Question

我有一个原创的Cayenne Expression

(effectiveDate >= 01/01/2015) and ((specialFeaturesString like "*808*") and ((amortizationType = "05") or (amortizationType = "06")) and (loanType = 2))

我的代码库中有一个util方法，它将上面的表达式转换为HashMap。我遍历地图并转换为JSON格式并将该JSON提供给jquery QueryBuilder。我在UI层更改了JSON，并使用Jackson将JSON转换为HashMap HashMap sysout如下所示

{condition=AND, rules=[{id=effectiveDate, field=effectiveDate, type=date, input=text, operator=greater_or_equal, value=04/05/2016}, {condition=AND, rules=[{id=specialFeaturesString, field=specialFeaturesString, type=string, input=text, operator=contains, value="*808*"}, {condition=OR, rules=[{id=amortizationType, field=amortizationType, type=string, input=select, operator=equal, value=05}, {id=amortizationType, field=amortizationType, type=string, input=select, operator=equal, value=06}]}, {id=loanType, field=loanType, type=string, input=select, operator=equal, value=2}]}]}

我需要遍历HashMap并将其转换为Cayenne Expression。

最终结果应为

(effectiveDate >= 04/05/2016) and ((specialFeaturesString like "*808*") and ((amortizationType = "05") or (amortizationType = "06")) and (loanType = 2))

请提供代码

Answer 1

这是一个递归解析器的框架，可以帮助您入门：

public class ExpressionParser {

    public SimpleNode parse(Map<String, Object> map) {

        SimpleNode e = expForAggregateCondition(map);

        if (e == null) {
            e = expForRule(map);
        } else {

            Collection<Map<String, Object>> rules = 
              (Collection<Map<String, Object>>) map.get("rules");
            if (rules != null) {
                for (Map<String, Object> submap : rules) {

                    SimpleNode subExp = parse(submap);
                    e.jjtAddChild(subExp, e.jjtGetNumChildren());
                }
            }
        }

        return e;
    }

    private SimpleNode expForAggregateCondition(Map<String, Object> map) {
        String condition = (String) map.get("condition");
        if (condition == null) {
            return null;
        }

        switch (condition) {
        case "AND":
            return new ASTAnd();
        case "OR":
            return new ASTOr();
        default:
            throw new IllegalArgumentException("Bad condition: " + condition);
        }
    }

    private SimpleNode expForRule(Map<String, Object> map) {
        // TODO...
    }

}

将expForRule方法更新为

  private SimpleNode expForRule(Map<String, Object> map) {
    return (SimpleNode) ExpressionFactory.matchExp((String) map.get("id"), map.get("value"));
}

这导致

effectiveDate = "04/05/2016" and specialFeaturesString = "\"*808*\"" and amortizationType = "05" or amortizationType = "06" and loanType = "2"

不带括号。

HashMap到cayenne Expression

1 个答案: