small changes

src/Worm.java

@@ -13,7 +13,6 @@ public class Worm {
     private double minRadius;
     // mass
     private double mass;
-    private final int rho = 1062;
 
     // points
     private int points;
@@ -104,6 +103,9 @@ public class Worm {
     }
 
     public void setRadius(double radius) {
+        if (radius < this.minRadius) {
+            throw new IllegalArgumentException();
+        }
         this.radius = radius;
         setMass(radius);
     }
@@ -122,7 +124,8 @@ public class Worm {
 
     private void setMass(double radius) {
 
-        double mass = this.rho * (4 / 3 * Math.PI * Math.pow(radius, 3));
+        final int rho = 1062;
+        double mass = rho * (4 / 3 * Math.PI * Math.pow(radius, 3));
 
         this.mass = mass;
         setMaxPoints(mass);
@@ -133,6 +136,11 @@ public class Worm {
     }
 
     public void setPoints(int points) {
+        if (points > this.maxPoints) {
+            points = this.maxPoints;
+        }
+        else if (points < 0)
+            points = 0;
         this.points = points;
     }
 
@@ -141,5 +149,6 @@ public class Worm {
     }
     private void setMaxPoints(double maxPoints) {
         this.maxPoints = (int) Math.round(maxPoints);
+        setPoints(this.points);
     }
 }