package edu.stanford.peer.rbtm.engine;

import java.util.*;
import edu.stanford.peer.rbtm.credential.*;
/**
 * A map which keeps track of how many partial solutions reach a proof node,
 * using a decrementing counter, which is initialized to k for each 
 * intersection.
 */
public class PartialSolutionMap
{
	 /** table of decrementing counters, one per intersection */
	 HashMap counters = new HashMap();

	 /** get the count of outstanding partial solutions */
	 public int getPartialSolutionCount(Intersection inter) {
		  return ((Integer)counters.get(inter)).intValue();
	 }
	 
	 /**
	  * decrement the counter by 1 for the specified intersect, creating a 
	  * new counter, if necessary 
	  */
	 public boolean addPartialSolution(Intersection inter,EntityExpression expr)
	 {
		  int partialSolutionCount = -1;
		  try {
				partialSolutionCount = getPartialSolutionCount(inter);
		  } catch(NullPointerException nullEx) {
				partialSolutionCount = inter.getPartsCount();
		  } catch(Exception ex) {
				ex.printStackTrace();
		  }
		  counters.put(inter, new Integer(--partialSolutionCount));
		  return (partialSolutionCount == 0)? true: false;
	 }
}