code: //==============================================================================
  //	
  //	Copyright (c) 2016-
  //	Authors:
  //	* Joachim Klein <klein@tcs.inf.tu-dresden.de> (TU Dresden)
  //	
  //------------------------------------------------------------------------------
  //	
  //	This file is part of PRISM.
  //	
  //	PRISM is free software; you can redistribute it and/or modify
  //	it under the terms of the GNU General Public License as published by
  //	the Free Software Foundation; either version 2 of the License, or
  //	(at your option) any later version.
  //	
  //	PRISM is distributed in the hope that it will be useful,
  //	but WITHOUT ANY WARRANTY; without even the implied warranty of
  //	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  //	GNU General Public License for more details.
  //	
  //	You should have received a copy of the GNU General Public License
  //	along with PRISM; if not, write to the Free Software Foundation,
  //	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  //	
  //==============================================================================
  
  package explicit.graphviz;
  
  import java.util.BitSet;
  
  /**
   * A Decorator is called from the DOT output routines and
   * can modify the decoration that is attached at the
   * given node or edge in the GraphViz file.
   * <br>
   * Default implementations are provided that simply pass
   * through the decoration given as input, without any modification.
   */
  public interface Decorator
  {
  	/**
  	 * Called to allow modification of the decoration
  	 * attached to a state.
  	 * @param state the state index in the model
  	 * @param d the current decoration
  	 * @return an updated decoration (may return {@code d} and modify it)
  	 */
  	default Decoration decorateState(int state, Decoration d)
  	{
  		return d;
  	}
  
  	/**
  	 * Called to allow modification of the decoration
  	 * attached to non-deterministic transition choice.
  	 * @param from the state index in the model of the originating state
  	 * @param choice the choice index
  	 * @param d the current decoration
  	 * @return an updated decoration (may return {@code d} and modify it)
  	 */
  	default Decoration decorateTransition(int from, int choice, Decoration d)
  	{
  		return d;
  	}
  
  	/**
  	 * Called to allow modification of the decoration
  	 * attached to a probabilistic transition for a non-deterministic choice.
  	 * @param from the state index in the model of the originating state
  	 * @param to the state index in the model of the target state
  	 * @param choice the choice index
  	 * @param probability the probability (e.g., a Double, param.BigRational, param.Function)
  	 * @param d the current decoration
  	 * @return an updated decoration (may return {@code d} and modify it)
  	 */
  	default Decoration decorateProbability(int from, int to, int choice, Object probability, Decoration d)
  	{
  		return d;
  	}
  
  	/**
  	 * Called to allow modification of the decoration
  	 * attached to a probabilistic transition in a model without non-deterministic choices (e.g., DTMC, CTMC).
  	 * @param from the state index in the model of the originating state
  	 * @param to the state index in the model of the target state
  	 * @param probability the probability (e.g., a Double, param.BigRational, param.Function)
  	 * @param d the current decoration
  	 * @return an updated decoration (may return {@code d} and modify it)
  	 */
  	default Decoration decorateProbability(int from, int to, Object probability, Decoration d)
  	{
  		return d;
  	}
  
  	/**
  	 * Called to allow modification of the decoration
  	 * attached to an automaton edge.
  	 * @param from the state index in the automaton of the originating state
  	 * @param to the state index in the automaton of the target state
  	 * @param apElement a BitSet representing the current element of the alphabet (2^AP)
  	 * @param d the current decoration
  	 * @return an updated decoration (may return {@code d} and modify it)
  	 */
  	default Decoration decorateAutomatonEdge(int from, int to, BitSet apElement, Decoration d)
  	{
  		return d;
  	}
  
  }
  