Simple use of drools decision table

One 、 background

In the previous post , Our business rules are written in drl In file , This is no problem for developers , Business people are not very friendly , Let's briefly learn about this article drools Use of decision tables in , The rule is written in excel In file .

Two 、 A simple decision table

In the picture above ResultSet and ResultTable Is a must , _{And in the same bag , We'd better upload only one decision table .}

1、 Process multiple in the same decision table Sheet page

2、RuleSet What properties can be found below

Label	Value	Usage
RuleSet	The package name for the generated DRL file. Optional, the default is rule_table.	Must be the first entry.
Sequential	true or false. If true, then salience is used to ensure that rules fire from the top down.	Optional, at most once. If omitted, no firing order is imposed.
SequentialMaxPriority	Integer numeric value	Optional, at most once. In sequential mode, this option is used to set the start value of the salience. If omitted, the default value is 65535.
SequentialMinPriority	Integer numeric value	Optional, at most once. In sequential mode, this option is used to check if this minimum salience value is not violated. If omitted, the default value is 0.
EscapeQuotes	true or false. If true, then quotation marks are escaped so that they appear literally in the DRL.	Optional, at most once. If omitted, quotation marks are escaped.
IgnoreNumericFormat	true or false. If true, then the format for numeric values is ignored, for example, percent and currency.	Optional, at most once. If omitted, DRL takes formatted values.
Import	A comma-separated list of Java classes to import from another package.	Optional, may be used repeatedly.
Variables	Declarations of DRL globals (a type followed by a variable name). Multiple global definitions must be separated by commas.	Optional, may be used repeatedly.
Functions	One or more function definitions, according to DRL syntax.	Optional, may be used repeatedly.
Queries	One or more query definitions, according to DRL syntax.	Optional, may be used repeatedly.
Declare	One or more declarative types, according to DRL syntax.	Optional, may be used repeatedly.
Unit	The rule units that the rules generated from this decision table belong to.	Optional, at most once. If omitted, the rules do not belong to any unit.
Dialect	java or mvel. The dialect used in the actions of the decision table.	Optional, at most once. If omitted, java is imposed.

ResultSet： There can only be one area .

3、RuleTable What properties can be found below

Label	Or custom label that begins with	Value	Usage
NAME	N	Provides the name for the rule generated from that row. The default is constructed from the text following the RuleTable tag and the row number.	At most one column.
DESCRIPTION	I	Results in a comment within the generated rule.	At most one column.
CONDITION	C	Code snippet and interpolated values for constructing a constraint within a pattern in a condition.	At least one per rule table.
ACTION	A	Code snippet and interpolated values for constructing an action for the consequence of the rule.	At least one per rule table.
METADATA	@	Code snippet and interpolated values for constructing a metadata entry for the rule.	Optional, any number of columns.

See the above figure for specific use

4、 Writing rule attributes

stay ResultSet and ResultTable Rule attributes can be written here .ResultSet Local rule attributes will affect all rules under the same package , and ResultTable The rule properties of this place , Only this rule is affected .ResultTable Higher priority .

The supported rule attributes are ：PRIORITY、DATE-EFFECTIVE、DATE-EXPIRES、NO-LOOP、AGENDA-GROUP、ACTIVATION-GROUP、DURATION、TIMER、CALENDAR、AUTO-FOCUS、LOCK-ON-ACTIVE、RULEFLOW-GROUP.

Specific usage ： See above ACTIVATION-GROUP Use .

3、 ... and 、 demand

We need to score according to the students' grades , Give the corresponding results . The following rules ：

Rules for special treatment ：
Rule one ： As long as the name is Zhang San Of , Directly determine as optimal
Rule 2 ： As long as the name is Li Si Of , If Fraction in 0,60 Between , Think directly of as commonly

Common rules ：
Rule three ： Fraction in 0,60 Between think is fail,
Rule 4 ： Fraction in 60,70 Between think is commonly
Rule five ： Fraction in 70,90 Between think is good
Rule 6 ： Fraction in 90,100 Between think is optimal

From the rules above , We can see that the name is Zhang San and Li Si Of the students were specially treated .

