public void addCollisionListener(RagdollCollisionListener listener) {
        if (listeners == null) {
            listeners = new ArrayList<RagdollCollisionListener>();
        }
        listeners.add(listener);
    }
Add a collision listener to this control.

@param listener (not null, alias created)
jme3-jbullet/src/main/java/com/jme3/bullet/control/KinematicRagdollControl.java