//Get interpolation variables used by the Pattern
Map<InterpolationVariable, Integer> ivs = new HashMap<InterpolationVariable, Integer>();
RuleModelVisitor rmv = new RuleModelVisitor( pattern,
ivs );
rmv.visit( pattern );
if ( ivs.size() > 0 ) {
//Ensure every key has a value and substitute keys for values
for ( InterpolationVariable variable : ivs.keySet() ) {