5 代码示例
下面是使用Drools作为规则引擎实例的一个例子，规则文件使用了Drools的drl格式：
JSR94Sample.java
package com.sample;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import javax.rules.ConfigurationException;
import javax.rules.RuleRuntime;
import javax.rules.RuleServiceProvider;
import javax.rules.RuleServiceProviderManager;
import javax.rules.StatelessRuleSession;
import javax.rules.admin.LocalRuleExecutionSetProvider;
import javax.rules.admin.RuleAdministrator;
import javax.rules.admin.RuleExecutionSet;
import org.drools.jsr94.rules.RuleServiceProviderImpl;
public class JSR94Sample {
private static RuleServiceProvider ruleProvider;
private static void initProvider(){
String uri = RuleServiceProviderImpl.RULE_SERVICE_PROVIDER;
Class providerClass = RuleServiceProviderImpl.class;
try{
//注册ruleProvider
RuleServiceProviderManager.registerRuleServiceProvider(uri, providerClass);
//从RuleServiceProviderManager获取ruleProvider
ruleProvider = RuleServiceProviderManager.getRuleServiceProvider(uri);
}catch(ConfigurationException e){
e.printStackTrace();
}
}
private static void adminSample(){
try{
//获取RuleAdministrator实例
RuleAdministrator admin = ruleProvider.getRuleAdministrator();
//获取RuleExectuionSetProvider
HashMap properties = new HashMap();
properties.put("name", "My Rules");
properties.put("description", "A trivial rulebase");
LocalRuleExecutionSetProvider ruleExecutionSetProvider = admin.getLocalRuleExecutionSetProvider(properties);
//创建RuleExecutionSet
FileReader reader = new FileReader("bin/sample.drl");
RuleExecutionSet reSet = ruleExecutionSetProvider.createRuleExecutionSet(reader, properties);
//注册RuleExecutionSet
admin.registerRuleExecutionSet("mysample",reSet,properties);
}catch(Exception e){
e.printStackTrace();
}
}
private static void runtimeSampe(){
try{
//获取RuleRuntime, 创建会话
RuleRuntime runtime = ruleProvider.getRuleRuntime();
StatelessRuleSession ruleSession = (StatelessRuleSession)runtime.createRuleSession("mysample",null,RuleRuntime.STATELESS_SESSION_TYPE);
//初始化输入数据
Message message1 = new Message();
message1.setMessage("Hello World");
message1.setStatus(Message.HELLO);
Message message2 = new Message();
message2.setMessage("Goodbye World");
message2.setStatus(Message.GOODBYE);
List inputs = new ArrayList();
inputs.add(message1);
inputs.add(message2);
//执行规则
List results = ruleSession.executeRules(inputs);
for(int i=0;i){
Message msg = results.get(i);
System.out.println(msg.message);
}
//释放会话资源
ruleSession.release();
}catch(Exception e){
e.printStackTrace();
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
initProvider();
adminSample();
runtimeSampe();
}
public static class Message {
public static final int HELLO = 0;
public static final int GOODBYE = 1;
private String message;
private int status;
public String getMessage() {
return this.message;
}
public void setMessage(String message) {
this.message = message;
}
public int getStatus() {
return this.status;
}
public void setStatus(int status) {
this.status = status;
}
}
}
规则文件使用的就是在这里使用的例子。
Original: https://www.cnblogs.com/holbrook/archive/2012/12/07/2807026.html
Author: 心内求法
Title: 漫话规则引擎(4): Java规则引擎规范：JSR94
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