code: @Override
      public Expression<Long> count(Expression<?> arg0)
      {
          // TODO Auto-generated method stub
          String arg1 = "Count("+arg0.getAlias()+")";
          return new AggregateExpression(arg0, arg1);
      }
docs: /*
  (non-Javadoc)
  
  @see
  javax.persistence.criteria.CriteriaBuilder#count(javax.persistence.criteria
  .Expression)