java - Easy-Rules 规则引擎，不能同时触发多个事实

Question

我正在尝试扩展 Shop 教程以获得简单的规则 (shop) 以在多个 facts 上运行。在规则中编写条件时，我们使用“事实名称”调用函数，如下所示，

condition: "people.isAdult() == false"

因为people只是facts中一个对象实例的名字，像上面这样定义条件是不好的。我如何定义条件，使其遍历多个 facts。

我想要实现的是在规则引擎的一次点火中评估多个事实的规则。

当将一组具有相同事实名称的事实提供给规则引擎时，仅评估最后提供的一个。但是，当为每个事实分配不同的名称时，我无法为每个事实分配相同的条件。

下面是代码。假设 Person 类对所有成员都有基本的 get/set 函数。

规则.yml:

---
name: "regex"
description: "Check if regex pattern matches"
priority: 1
condition: "people.getPayload().matches(\".*12.*34$\") == true"
actions:
 - "System.out.println(\"There is a match\");"
---
name: "age"
description: "Check if person's age is > 18 and marks the person as adult"
priority: 2
condition: "people.age > 18"
actions:
  - "people.setAdult(true);"
---
name: "alkol"
description: "children are not allowed to buy alcohol"
priority: 3
condition: "people.isAdult() == false"
actions:
  - "System.out.println(\"Shop: Sorry, you are not allowed to buy portakal\");"

主要:

//create a person instance (fact)   
            Person [] PeopleArray = new Person [100];
            Person [] KidsArray = new Person [300];

        // initialize arrays
            for(int i = 0; i < PeopleArray.length ; i++)
            {
               PeopleArray[i] = new Person("TOM"+i,23);
               PeopleArray[i].setPayload(dummystring);
            }
            for(int i = 0; i < KidsArray.length ; i++)
            {
                KidsArray[i] = new Person("EMRE"+i,13);
                KidsArray[i].setPayload(dummystring);
            }


        Facts facts = new Facts();

        // create a rule set
        Rules rules = MVELRuleFactory.createRulesFrom(new FileReader("rules.yml"));

        RulesEngine rulesEngine = new DefaultRulesEngine();

        System.out.println("Tom: Hi! can I have some Vodka please?");

      //put the facts
        for(int i = 0; i < PeopleArray.length ; i++)
            facts.put("people", PeopleArray[i]);
        long start = System.currentTimeMillis();
        for(int i = 0; i < KidsArray.length ; i++)
            facts.put("people", KidsArray[i]);

        rulesEngine.fire(rules, facts);

Answer 1

Facts 对象本质上是一个 hashmap。因此，根据设计，您不能将两个事实放在同一个键上。

我在您的示例中看到 people 事实是一个数组。现在如何在 mvel 表达式中处理数组是另一回事了。老实说，我能给出的最佳答案是查看 MVEL 文档:https://github.com/imona/tutorial/wiki/MVEL-Guide#arrays

What I want to achieve is evaluate the rules on multiple facts in one fire of the rule engine.

我不确定这是否可以通过简单的规则实现。我认为你可以:

• 要么平面化你的事实
• 或者根据不同的事实多次调用fire

希望这对您有所帮助。