开始使用Drools
创建一个规则包
我们在project->src->main->resources文件夹下创建一个规则包，创建完后，我们需要在配置文件中生命一个该配置包的session，配置文件所在的目录为project->src->main->resources->META-INF->kmodule.xml,Drools jar包默认从此路径的的此文件中读取此配置XML文件。
配置示例：
<?xml version="1.0" encoding="UTF-8"?>
<kmodule xmlns="http://jboss.org/kie/6.0.0/kmodule">
<kbase name="rules" packages="nestlerules">
<ksession name="ksession-rules"/>
</kbase>
<kbase name="rules2" packages="nestlerules">
<ksession type="stateless" name="ksession-rules-stateless"/>
</kbase>
<!-- 订单确认页规则 -->
<kbase name="rules1" packages="checkrules">
<ksession name="ksession-rules1"/>
</kbase>
<!-- 订单保存时间的价格校验规则 -->
<kbase name="ordconfirmrules" packages="orderconfirmrules">
<ksession name="ksession-orderconfirm"/>
</kbase>
</kmodule>创建调用规则的帮助类
调用规则引擎的过程中，有一些通用的方法，我们先封装一下，方便使用，具体代码如下：
package com.drools.util;
import org.drools.core.event.AgendaGroupPoppedEvent;
import org.drools.core.event.AgendaGroupPushedEvent;
import org.drools.core.event.RuleFlowGroupActivatedEvent;
import org.drools.core.event.RuleFlowGroupDeactivatedEvent;
import org.kie.api.KieServices;
import org.kie.api.event.rule.AfterMatchFiredEvent;
import org.kie.api.event.rule.AgendaEventListener;
import org.kie.api.event.rule.BeforeMatchFiredEvent;
import org.kie.api.event.rule.MatchCancelledEvent;
import org.kie.api.event.rule.MatchCreatedEvent;
import org.kie.api.event.rule.ObjectDeletedEvent;
import org.kie.api.event.rule.ObjectInsertedEvent;
import org.kie.api.event.rule.ObjectUpdatedEvent;
import org.kie.api.event.rule.RuleRuntimeEventListener;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.StatelessKieSession;
public class KnowledgeSessionHelper {
/**
* @description 创建一个填装规则的方法
* @return
*/
public static KieContainer createRuleBase() {
KieServices ks = KieServices.Factory.get();
KieContainer kieContainer = ks.getKieClasspathContainer();
return kieContainer;
}
/**
* @description 创建一个无状态的与规则引擎交互的session
* StateFul 和 StateLess 的区别在于 Stateful 是可以完成推理的，即一条规则可以导致另一条规则的触发
* 所以也需要显示的调用下FireRules() 而StateLess是不支持规则推理的，所以规则自动触发
* @param kieContainer
* @param sessionName
* @return
*/
public static StatelessKieSession getStatelessKnowledgeSession(KieContainer kieContainer, String sessionName) {
StatelessKieSession kSession = kieContainer.newStatelessKieSession(sessionName);
return kSession;
}
/**
* @description 创建一个有状态的与规则引擎交互的session
* @param kieContainer
* @param sessionName
* @return
*/
public static KieSession getStatefulKnowledgeSession(KieContainer kieContainer, String sessionName) {
KieSession kSession = kieContainer.newKieSession(sessionName);
return kSession;
}
public static KieSession getStatefulKnowledgeSessionWithCallback(KieContainer kieContainer, String sessionName) {
KieSession session = getStatefulKnowledgeSession(kieContainer, sessionName);
session.addEventListener(new RuleRuntimeEventListener() {
@Override
public void objectDeleted(ObjectDeletedEvent arg0) {
// TODO Auto-generated method stub
System.out.println("Object retracted \n"
+ "new Content \n" + arg0.getOldObject().toString());
}
@Override
public void objectInserted(ObjectInsertedEvent arg0) {
// TODO Auto-generated method stub
System.out.println("Object inserted \n"
+ arg0.getObject().toString());
}
@Override
public void objectUpdated(ObjectUpdatedEvent arg0) {
// TODO Auto-generated method stub
System.out.println("Object was updated \n"
+ "new Content \n" + arg0.getOldObject().toString());
}
});
session.addEventListener(new AgendaEventListener() {
public void matchCreated(MatchCreatedEvent event) {
System.out.println("The rule "
+ event.getMatch().getRule().getName()
+ " can be fired in agenda");
}
public void matchCancelled(MatchCancelledEvent event) {
System.out.println("The rule "
+ event.getMatch().getRule().getName()
+ " cannot b in agenda");
}
public void beforeMatchFired(BeforeMatchFiredEvent event) {
System.out.println("The rule "
+ event.getMatch().getRule().getName()
+ " will be fired");
}
public void afterMatchFired(AfterMatchFiredEvent event) {
System.out.println("The rule "
+ event.getMatch().getRule().getName()
+ " has be fired");
}
@Override
public void afterRuleFlowGroupActivated(org.kie.api.event.rule.RuleFlowGroupActivatedEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void afterRuleFlowGroupDeactivated(org.kie.api.event.rule.RuleFlowGroupDeactivatedEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void agendaGroupPopped(org.kie.api.event.rule.AgendaGroupPoppedEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void agendaGroupPushed(org.kie.api.event.rule.AgendaGroupPushedEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void beforeRuleFlowGroupActivated(org.kie.api.event.rule.RuleFlowGroupActivatedEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void beforeRuleFlowGroupDeactivated(org.kie.api.event.rule.RuleFlowGroupDeactivatedEvent arg0) {
// TODO Auto-generated method stub
}
});
return session;
}
}使用示例
package com.drools.connectors;
import java.util.List;
import org.kie.api.runtime.KieContainer;
import org.kie.api.runtime.KieSession;
import org.kie.api.runtime.StatelessKieSession;
import com.drools.util.KnowledgeSessionHelper;
import com.gpersist.entity.ReturnValue;
import com.nestle.entity.act.InvoiceTrans;
import com.nestle.entity.act.InvoiceTransdetail;
import com.nestle.entity.ctm.CtmBase;
import com.nestle.entity.ord.OrdBase;
import com.nestle.entity.ord.OrdSubdetail;
public class OrderChange {
private String rulename = "";
public OrderChange(String name) {
rulename = name;
}
StatelessKieSession sessionStateless = null;
KieSession sessionStatefull = null;
static KieContainer kieContainer;
private OrderBase orderbase;
private ReturnValue rtv;
public OrderBase getOrderbase() {
return orderbase;
}
public void setOrderbase(OrderBase orderbase) {
this.orderbase = orderbase;
}
public ReturnValue getRtv() {
return rtv;
}
public void setRtv(ReturnValue rtv) {
this.rtv = rtv;
}
public void excute() {
kieContainer = KnowledgeSessionHelper.createRuleBase();
sessionStatefull = KnowledgeSessionHelper.getStatefulKnowledgeSession(kieContainer, rulename);
sessionStatefull.insert(orderbase);
sessionStatefull.insert(rtv);
int n = sessionStatefull.fireAllRules();
sessionStatefull.dispose();
System.out.println("共触发了"+n+"条规则");
}
}示例可见github
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