+		this.quads.add(new RdfQuadruple(this.getIri(), this.IRI+"#usagePeriod", useCycles+"^^http://www.w3.org/2001/XMLSchema#integer", System.currentTimeMillis()));
+	}
+	
+	private void useCar(Car car) {
+		// Whatever, hit the gas, slam the breaks, drift around, drive casually
+		
+	}
+	
+	private void returnCar() {
+		this.quads.add(new RdfQuadruple(this.getIri(), this.IRI+"#returned", this.car.getIri(), System.currentTimeMillis()));
+		this.car = null;
+	}
+
+	public List<RdfQuadruple> getQuadruples() {
+		List<RdfQuadruple> result = this.quads;
+		this.quads = new ArrayList<RdfQuadruple>();
+		return result;
+	}
+	
+	public String toString() {
+		StringBuilder sb = new StringBuilder("[#");
+		sb.append(this.id);
+		sb.append("]");
+		return sb.toString();
+	}
+	
+	
+}

src/main/java/lu/jpt/csparqltest/rentacar/RentACarSimulation.java

@@ -0,0 +1,98 @@
+package lu.jpt.csparqltest.rentacar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import eu.larkc.csparql.cep.api.RdfQuadruple;
+import eu.larkc.csparql.cep.api.RdfStream;
+
+public class RentACarSimulation implements Runnable {
+
+	public static final String BASE_IRI = "http://myexample.org";
+	public static final String CAR_IRI = BASE_IRI + "/car";
+	public static final String DRIVER_IRI = BASE_IRI + "/driver";
+	
+	private CarPool carPool;
+	private List<Driver> drivers;
+	
+	private volatile boolean runSimulation;
+	
+	private RdfStream carStream;
+	private RdfStream driverStream;
+	
+	
+	public RentACarSimulation() {
+		int numberOfCars = 6;
+		int numberOfCustomers = 1;
+		// Create a car pool and drivers
+		this.carPool = new CarPool(numberOfCars, CAR_IRI);
+		this.drivers = new ArrayList<Driver>();
+		for(int i = 0; i < numberOfCustomers; i++) {
+			this.drivers.add(new Driver(i, this.carPool, DRIVER_IRI));
+		}
+		// Create streams
+		this.carStream = new RdfStream(CAR_IRI);
+		this.driverStream = new RdfStream(DRIVER_IRI);
+		// Green light for simulation
+		this.runSimulation = true;
+	}
+	
+	public RdfStream getCarStream() {
+		return this.carStream;
+	}
+	
+	public RdfStream getDriverStream() {
+		return this.driverStream;
+	}
+
+	/**
+	 * All the simulation is happening within its own Thread
+	 */
+	@Override
+	public void run() {
+		// Run the simulation as long as needed
+		while(this.runSimulation) {
+			// A driver will autonomously pick a car, use it for some time and leave it.
+			for(Driver driver : this.drivers) {
+				driver.tick();
+			}
+			for(Car car: this.carPool.getCars()) {
+				car.tick();
+			}
+			// Push the new data into the stream(s)
+			this.pushDataToStream();
+			// Now wait a short while
+			try {
+				Thread.sleep(1000);
+			} catch (InterruptedException e) {
+				// We got interrupted, so what.
+			}
+		}
+	}
+	
+	/**
+	 * Push all the data into the corresponding streams for processing.
+	 */
+	private void pushDataToStream() {
+		for(Driver d : this.drivers) {
+			List<RdfQuadruple> quads = d.getQuadruples();
+			for(RdfQuadruple q : quads) {
+				this.driverStream.put(q);
+			}
+		}
+		for(Car c : this.carPool.getCars()) {
+			List<RdfQuadruple> quads = c.getQuadruples();
+			for(RdfQuadruple q : quads) {
+				this.carStream.put(q);
+			}
+		}
+	}
+
+	/**
+	 * Tells the simulation to stop
+	 */
+	public void pleaseStopSimulation() {
+		this.runSimulation = false;
+	}
+
+}

src/main/java/lu/jpt/csparqltest/util/RandomHelper.java

@@ -0,0 +1,24 @@
+package lu.jpt.csparqltest.util;
+
+import java.util.Random;
+
+public class RandomHelper {
+
+	private static Random myRandom = new Random();
+	
+	
+	private RandomHelper() {}
+	
+	public static int nextInt(int bound) {
+		return RandomHelper.myRandom.nextInt(bound);
+	}
+	
+	public static int getRandomNumberWithin(int min, int max) {
+		return min + RandomHelper.myRandom.nextInt((max + 1) - min);
+	}
+	
+	public static boolean isLuckyByChance(double chance) {
+		return RandomHelper.myRandom.nextDouble() < chance;
+	}
+	
+}