1 files changed, 36 insertions, 4 deletions

diff --git a/src/jrummikub/ai/fdsolver/Var.java b/src/jrummikub/ai/fdsolver/Var.java
index eb6f432..e023f34 100644
--- a/src/jrummikub/ai/fdsolver/Var.java
+++ b/src/jrummikub/ai/fdsolver/Var.java
@@ -4,13 +4,16 @@ import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
 
-public class Var<T> {
+public class Var<T> implements Comparable<Var<T>> {
 	private Solver solver;
 	private HashSet<T> range;
+	private HashSet<Constraint> constraints;
+	private T recorded;
 
 	public Var(Solver solver, Collection<T> range) {
 		this.solver = solver;
 		this.range = new HashSet<T>(range);
+		constraints = new HashSet<Constraint>();
 	}
 
 	public T getValue() {
@@ -23,7 +26,7 @@ public class Var<T> {
 		return range;
 	}
 
-	public void choose(T value) {
+	void choose(T value) {
 		for (Iterator<T> i = this.iterator(); i.hasNext();) {
 			if (i.next() != value) {
 				i.remove();
@@ -31,15 +34,19 @@ public class Var<T> {
 		}
 	}
 
-	public void makeDirty() {
+	void makeDirty() {
 		this.solver.dirtyVars.add(this);
 	}
 
-	public void invalidate(T value) {
+	void invalidate(T value) {
 		range.remove(value);
 		solver.logInvalidation(this, value);
 		makeDirty();
 	}
+	
+	HashSet<Constraint> getConstraints() {
+		return constraints;
+	}
 
 	public Iterator<T> iterator() {
 		final Iterator<T> iterator = range.iterator();
@@ -69,10 +76,35 @@ public class Var<T> {
 			}
 		};
 	}
+	
+	void record() {
+		recorded = getValue();
+	}
+	
+	void restore() {
+		range.clear();
+		range.add(recorded);
+	}
 
 	@Override
 	public String toString() {
 		return "Var" + range;
 	}
+	
+	private int neighborCount() {
+		int count = 0;
+		for (Constraint constraint : constraints) {
+			count += constraint.getWatchedVars().size();
+		}
+		return count;
+	}
+	
+	@Override
+	public int compareTo(Var<T> other) {
+		int rangeCompare = ((Integer)range.size()).compareTo(other.range.size());
+		if (rangeCompare != 0)
+			return rangeCompare;
+		return ((Integer)neighborCount()).compareTo(other.neighborCount());
+	}
 
 }