if (graphics.get(f) == null) graphics.remove(f); graphics.put(f, graphic);
synchronized (lock) { if (graphics.get(f) != null) throw new IllegalArgumentException("Error: "+graphic+" is already registered for frame "+f);  graphics.put(f, graphic);  }
    public void registerGraphic(org.cougaar.core.qos.frame.Frame f, ShapeGraphic graphic) {        if (f == null || graphic == null)            return;        //if (graphics.get(f) != null)        //  throw new IllegalArgumentException("Error: "+graphic+" is already registered for frame "+f);        if (graphics.get(f) == null)            graphics.remove(f);        graphics.put(f, graphic);    }