Four 、 Realization

1、 Project implementation structure diagram

2、 introduce jar package

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-bom</artifactId>
            <type>pom</type>
            <version>7.69.0.Final</version>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-compiler</artifactId>
    </dependency>
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-mvel</artifactId>
    </dependency>
    <!--  Decision table  -->
    <dependency>
        <groupId>org.drools</groupId>
        <artifactId>drools-decisiontables</artifactId>
    </dependency>
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>1.2.11</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.22</version>
    </dependency>
</dependencies>

3、 To write kmodule.xml file

<kmodule xmlns="http://www.drools.org/xsd/kmodule">
    <kbase name="kabse" packages="rules.decision.tables" default="false">
        <ksession name="ksession" default="false" type="stateful"/>
    </kbase>
</kmodule>

4、 Write student entity classes

@Getter
@Setter
@ToString
public class Student {
    

    private String name;
    //  The score can only be in  0-100  Between 
    private Integer score;

    public Student(String name, Integer score) {
    
        this.name = name;
        if (null == score || score < 0 || score > 100) {
    
            throw new RuntimeException(" The score can only be in 0-100 Between ");
        }
        this.score = score;
    }
}

5、 Prepare decision table

6、 Convert the decision table to drl file

This step is mainly to check whether our decision table is written correctly , Look at the resulting drl What is the file like .

1、 The decision table is converted to drl File code

/** *  The decision table is converted to  drl  file  */
public static void decisionTable2Drl() throws IOException {
    
    Resource resource = ResourceFactory.newClassPathResource("rules/decision/tables/student-score.xlsx", "UTF-8");
    InputStream inputStream = resource.getInputStream();
    SpreadsheetCompiler compiler = new SpreadsheetCompiler();
    String drl = compiler.compile(inputStream, InputType.XLS);
    log.info(" Decision table conversion drl The content is :\r{}", drl);

    //  Check it out  drl  Is there a problem with the file 
    KieHelper kieHelper = new KieHelper();
    Results results = kieHelper.addContent(drl, ResourceType.DRL).verify();
    List<Message> messages = results.getMessages(Message.Level.ERROR);
    if (null != messages && !messages.isEmpty()) {
    
        for (Message message : messages) {
    
            log.error(message.getText());
        }
    }
}

2、 Translate into concrete drl File for

package rules.decision.tables;
//generated from Decision Table
import java.lang.StringBuilder;
import com.huan.drools.Student;
global java.lang.StringBuilder resultsInfo;



// rule values at B15, header at B10
rule "student-score-name-1"
/* 1、 Special treatment for Zhang San  2、 The name of the custom rule  */
	salience 65535
	activation-group "score"
	when
		$stu: Student(name == " Zhang San ")
	then
		resultsInfo.append(" Special treatment for Zhang San ：");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
		resultsInfo.append(" optimal ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

// rule values at B16, header at B10
rule "student-score_16"
	salience 65534
	activation-group "score"
	when
		$stu: Student(name == " Li Si ", score > 0 && score < 60)
	then
		resultsInfo.append(" Special treatment of the fourth part of Li ：");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
		resultsInfo.append(" commonly ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

// rule values at B17, header at B10
rule "student-score_17"
	salience 65533
	activation-group "score"
	when
		$stu: Student(score > 0 && score < 60)
	then
		resultsInfo.append(" fail, ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

// rule values at B18, header at B10
rule "student-score_18"
	salience 65532
	activation-group "score"
	when
		$stu: Student(score > 60 && score < 70)
	then
		resultsInfo.append(" commonly ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

// rule values at B19, header at B10
rule "student-score_19"
	salience 65531
	activation-group "score"
	when
		$stu: Student(score > 70 && score < 90)
	then
		resultsInfo.append(" good ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

// rule values at B20, header at B10
rule "student-score_20"
	salience 65530
	activation-group "score"
	when
		$stu: Student(score > 90 && score < 100)
	then
		resultsInfo.append(" optimal ");
System.out.println(" The rules :" + drools.getRule().getName() + "  Yes .");
end

You can see from the top The first rule Of Rule name It's different , And there is some descriptive information , This is specially handled in the decision table .

