• modify代表修改fact，会再次触发符合条件的rule
• 对象直接修改只是java 操作，不会会再次触发符合条件的rule

以下为测试代码-drl部分

package org.drools.learnimport org.drools.learn.ModifyTest.Message;global java.util.List listrule "Stateless modify"
// 注意使用了mvel，用java会报status 不是publicdialect "mvel"whenm : Message( status == Message.HELLO, message : message )thenSystem.out.println( message + " in thread " + Thread.currentThread().getId()+","+System.currentTimeMillis());modify ( m ) { message = "Goodbye cruel world",status = Message.GOODBYE };endrule "Stateless Good Bye"
// 注意使用了mveldialect "mvel"wheno : Message( status == Message.GOODBYE, message : message )thenSystem.out.println( " Stateless Good Bye in thread " + Thread.currentThread().getId()+","+System.currentTimeMillis());// 使用set 不会触发rule执行o.setMessage("changed by drl");o.setStatus (100);//  modify ( o ) { message = "100 cruel world",//                    status = 100 };endrule "Stateless 100 "dialect "java"auto-focus truewheno : Message( status == 100, message : message )thenSystem.out.println( " Stateless 100 should not be printed ,but it printed in  " + Thread.currentThread().getId()+","+System.currentTimeMillis());end

测试java代码package org.drools.learn;import org.drools.core.io.impl.ClassPathResource;
import org.kie.api.KieBase;
import org.kie.api.KieBaseConfiguration;
import org.kie.api.KieServices;
import org.kie.api.conf.EqualityBehaviorOption;
import org.kie.api.conf.SequentialOption;
import org.kie.api.io.Resource;
import org.kie.api.logger.KieRuntimeLogger;
import org.kie.api.runtime.StatelessKieSession;
import org.kie.internal.conf.ConsequenceExceptionHandlerOption;
import org.kie.internal.conf.MultithreadEvaluationOption;
import org.kie.internal.utils.KieHelper;import java.util.ArrayList;
import java.util.List;public class ModifyTest {private static KieBase kieBase;private static KieBaseConfiguration kieBaseConf;// private static KieSessionConfiguration kieBaseConf;public static final void main(final String[] args) {// From the kie services, a container is created from the classpathKieServices ks=KieServices.get();kieBaseConf= ks.newKieBaseConfiguration();//设置SequentialOption以提升性能kieBaseConf.setOption(SequentialOption.YES);//设置使用对象的equals函数来进行对象比较kieBaseConf.setOption(EqualityBehaviorOption.EQUALITY);//设置exception 捕获，不设置为默认使用org.drools.core.runtime.rule.impl.DefaultConsequenceExceptionHandlerkieBaseConf.setOption(ConsequenceExceptionHandlerOption.get(DroolsConsequenceExceptionHandler.class));// kieBaseConf.setOption(MultithreadEvaluationOption.YES);//使用resource模式装载，参考https://zhuanlan.zhihu.com/p/519969197Resource resource =new ClassPathResource("org/drools/learn/ModifyTest.drl");KieBase base=new KieHelper().addResource(resource).build(kieBaseConf);StatelessKieSession ksession = base.newStatelessKieSession();ArrayList result=new ArrayList<Object>();ksession.setGlobal( "list",  result);// The application can insert facts into the sessionMessage message = new Message();message.setMessage( "Hello World" );message.setStatus( Message.HELLO );ksession.execute( message );System.out.println("message status change to "+message.getStatus());}public static class Message {public static final int HELLO   = 0;public static final int GOODBYE = 1;private String          message;private int             status;public Message() {}public String getMessage() {return this.message;}public void setMessage(final String message) {this.message = message;}public int getStatus() {return this.status;}public void setStatus(final int status) {this.status = status;}public static Message doSomething(Message message) {return message;}public boolean isSomething(String msg,List<Object> list) {list.add( this );return this.message.equals( msg );}}}