code: //==============================================================================
  //	
  //	Copyright (c) 2002-
  //	Authors:
  //	* Dave Parker <d.a.parker@cs.bham.ac.uk> (University of Birmingham/Oxford)
  //	* Aistis Simaitis <aistis.aimaitis@cs.ox.ac.uk> (University of Oxford)
  //	
  //------------------------------------------------------------------------------
  //	
  //	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 strat;
  
  import prism.PrismLog;
  
  /**
   * Interface for classes to store strategies (for MDPs, games, etc.)
   */
  public interface Strategy
  {
  	// Types of info stored for each choice
  	public enum Choice {
  		INDEX, ACTION, UNKNOWN, ARBITRARY, UNREACHABLE;
  	};
  	
  	/**
  	 * Export the strategy to a PrismLog, displaying strategy choices as action names.
  	 */
  	public void exportActions(PrismLog out);
  	
  	/**
  	 * Export the strategy to a PrismLog, displaying strategy choices as indices.
  	 */
  	public void exportIndices(PrismLog out);
  	
  	/**
  	 * Export the model induced by this strategy to a PrismLog.
  	 */
  	public void exportInducedModel(PrismLog out);
  	
  	/**
  	 * Export the strategy to a dot file (of the model showing the strategy).
  	 */
  	public void exportDotFile(PrismLog out);
  	
  	/**
  	 * Initialise the strategy, based on an initial model state.
  	 * @param s Initial state of the model
  	 */
  	public void initialise(int s);
  
  	/**
  	 * Update the strategy, based on the next step in a model's history.
  	 * @param action The action taken in the previous state of the model
  	 * @param s The new state of the model
  	 */
  	public void update(Object action, int s);
  	
  	/**
  	 * Get the action chosen by the strategy in the current state (assuming it is deterministic). 
  	 */
  	public Object getChoiceAction();
  	
  	/**
  	 * Clear storage of the strategy.
  	 */
  	public void clear();
  }
  