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;
  
  import java.util.BitSet;
  
  import prism.PrismException;
  
  /**
   * Abstract base class for a consumer of SCC information, for use with an {@code SCCComputer},
   * where each SCC is stored as a BitSet.
   * <br>
   * When a new SCC is discovered, {@code notifyNextSCC()} will be called with a {@code BitSet} of the
   * states in the SCC. When the SCC computation is finished, {@code notifyDone()} will be
   * called once.
   * <br>
   * By default, for each SCC a fresh BitSet is created. If the BitSets that are
   * passed to {@code notifyNextSCC} can be reused for the next call, the {@code reuseBitSet}
   * flag can be set in the constructor.
   */
  public abstract class SCCConsumerBitSet implements SCCConsumer
  {
  	private BitSet curSCC = null;
  	private boolean reuseBitSet = false;
  
  	/** Default constructor. Don't reuse the BitSets */
  	public SCCConsumerBitSet()
  	{
  		this(false);
  	}
  
  	/**
  	 * Constructor. If {@code reuseBitSet} is set, reuse the same BitSet for all
  	 * calls to {@code notifyNextSCC}.
  	 * @param reuseBitSet allow reuse of BitSets
  	 */
  	public SCCConsumerBitSet(boolean reuseBitSet)
  	{
  		this.reuseBitSet = reuseBitSet;
  		if (reuseBitSet)
  			curSCC = new BitSet();
  	}
  
  	@Override
  	public void notifyStartSCC() throws PrismException
  	{
  		if (reuseBitSet) {
  			curSCC.clear();
  		} else {
  			curSCC = new BitSet();
  		}
  	}
  
  	@Override
  	public void notifyStateInSCC(int stateIndex) throws PrismException
  	{
  		curSCC.set(stateIndex);
  	}
  
  	@Override
  	public void notifyEndSCC() throws PrismException
  	{
  		notifyNextSCC(curSCC);
  		if (!reuseBitSet) {
  			curSCC = null;
  		}
  	}
  
  	public abstract void notifyNextSCC(BitSet scc) throws PrismException;
  }
  