switch ( list.size() ) {
case 0:
constraints = new EmptyBetaConstraints();
break;
case 1:
constraints = new SingleBetaConstraints( list.get(0),
buildContext.getKnowledgeBase().getConfiguration() );
break;
case 2:
constraints = new DoubleBetaConstraints( list.toArray( new BetaNodeFieldConstraint[2] ),
buildContext.getKnowledgeBase().getConfiguration() );