code: //==============================================================================
  //	
  //	Copyright (c) 2002-
  //	Authors:
  //	* Dave Parker <d.a.parker@cs.bham.ac.uk> (University of Birmingham/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 explicit;
  
  import java.util.BitSet;
  import java.util.List;
  
  import prism.PrismComponent;
  import prism.PrismException;
  
  /**
   * Abstract class for (explicit) classes that compute (M)ECs, i.e. (maximal) end components,
   * for a nondeterministic model such as an MDP.
   */
  public abstract class ECComputer extends PrismComponent
  {
  	/**
  	 * Static method to create a new ECComputer object, depending on current settings.
  	 */
  	public static ECComputer createECComputer(PrismComponent parent, NondetModel model) throws PrismException
  	{
  		// Only one algorithm implemented currently
  		return new ECComputerDefault(parent, model);
  	}
  
  	/**
  	 * Base constructor.
  	 */
  	public ECComputer(PrismComponent parent) throws PrismException
  	{
  		super(parent);
  	}
  
  	/**
  	 * Compute states of maximal end components (MECs) and store them.
  	 * They can be retrieved using {@link #getMECStates()}.
  	 */
  	public abstract void computeMECStates() throws PrismException;
  
  	/**
  	 * Compute states of all maximal end components (MECs) in the submodel obtained
  	 * by restricting this one to the set of states {@code restrict}, and store them.
  	 * They can be retrieved using {@link #getMECStates()}.
  	 * If {@code restrict} is null, we look at the whole model, not a submodel.
  	 * @param restrict BitSet for the set of states to restrict to.
  	 */
  	public abstract void computeMECStates(BitSet restrict) throws PrismException;
  
  	/**
  	 * Compute states of all accepting maximal end components (MECs) in the submodel obtained
  	 * by restricting this one to the set of states {@code restrict}, and store them,
  	 * where acceptance is defined as those which intersect with {@code accept}.
  	 * They can be retrieved using {@link #getMECStates()}.
  	 * If {@code restrict} is null, we look at the whole model, not a submodel.
  	 * If {@code accept} is null, the acceptance condition is trivially satisfied.
  	 * @param restrict BitSet for the set of states to restrict to
  	 * @param accept BitSet for the set of accepting states
  	 */
  	public abstract void computeMECStates(BitSet restrict, BitSet accept) throws PrismException;
  	
  	/**
  	 * Get the list of states for computed MECs.
  	 */
  	public abstract List<BitSet> getMECStates();
  }
  