code: //==============================================================================
  //	
  //	Copyright (c) 2016-
  //	Authors:
  //	* Steffen Maercker <maercker@tcs.inf.tu-dresden.de> (TU Dresden)
  //	* 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.modelviews;
  
  import java.io.FileWriter;
  import java.io.IOException;
  import java.util.AbstractMap;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.PrimitiveIterator;
  import java.util.TreeMap;
  import java.util.function.IntFunction;
  
  import common.IteratorTools;
  import common.IterableStateSet;
  import common.iterable.MappingIterator;
  import explicit.DTMC;
  import explicit.Distribution;
  import explicit.SuccessorsIterator;
  import explicit.graphviz.Decorator;
  import prism.ModelType;
  import prism.Pair;
  import prism.PrismException;
  import prism.PrismLog;
  import prism.PrismUtils;
  
  /**
   * Base class for a DTMC view, i.e., a virtual DTMC that is obtained
   * by mapping from some other model on-the-fly.
   * <br>
   * The main job of sub-classes is to provide an appropriate
   * getTransitionsIterator() method. Several other methods, providing
   * meta-data on the model have to be provided as well. For examples,
   * see the sub-classes contained in this package.
   */
  public abstract class DTMCView extends ModelView implements DTMC, Cloneable
  {
  	public DTMCView()
  	{
  		super();
  	}
  
  	public DTMCView(final ModelView model)
  	{
  		super(model);
  	}
  
  
  
  	//--- Object ---
  
  	@Override
  	public String toString()
  	{
  		final IntFunction<Entry<Integer, Distribution>> getDistribution = new IntFunction<Entry<Integer, Distribution>>()
  		{
  			@Override
  			public final Entry<Integer, Distribution> apply(final int state)
  			{
  				final Distribution distribution = new Distribution(getTransitionsIterator(state));
  				return new AbstractMap.SimpleImmutableEntry<>(state, distribution);
  			}
  		};
  		String s = "trans: [ ";
  		final IterableStateSet states = new IterableStateSet(getNumStates());
  		final Iterator<Entry<Integer, Distribution>> distributions = new MappingIterator.FromInt<>(states, getDistribution);
  		while (distributions.hasNext()) {
  			final Entry<Integer, Distribution> dist = distributions.next();
  			s += dist.getKey() + ": " + dist.getValue();
  			if (distributions.hasNext()) {
  				s += ", ";
  			}
  		}
  		return s + " ]";
  	}
  
  
  
  	//--- Model ---
  
  	@Override
  	public ModelType getModelType()
  	{
  		return ModelType.DTMC;
  	}
  
  	@Override
  	public int getNumTransitions()
  	{
  		int numTransitions = 0;
  		for (int state = 0, numStates = getNumStates(); state < numStates; state++) {
  			numTransitions += getNumTransitions(state);
  		}
  		return numTransitions;
  	}
  
  	@Override
  	public SuccessorsIterator getSuccessors(final int state)
  	{
  		final Iterator<Entry<Integer, Double>> transitions = getTransitionsIterator(state);
  
  		return SuccessorsIterator.from(new PrimitiveIterator.OfInt() {
  			public boolean hasNext() {return transitions.hasNext();}
  			public int nextInt() {return transitions.next().getKey();}
  		}, true);
  	}
  
  	@Override
  	public void exportToPrismExplicitTra(final PrismLog log)
  	{
  		// Output transitions to .tra file
  		log.print(getNumStates() + " " + getNumTransitions() + "\n");
  		final TreeMap<Integer, Double> sorted = new TreeMap<>();
  		for (int state = 0, max = getNumStates(); state < max; state++) {
  			// Extract transitions and sort by destination state index (to match PRISM-exported files)
  			for (Iterator<Entry<Integer, Double>> transitions = getTransitionsIterator(state); transitions.hasNext();) {
  				final Entry<Integer, Double> transition = transitions.next();
  				sorted.put(transition.getKey(), transition.getValue());
  			}
  			// Print out (sorted) transitions
  			for (Entry<Integer, Double> transition : sorted.entrySet()) {
  				// Note use of PrismUtils.formatDouble to match PRISM-exported files
  				log.print(state + " " + transition.getKey() + " " + PrismUtils.formatDouble(transition.getValue()) + "\n");
  			}
  			sorted.clear();
  		}
  	}
  
