code: public Perspective getCurrentPerspective(){
  		String key = MessageFormat.format(CURRENT_PERSPECTIVE_KEY, new Object[]{pageName});
  		String id = prefs.get(key, DEFAULT_PERSPECTIVE_KEY);
  		Iterator it = perspectives.iterator();
  		while(it.hasNext()){
  			Perspective perspective = (Perspective)it.next();
  			if(id.equals(perspective.getId())){
  				return perspective;
  			}
  		}
  		return NullPerspective.NULL_PERSPECTIVE;
  	}
docs: Returns the current perspective, or the NullPerspective instance if
  no current perspective is defined.