Finish AB4

src/HierarchicalSystem.java

@@ -1,16 +1,113 @@
+import codedraw.CodeDraw;
+
 /**
  * A cosmic system that is composed of a central named body (of type 'NamedBodyForcePair')
  * and an arbitrary number of subsystems (of type 'CosmicSystem') in its orbit.
  * This class implements 'CosmicSystem'.
  */
-public class HierarchicalSystem /* TODO: add clause */ {
+public class HierarchicalSystem implements CosmicSystem {
 
-    // TODO: define missing parts of this class.
+    private final NamedBodyForcePair central;
+    private final CosmicSystem[] orbit;
+    private final CosmicSystem[] all;
 
     /**
      * Initializes this system with a name and a central body.
      */
     public HierarchicalSystem(NamedBodyForcePair central, CosmicSystem... inOrbit) {
-        // TODO: implement constructor.
+        this.central = central;
+        this.orbit = inOrbit;
+        this.all = new CosmicSystem[this.orbit.length + 1];
+        this.all[0] = central;
+        System.arraycopy(this.orbit, 0, this.all, 1, this.orbit.length);
+    }
+
+    @Override
+    public Vector3 getMassCenter() {
+        double mass = this.getMass();
+        Vector3 massCenter = new Vector3();
+        for (CosmicSystem sys : all) {
+            massCenter.add(sys.getMassCenter().times(sys.getMass() / mass));
+        }
+        return massCenter;
+    }
+
+    @Override
+    public double getMass() {
+        double mass = 0;
+        for (CosmicSystem sys : all) {
+            mass += sys.getMass();
+        }
+        return mass;
+    }
+
+    @Override
+    public int numberOfBodies() {
+        int num = 0;
+        for (CosmicSystem sys : all) {
+            num += sys.numberOfBodies();
+        }
+        return num;
+    }
+
+    @Override
+    public double distanceTo(CosmicSystem cs) {
+        return this.getMassCenter().distanceTo(cs.getMassCenter());
+    }
+
+    @Override
+    public void addForceFrom(Body b) {
+        for (CosmicSystem sys : all) {
+            sys.addForceFrom(b);
+        }
+    }
+
+    @Override
+    public void addForceTo(CosmicSystem cs) {
+        for (CosmicSystem sys : all) {
+            sys.addForceTo(cs);
+        }
+    }
+
+    @Override
+    public BodyLinkedList getBodies() {
+        BodyLinkedList list = new BodyLinkedList();
+        for (CosmicSystem sys : all) {
+            for (Body b : sys.getBodies()) {
+                list.addFirst(b);
+            }
+        }
+        return list;
+    }
+
+    @Override
+    public void update() {
+        for (CosmicSystem sys : all) {
+            sys.update();
+        }
+    }
+
+    @Override
+    public void draw(CodeDraw cd) {
+        for (CosmicSystem sys : all) {
+            sys.draw(cd);
+        }
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(central.getName());
+
+        sb.append(" {");
+        boolean first = true;
+        for (CosmicSystem sys : orbit) {
+            if (!first) sb.append(", ");
+            sb.append(sys.toString());
+            first = false;
+        }
+        sb.append("}");
+
+        return sb.toString();
     }
 }