  	@Override
  	public void exportToPrismLanguage(final String filename) throws PrismException
  	{
  		try (FileWriter out = new FileWriter(filename)) {
  			out.write(getModelType().keyword() + "\n");
  			out.write("module M\nx : [0.." + (getNumStates() - 1) + "];\n");
  			final TreeMap<Integer, Double> sorted = new TreeMap<Integer, Double>();
  			for (int state = 0, max = getNumStates(); state < max; state++) {
  				// Extract transitions and sort by destination state index (to match PRISM-exported files)
  				for (Iterator<Entry<Integer, Double>> transitions = getTransitionsIterator(state); transitions.hasNext();) {
  					final Entry<Integer, Double> transition = transitions.next();
  					sorted.put(transition.getKey(), transition.getValue());
  				}
  				// Print out (sorted) transitions
  				out.write("[]x=" + state + "->");
  				boolean first = true;
  				for (Entry<Integer, Double> transition : sorted.entrySet()) {
  					if (first)
  						first = false;
  					else
  						out.write("+");
  					// Note use of PrismUtils.formatDouble to match PRISM-exported files
  					out.write(PrismUtils.formatDouble(transition.getValue()) + ":(x'=" + transition.getKey() + ")");
  				}
  				out.write(";\n");
  				sorted.clear();
  			}
  			out.write("endmodule\n");
  		} catch (IOException e) {
  			throw new PrismException("Could not export " + getModelType() + " to file \"" + filename + "\"" + e);
  		}
  	}
  
  	@Override
  	public String infoString()
  	{
  		String s = "";
  		s += getNumStates() + " states (" + getNumInitialStates() + " initial)";
  		s += ", " + getNumTransitions() + " transitions";
  		return s;
  	}
  
  	@Override
  	public String infoStringTable()
  	{
  		String s = "";
  		s += "States:      " + getNumStates() + " (" + getNumInitialStates() + " initial)\n";
  		s += "Transitions: " + getNumTransitions() + "\n";
  		return s;
  	}
  
  
  
  	//--- DTMC ---
  
  	@Override
  	public int getNumTransitions(final int state)
  	{
  		return IteratorTools.count(getTransitionsIterator(state));
  	}
  
  	public static Entry<Integer, Pair<Double, Object>> attachAction(final Entry<Integer, Double> transition, final Object action)
  	{
  		final Integer state = transition.getKey();
  		final Double probability = transition.getValue();
  		return new AbstractMap.SimpleImmutableEntry<>(state, new Pair<>(probability, action));
  	}
  
  	@Override
  	public Iterator<Entry<Integer, Pair<Double, Object>>> getTransitionsAndActionsIterator(final int state)
  	{
  		final Iterator<Entry<Integer, Double>> transitions = getTransitionsIterator(state);
  		return new MappingIterator.From<>(transitions, transition -> attachAction(transition, null));
  	}
  
  
  	//--- ModelView ---
  
  	/**
  	 * @see explicit.DTMCExplicit#exportTransitionsToDotFile(int, PrismLog) DTMCExplicit
  	 **/
  	@Override
  	public void exportTransitionsToDotFile(int i, PrismLog out, Iterable<explicit.graphviz.Decorator> decorators)
  	{
  		Iterator<Map.Entry<Integer, Double>> iter = getTransitionsIterator(i);
  		while (iter.hasNext()) {
  			Map.Entry<Integer, Double> e = iter.next();
  			out.print(i + " -> " + e.getKey());
  
  			explicit.graphviz.Decoration d = new explicit.graphviz.Decoration();
  			d.setLabel(e.getValue().toString());
  			if (decorators != null) {
  				for (Decorator decorator : decorators) {
  					d = decorator.decorateProbability(i, e.getKey(), e.getValue(), d);
  				}
  			}
  
  			out.println(d.toString());
  		}
  	}
  }
  