code: protected void addCriteria(String column, String operator) {
      if (this.sbClause.length() == 0) {
        this.sbClause.append("WHERE");
      } else {
        this.sbClause.append(" AND");
      }
      this.sbClause.append(' ');
      this.sbClause.append(column);
      this.sbClause.append(' ');
      this.sbClause.append(operator);
      this.sbClause.append(" ?");
    }
docs: Adds a parameterized selection criterion of the form "column [operator] ?"
  to the where clause.
  
  @param column Database column name.
  @param operator the operator to use to separate.