7、 test

1、 Write test code

package com.huan.drools;

import lombok.extern.slf4j.Slf4j;
import org.drools.decisiontable.InputType;
import org.drools.decisiontable.SpreadsheetCompiler;
import org.kie.api.KieServices;
import org.kie.api.builder.Message;
import org.kie.api.builder.Results;
import org.kie.api.io.Resource;
import org.kie.api.io.ResourceType;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.kie.internal.io.ResourceFactory;
import org.kie.internal.utils.KieHelper;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/** * drools  Use of decision tables  */
@Slf4j
public class DroolsDecisionTableApplication {
    
    public static void main(String[] args) throws IOException {
    
        decisionTable2Drl();
        KieServices kieServices = KieServices.get();
        KieContainer kieContainer = kieServices.newKieClasspathContainer();
        //  Although Zhang San had to 20 branch , But judging by the rules , The result should be   optimal 
        invokedDecisionTable(kieContainer, new Student(" Zhang San ", 20));
        //  Although Li Si had to 20 branch , But judging by the rules , The result should be   commonly 
        invokedDecisionTable(kieContainer, new Student(" Li Si ", 20));
        //  Liside 75 branch , But judging by the rules , The result should be   good 
        invokedDecisionTable(kieContainer, new Student(" Li Si ", 75));
        //  Wang Wude 59 branch , But judging by the rules , The result should be   fail, 
        invokedDecisionTable(kieContainer, new Student(" Wang Wu ", 59));
        //  Zhaoliude 20 branch , But judging by the rules , The result should be   commonly 
        invokedDecisionTable(kieContainer, new Student(" Zhao Liu ", 65));
        //  Qian Qide 20 branch , But judging by the rules , The result should be   good 
        invokedDecisionTable(kieContainer, new Student(" Qian Qi ", 75));
        //  Libade 20 branch , But judging by the rules , The result should be   optimal 
        invokedDecisionTable(kieContainer, new Student(" Li ba ", 95));
    }

    public static void invokedDecisionTable(KieContainer kieContainer, Student student) {
    
        System.out.println("\r");
        KieSession kieSession = kieContainer.newKieSession("ksession");
        StringBuilder result = new StringBuilder();
        kieSession.setGlobal("resultsInfo", result);
        kieSession.insert(student);
        kieSession.fireAllRules();
        kieSession.dispose();
        System.out.println(" Rule execution results ：" + result);
    }

    /** *  The decision table is converted to  drl  file  */
    public static void decisionTable2Drl() throws IOException {
    
        Resource resource = ResourceFactory.newClassPathResource("rules/decision/tables/student-score.xlsx", "UTF-8");
        InputStream inputStream = resource.getInputStream();
        SpreadsheetCompiler compiler = new SpreadsheetCompiler();
        String drl = compiler.compile(inputStream, InputType.XLS);
        log.info(" Decision table conversion drl The content is :\r{}", drl);
        //  Check it out  drl  Is there a problem with the file 
        KieHelper kieHelper = new KieHelper();
        Results results = kieHelper.addContent(drl, ResourceType.DRL).verify();
        List<Message> messages = results.getMessages(Message.Level.ERROR);
        if (null != messages && !messages.isEmpty()) {
    
            for (Message message : messages) {
    
                log.error(message.getText());
            }
        }
    }
}

2、 test result

It can be seen from the above figure , Our rules have been implemented normally .

5、 ... and 、 Complete code

https://gitee.com/huan1993/spring-cloud-parent/tree/master/drools/drools-decision-table

6、 ... and 、 Reference documents

1、https://docs.drools.org/7.69.0.Final/drools-docs/html_single/index.html#decision-tables-con_decision-tables