@Override
  public Object evaluate(ExecutionContext context) throws FunctionDomainException,
      TypeMismatchException, NameResolutionException, QueryInvocationTargetException {

    return expr.evaluate(context);
  }
evaluates sort criteria in order by clause
geode-core/src/main/java/org/apache/geode/cache/query/internal/CompiledSortCriterion.java