Question

我想写一个条件来评估事实中的任何设置值是否满足条件。

这是我的规则定义：

public void evaluateRule(Facts facts, String ruleNum) {
        SpRuleDefinition spRuleDefinition = spRuleDefinitionService.findByRuleNum(ruleNum);
        System.out.println("Invoke Action : " + spRuleDefinition.getActionNum());
        facts.put("action", "ACTION1");
        MVELRule rule = new MVELRule()
                            .name("Rule1")
                            .description("My Rule")
                            .priority(1)
                            .when("shipment.orgNum=='ORG1' && (shipment.fromAddress.country=='IN' || shipment.toAddress.country=='IN') && shipment.shipmentLines.itemDetail.active==false")
                            .then("shipment.setOutcome(action);");
        Rules rules = new Rules();
        rules.register(rule);   
        //Fire rules on known facts
        RulesEngine rulesEngine = new DefaultRulesEngine();
        rulesEngine.fire(rules, facts);
    }

我传递的输入可能是这样的：

{“ orgNum”：“ ORG1”，“ fromAddress”：{“ country”：“ SGP”}，“ shipmentLines”：[{“ itemDetail”：{“ active”：true，“ countryOfOrigin”：“ IN” }，“ itemNum”：“ I1”，“ quantity”：10}，{“ itemDetail”：{“ active”：false，“ countryOfOrigin”：“ US”}，“ itemNum”：“ I2”，“ quantity”： 1}]，“ toAddress”：{“ country”：“ IN”}}

我想评估是否有任何一条装运线的itemDetail的活动标志设置为false。上面的规则失败，但有以下例外：

org.mvel2.PropertyAccessException: [Error: could not access: itemDetail; in class: java.util.HashSet]
[Near : {... s.country=='IN') && shipment.shipmentLines.itemDet ....}
]

Answer 1

这是MVEL问题，而不是EasyRules问题。

我想评估是否有任何一条装运线的itemDetail的活动标志设置为false。

您可以定义一个对集合进行迭代并检查条件的函数。这是一个示例：

@Test
public void testConditionOnSet() {
    Set<ItemDetail> itemDetailSet = new HashSet<>();
    itemDetailSet.add(new ItemDetail(false));
    itemDetailSet.add(new ItemDetail(false));
    itemDetailSet.add(new ItemDetail(true));

    String condition = "active = false;\n" +
            "foreach (itemDetail : itemDetails) {\n" +
            "   active = active && itemDetail.active;\n" +
            "}\n" +
            "System.out.println(\"Is there a non active itemDetail?: \" + !active);";
    Map facts = new HashMap();
    facts.put("itemDetails", itemDetailSet);

    Object result = MVEL.eval(condition, facts);
}

static class ItemDetail {
    private boolean active;

    public ItemDetail(boolean active) {
        this.active = active;
    }

    public boolean isActive() {
        return active;
    }
}

此示例打印：Is there a non active itemDetail? true。

希望这会有所帮助。

如何使用j-easy easy-rules编写条件以查找集合中的任何匹配值

1 个答案: