TrafficSim/app/src/main/java/de/hems/trafficsim/Track.java

package de.hems.trafficsim;

import java.util.ArrayList;
import java.util.List;
import java.util.Observable;

public class Track extends Observable {
    protected List<Vehicle> vehicles;
    protected float trackLength;

    public List<Vehicle> getVehicles() {
        return vehicles;
    }

    public float getTrackLength() {
        return trackLength;
    }

    public Track(int numberVehicles, float trackLength) {
        this.trackLength = trackLength;
        this.vehicles = createVehiclesList(numberVehicles);

    }

    protected List<Vehicle> createVehiclesList(int numberVehicles){
        List<Vehicle> result = new ArrayList<>();
        for(int i=0;i<numberVehicles;i++){
            Vehicle vehicle = new Vehicle(i, i, 5, 0.2f, this.trackLength);
            result.add(vehicle);
        }

        return result;
    }

    public void timeElapse(float timeStep) {
        for(int i=0; i<vehicles.size();i++) {
            Vehicle v = vehicles.get(i);
            int forerunnerIndex = i + 1;
            if (forerunnerIndex >= vehicles.size()) {
                forerunnerIndex -= vehicles.size();
            }
            Vehicle forerunner = vehicles.get(forerunnerIndex);
            float distanceForerunner = forerunner.getPosition() - v.getPosition() - 1;
            if(distanceForerunner < 0.0){
                distanceForerunner += this.trackLength;
            }
            v.updateVelocity(distanceForerunner);
        }

        for(Vehicle v: vehicles){
            v.timeElapse(50);
        }

        this.setChanged();
        this.notifyObservers(this);
        this.clearChanged();
    }
}