Constructors

class RotationBehavior extends Behavior {
    TransformGroup objectTransform;
    WakeupOnElapsedFrames w;

    Matrix4d rotMat = new Matrix4d();
    Matrix4d objectMat = new Matrix4d();
    Transform3D t = new Transform3D();

    // Override Behavior's initialize method to set up wakeup
    // criteria

    public void initialize() {
        // Establish initial wakeup criteria

        wakeupOn(w);
   }

    // Override Behavior's stimulus method to handle the event

    public void processStimulus(Enumeration criteria) {
        // Rotate by another PI/120.0 radians

        objectMat.mul(objectMat, rotMat);
        t.set(objectMat);
        objectTransform.setTransform(t);

        // Set wakeup criteria for next time

        wakeupOn(w);
    }

    // Constructor for rotation behavior.

    public RotationBehavior(TransformGroup tg, int numFrames) {
        w = new WakeupOnElapsedFrames(numFrames);
        objectTransform = tg;
        objectMat.setIdentity();

        // Create a rotation matrix that rotates PI/120.0
        // radians per frame
        rotMat.rotX(Math.PI/120.0);

        // Note: When this object is duplicated via cloneTree,
        // the cloned RotationBehavior node needs to point to
        // the TransformGroup in the just-cloned tree.    
    }

    // Sets a new TransformGroup.

    public void setTransformGroup(TransformGroup tg) {
        objectTransform = tg;
    }

    // The next two methods are needed for cloneTree to operate
    // correctly.
    // cloneNode is needed to provide a new instance of the user
    // derived subclass.

    public Node cloneNode(boolean forceDuplicate) {
        // Get all data from current node needed for
        // the constructor
        int numFrames = w.getElapsedFrameCount();

        RotationBehavior r =
            new RotationBehavior(objectTransform, numFrames);
        r.duplicateNode(this, forceDuplicate);
        return r;
    }
    // duplicateNode is needed to duplicate all super class
    // data as well as all user data.

    public void duplicateNode(Node originalNode, boolean 
     forceDuplicate) {
        super.duplicateNode(originalNode, forceDuplicate);
        // Nothing to do here - all unique data was handled
        // in the constructor in the cloneNode routine.
    }

    // duplicateNode is needed to duplicate all super class
    // data as well as all user data.

    public void duplicateNode(Node originalNode, boolean 
     forceDuplicate) {
        super.duplicateNode(originalNode, forceDuplicate);
        // Nothing to do here - all unique data was handled
        // in the constructor in the cloneNode routine.

    }

    // Callback for when this leaf is cloned. For this object
    // we want to find the cloned TransformGroup node that this
    // clone Leaf node should reference.

    public void updateNodeReferences(NodeReferenceTable t) {
        super.updateNodeReferences(t);

        // Update node's TransformGroup to proper reference

        TransformGroup newTg =
         (TransformGroup)t.getNewObjectReference(
            objectTransform);
        setTransformGroup(newTg);
    }
}