code: protected ConditionOperator setupConditionOperator(final ConditionFormatter formatter, final Token.Condition token) {
  
          final Matcher matcher = PATTERN_CONDITION_OPERATOR.matcher(token.getValue());
          if(!matcher.matches()) {
              throw new IllegalArgumentException("not match condition:" + token.getValue());
          }
  
          final String operator = matcher.group(1);
          final String number = matcher.group(2);
          final double condition = Double.valueOf(number);
  
          final ConditionOperator conditionOperator;
          switch(operator) {
              case "=":
                  conditionOperator = new ConditionOperator.Equal(condition);
                  break;
              case "<>":
                  conditionOperator = new ConditionOperator.NotEqual(condition);
                  break;
              case ">":
                  conditionOperator = new ConditionOperator.GreaterThan(condition);
                  break;
              case "<":
                  conditionOperator = new ConditionOperator.LessThan(condition);
                  break;
              case ">=":
                  conditionOperator = new ConditionOperator.GreaterEqual(condition);
                  break;
              case "<=":
                  conditionOperator = new ConditionOperator.LessEqual(condition);
                  break;
              default:
                  logger.warn("unknown operator : {}", operator);
                  conditionOperator = ConditionOperator.ALL;
                  break;
  
          }
  
          formatter.setOperator(conditionOperator);
          return conditionOperator;
      }
docs: {@literal '[<=1000]'}などの数値の条件を組み立てる
  @param formatter 現在の組み立て中のフォーマッタのインスタンス。
  @param token 条件式のトークン。
  @return 演算子の条件式。
  @throws IllegalArgumentException 処理対象の条件として一致しない場合