easy-rules mvel yaml 格式规则配置&&试用二——rule 数据返回结果

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默认上easy-rules 的数据是没有返回值的，同时对于基于yaml 配置方式更是如此，官方给予我们了一种解决方法
就是基于pojo添加返回字段，但是基于yaml 配置的方式就不方便了，实际上我们可以通过组合的模式——添加一个
最总解决的rule（使用pojo）同时配置一个比较大的优先级，同时这个rule，永远都是执行的就可以解决了，以下是
一个实践

项目结构

详细的可以参考https://www.cnblogs.com/rongfengliang/p/12686702.html

• pom.xml

 

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

  <modelVersion>4.0.0</modelVersion>

  <groupId>com.dalong</groupId>

  <artifactId>myruleapps</artifactId>

  <version>1.0-SNAPSHOT</version>

  <properties>

    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

    <encoding>UTF-8</encoding>

    <java.version>1.8</java.version>

    <maven.compiler.source>1.8</maven.compiler.source>

    <maven.compiler.target>1.8</maven.compiler.target>

  </properties>

  <build>

    <plugins>

      <plugin>

        <groupId>org.apache.maven.plugins</groupId>

        <artifactId>maven-compiler-plugin</artifactId>

        <configuration>

          <source>8</source>

          <target>8</target>

        </configuration>

      </plugin>

    </plugins>

  </build>

  <packaging>jar</packaging>

  <dependencies>

    <dependency>

      <groupId>org.jeasy</groupId>

      <artifactId>easy-rules-core</artifactId>

      <version>3.4.0</version>

    </dependency>

    <dependency>

      <groupId>org.jeasy</groupId>

      <artifactId>easy-rules-mvel</artifactId>

      <version>3.4.0</version>

    </dependency>

    <dependency>

      <groupId>org.jeasy</groupId>

      <artifactId>easy-rules-spel</artifactId>

      <version>3.4.0</version>

    </dependency>

    <dependency>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-simple</artifactId>

      <version>1.7.25</version>

    </dependency>

  </dependencies>

</project>

• yaml规则

---

name: "1"

description: "1"

condition: "user.getAge()>26"

priority: 1

actions:

  - "user.age=user.age-2;System.out.println(user.userinfo);"

​

---

name: "2"

description: "2"

condition: "user.getAge()<26"

priority: 2

actions:

  - "UserService.doAction1(user)"

​

---

name: "3"

description: "3"

condition: "user.name.length<10"

priority: 3

actions:

  - "UserService.doAction2(user)"

​

---

name: "4"

description: "4"

condition: "user.name.length<40"

priority: 4

actions:

  - "System.out.println(\"rule4 \"+user.userinfo)"

​

---

name: "5"

description: "5"

condition: "user.name.length<30"

priority: 5

actions:

  - "UserService.doAction4(user.userinfo)"

​

---

name: "6"

description: "6"

condition: "user.name.length<30"

priority: 6

actions:

  - "System.out.println(\"rule6 \"+user.userinfo)"

​

---

name: "7"

description: "7"

condition: "user.name.length<30"

priority: 7

actions:

  - "UserService.doAction4(user)"

---

name: "8"

description: "8"

condition: "user.name.length<30"

priority: 8

actions:

  - "System.out.println(\"rule8 \"+user)"

• 最后必须执行的rule
  MyRule.java 优先级数字很大，最后执行
  

 

package com.dalong;

​

import org.jeasy.rules.annotation.Action;

import org.jeasy.rules.annotation.Condition;

import org.jeasy.rules.annotation.Fact;

import org.jeasy.rules.annotation.Rule;

import org.jeasy.rules.api.Facts;

​

@Rule(name = "100", description = "my rule description", priority = 100)

public class MyRule<T> {

​

    private boolean executed;

​

    private T result;

​

    @Condition

    public boolean when(@Fact("user") T fact) {

        //my rule conditions

        return true;

    }

​

    @Action(order = 1)

    public void then(@Fact("user") T facts) throws Exception {

        try {

            System.out.println("my rule has been executed");

            result = (T)facts; // assign your result here

            executed = true;

        } catch (Exception e) {

            // executed flag will remain false if an exception occurs

            throw e;

        }

    }

    public boolean isExecuted() {

        return executed;

    }

​

    public T getResult() {

        return result;

    }

}

代码集成

• 入口

package com.dalong;

​

import org.jeasy.rules.api.*;

import org.jeasy.rules.core.DefaultRulesEngine;

import org.jeasy.rules.core.InferenceRulesEngine;

import org.jeasy.rules.core.RuleBuilder;

import org.jeasy.rules.mvel.MVELRuleFactory;

import org.jeasy.rules.support.YamlRuleDefinitionReader;

import org.mvel2.ParserContext;

​

import java.io.FileReader;

import java.util.HashMap;

import java.util.Map;

​

import static com.dalong.DecreaseTemperatureAction.decreaseTemperature;

import static com.dalong.HighTemperatureCondition.itIsHot;

import static com.dalong.AppendUserName.appendUserName;

import static com.dalong.NameTooShort.nameTooShort;

​

public class Launcher {

​

    public static void main(String[] args) throws Exception {

       app3();

    }

​

    private static void app3() throws Exception {

        MVELRuleFactory ruleFactory = new MVELRuleFactory(new YamlRuleDefinitionReader());

        ParserContext context =new ParserContext();

        context.addImport("UserService", UserService.class);

        Rules yamlRules = ruleFactory.createRules(new FileReader(Launcher.class.getClassLoader().getResource("rules.yml").getFile()),context);

        DefaultRulesEngine rulesEngine = new DefaultRulesEngine();

        Facts facts = new Facts();

        // 此规则理论上应该走执行的

        MyRule<User> rule = new MyRule<User>();

        Map<Object,Object> userinfo = new HashMap<>();

        userinfo.put("name2","dalong");

        userinfo.put("age2",27);

        yamlRules.register(rule);

        User user =new User("dalong",27);

        user.setUserinfo(userinfo);

        facts.put("user",user);

        rulesEngine.registerRuleListener(new MyRulesListener());

        rulesEngine.registerRulesEngineListener(new MyRuleEngineListener());

        rulesEngine.fire(yamlRules, facts);

        // 规则执行完成之后，获取最后的结果

        if(rule.isExecuted()){

           User userResult= rule.getResult();

            System.out.println("result from final ruls"+userResult.toString());

        }

    }

}

说明

以及上参考资料的一个实践，实际中还是有点用的

参考资料

https://github.com/j-easy/easy-rules/wiki/faqs
https://www.cnblogs.com/rongfengliang/p/12686702.html