boon/src/main/java/org/boon/sort/Sort.java
public Comparator comparator( Map<String, FieldAccess> fields ) {
        if ( comparator == null ) {
            comparator = universalComparator(this.getName(), fields,
                    this.getType(), this.childComparators(fields));
        }
        return comparator;
    }
public Comparator comparator( Map<String, FieldAccess> fields ) {
        if ( comparator == null ) {
            comparator = universalComparator(this.getName(), fields,
                    this.getType(), this.childComparators(fields));
        }
        return comparator;
    }
This is what really does the magic. This is the comparator creator.