Drools-如何找出所有匹配的规则？

Posted 2023-02-19

【中文标题】Drools-如何找出所有匹配的规则？

【英文标题】：Drools- how to find out which all rules were matched?

【发布时间】：2013-11-25 22:36:36

【问题描述】：

我有一个 .DRL 文件，其中包含 10 条规则。一旦我插入一个事实，一些规则可能会被匹配——我如何找出哪些规则以编程方式匹配？

【参考方案1】：

您可以使用 RuleContext:drools 打印有关从 DRL 文件本身执行的规则的信息

System.out.println(drools.getRule().getName())

【参考方案2】：

请注意，此答案适用于 Drools 最高 5.x 的版本。如果您已升级到 6 或更高版本，请查看来自 @melchoir55 的修改后的答案。我自己没有测试过，但我相信它可以工作。

要跟踪规则激活，您可以使用 AgendaEventListener。下面是一个示例，如下所示：

https://github.com/gratiartis/sctrcd-payment-validation-web/blob/master/src/main/java/com/sctrcd/drools/util/TrackingAgendaEventListener.java

您只需要创建这样一个监听器并将其附加到会话中，如下所示：

ksession = kbase.newStatefulKnowledgeSession();
AgendaEventListener agendaEventListener = new TrackingAgendaEventListener();
ksession.addEventListener(agendaEventListener);
//...
ksession.fireAllRules();
//...
List<Activation> activations = agendaEventListener.getActivationList();

请注意，还有 WorkingMemoryEventListener，它使您能够跟踪事实的插入、更新和撤回。

用于跟踪和记录 AgendaEventListener 的代码：

package com.sctrcd.drools.util;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.drools.definition.rule.Rule;
import org.drools.event.rule.DefaultAgendaEventListener;
import org.drools.event.rule.AfterActivationFiredEvent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A listener that will track all rule firings in a session.
 * 
 * @author Stephen Masters
 */
public class TrackingAgendaEventListener extends DefaultAgendaEventListener 

    private static Logger log = LoggerFactory.getLogger(TrackingAgendaEventListener.class);

    private List<Activation> activationList = new ArrayList<Activation>();

    @Override
    public void afterActivationFired(AfterActivationFiredEvent event) 
        Rule rule = event.getActivation().getRule();

        String ruleName = rule.getName();
        Map<String, Object> ruleMetaDataMap = rule.getMetaData();

        activationList.add(new Activation(ruleName));
        StringBuilder sb = new StringBuilder("Rule fired: " + ruleName);

        if (ruleMetaDataMap.size() > 0) 
            sb.append("\n  With [" + ruleMetaDataMap.size() + "] meta-data:");
            for (String key : ruleMetaDataMap.keySet()) 
                sb.append("\n    key=" + key + ", value="
                        + ruleMetaDataMap.get(key));
            
        

        log.debug(sb.toString());
    

    public boolean isRuleFired(String ruleName) 
        for (Activation a : activationList) 
            if (a.getRuleName().equals(ruleName)) 
                return true;
            
        
        return false;
    

    public void reset() 
        activationList.clear();
    

    public final List<Activation> getActivationList() 
        return activationList;
    

    public String activationsToString() 
        if (activationList.size() == 0) 
            return "No activations occurred.";
         else 
            StringBuilder sb = new StringBuilder("Activations: ");
            for (Activation activation : activationList) 
                sb.append("\n  rule: ").append(activation.getRuleName());
            
            return sb.toString();
        
    

【讨论】：

请用@melchoir55 的答案更新您的答案，因为它不再适用于实际版本

【参考方案3】：

Steve 的回答是可靠的，但是 drools 6 带来的主要变化使代码过时了。我在下面发布了考虑到新 api 的史蒂夫代码的重写：

package your.preferred.package;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.drools.core.event.DefaultAgendaEventListener;
import org.kie.api.definition.rule.Rule;
import org.kie.api.event.rule.AfterMatchFiredEvent;
import org.kie.api.runtime.rule.Match;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A listener that will track all rule firings in a session.
 * 
 * @author Stephen Masters, Isaac Martin
 */
public class TrackingAgendaEventListener extends DefaultAgendaEventListener  

    private static Logger log = LoggerFactory.getLogger(TrackingAgendaEventListener.class);

    private List<Match> matchList = new ArrayList<Match>();

    @Override
    public void afterMatchFired(AfterMatchFiredEvent event) 
        Rule rule = event.getMatch().getRule();

        String ruleName = rule.getName();
        Map<String, Object> ruleMetaDataMap = rule.getMetaData();

        matchList.add(event.getMatch());
        StringBuilder sb = new StringBuilder("Rule fired: " + ruleName);

        if (ruleMetaDataMap.size() > 0) 
            sb.append("\n  With [" + ruleMetaDataMap.size() + "] meta-data:");
            for (String key : ruleMetaDataMap.keySet()) 
                sb.append("\n    key=" + key + ", value="
                        + ruleMetaDataMap.get(key));
            
        

        log.debug(sb.toString());
    

    public boolean isRuleFired(String ruleName) 
        for (Match a : matchList) 
            if (a.getRule().getName().equals(ruleName)) 
                return true;
            
        
        return false;
    

    public void reset() 
        matchList.clear();
    

    public final List<Match> getMatchList() 
        return matchList;
    

    public String matchsToString() 
        if (matchList.size() == 0) 
            return "No matchs occurred.";
         else 
            StringBuilder sb = new StringBuilder("Matchs: ");
            for (Match match : matchList) 
                sb.append("\n  rule: ").append(match.getRule().getName());
            
            return sb.toString();
        
    

【讨论】：

它会抛出异常：java.util.ConcurrentModificationException: null at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922) ~[na:1.7.0_60] at java.util。 HashMap$KeyIterator.next(HashMap.java:956) ~[na:1.7.0_60] at org.drools.core.impl.StatelessKnowledgeSessionImpl.registerCustomListeners(StatelessKnowledgeSessionImpl.java:188) ~[drools-core-6.2.0.Final .jar:6.2.0.Final] 在 org.drools.core.impl.StatelessKnowledgeSessionImpl.newWorkingMemory(StatelessKnowledgeSessionImpl.java:140)

【参考方案4】：

您可以使用静态记录器工厂，它将使用您最喜欢的记录器记录 DRL 文件中的操作。

例如：

import org.drools.runtime.rule.RuleContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class DRLLogger 

private DRLLogger() 


protected static Logger getLogger(final RuleContext drools) 
    final String category = drools.getRule().getPackageName() + "." + drools.getRule().getName();
    final Logger logger = LoggerFactory.getLogger(category);
    return logger;


public static void info(final RuleContext drools, final String message, final Object... parameters) 
    final Logger logger = getLogger(drools);
    logger.info(message, parameters);


public static void debug(final RuleContext drools, final String message, final Object... parameters) 
    final Logger logger = getLogger(drools);
    logger.debug(message, parameters);


public static void error(final RuleContext drools, final String message, final Object... parameters) 
    final Logger logger = getLogger(drools);
    logger.error(message, parameters);

然后从您的 DRL 文件中：

import function com.mycompany.DRLLogger.*

rule "myrule"
when
    $fact: Fact()
then
    info(drools, "Fact:", $fact);
end

【参考方案5】：

在 DRL 文件中将方言更改为 JAVA。

从 java 文件中插入一个 HashMap 到 DRL 文件（使用 Drools 会话概念）， 它应该包含规则名称作为键和布尔值作为结果。

关注link 了解如何将地图插入 DRL 文件。

您现在可以找到完全匹配的规则。

希望这会有所帮助:)