code: public void addConstraintMatch(ConstraintMatch constraintMatch) {
          score = score.add(constraintMatch.getScore());
          boolean added = constraintMatchSet.add(constraintMatch);
          if (!added) {
              throw new IllegalStateException("The indictment (" + this
                      + ") could not add constraintMatch (" + constraintMatch
                      + ") to its constraintMatchSet (" + constraintMatchSet + ").");
          }
      }
docs: ************************************************************************