implement traffic algorithms

app/src/main/java/de/hems/trafficsim/MainActivity.java

@@ -17,7 +17,7 @@ public class MainActivity extends AppCompatActivity implements Observer {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
-        this.track = new Track();
+        this.track = new Track(20);
         this.track.addObserver(this);
 
     }
@@ -26,14 +26,20 @@ public class MainActivity extends AppCompatActivity implements Observer {
     public void update(Observable observable, Object o) {
         String s = "";
         for (Vehicle v: this.track.getVehicles()){
-            s+="Pos = " + v.getPosition() +"\n";
+            s+= "Vehicle " + v.id + "   |   "
+                    + "Pos = " + v.getPosition() + "   |   "
+                    + "Vel = " + v.getCurVelocity()+ "   |   "
+                    + "\n";
+            ;
         }
         TextView view = (TextView) findViewById(R.id.debugTextView);
         view.setText(s);
         view.invalidate();
     }
 
-    public void onStepButtonClick (View view){
+    public void onStepButtonClick (View view) {
+        for (int j = 0; j < 3000; j++) {
             this.track.timeElapse(50);
         }
+    }
 }

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

@@ -6,26 +6,46 @@ import java.util.Observable;
 
 public class Track extends Observable {
     protected List<Vehicle> vehicles;
+
+
     public List<Vehicle> getVehicles() {
+
         return vehicles;
     }
 
-
+    public Track(int numberVehicles) {
-
+        this.vehicles = createVehiclesList(numberVehicles);
-    public Track() {
-        this.vehicles = createVehiclesList();
     }
 
-    protected List<Vehicle> createVehiclesList(){
+    protected List<Vehicle> createVehiclesList(int numberVehicles){
         List<Vehicle> result = new ArrayList<>();
-        for(int i=0;i<10;i++){
+        for(int i=0;i<numberVehicles;i++){
-            Vehicle vehicle = new Vehicle(i, 5, 0.2f);
+            Vehicle vehicle = new Vehicle(i, i, 5, 0.2f);
             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 += 50;
+            }
+            v.updateVelocity(distanceForerunner);
+        }
+
+        for(Vehicle v: vehicles){
+            v.timeElapse(50);
+        }
+
         this.setChanged();
         this.notifyObservers(this);
         this.clearChanged();

app/src/main/java/de/hems/trafficsim/Vehicle.java

@@ -1,16 +1,24 @@
 package de.hems.trafficsim;
 
+import java.util.Random;
+
 public class Vehicle {
+    protected int id;
     protected float position;
     protected float curVelocity;
     protected float maxVelocity;
+    protected float brakeProp;
+
+
+    public Vehicle(int id, int position, float maxVelocity, float brakeProp) {
+        this.id = id;
+        this.position = position;
+        this.maxVelocity = maxVelocity;
+        this.brakeProp = brakeProp;
+        this.curVelocity = 0;
 
-    public void setForerunner(Vehicle forerunner) {
-        this.forerunner = forerunner;
     }
 
-    protected Vehicle forerunner;
-
     public float getPosition() {
         return position;
     }
@@ -19,17 +27,26 @@ public class Vehicle {
         return curVelocity;
     }
 
-    protected float brakeProp;
+    public void updateVelocity(float distanceForerunner) {
+        Random random = new Random();
+
+        float r = random.nextFloat();
+
+        if (curVelocity < maxVelocity) {
+            curVelocity = curVelocity + 1;
+        }
+        if (r < brakeProp && curVelocity > 0) {
+            curVelocity = getCurVelocity() - 1;
+        }
+        if (curVelocity > distanceForerunner) {
+            curVelocity = distanceForerunner;
+        }
 
-    public Vehicle(float position, float maxVelocity, float brakeProp) {
-        this.position = position;
-        this.maxVelocity = maxVelocity;
-        this.brakeProp = brakeProp;
-        this.curVelocity = 0;
-        this.forerunner = null;
     }
 
     public void timeElapse(float timeStep) {
-
+        position = (position + curVelocity) % 50;
     }
+
 }
+