[Drools]JAVA规则引擎 -- Drools 2

上一篇文章 http://blog.csdn.net/quzishen/archive/2011/01/25/6163012.aspx 描述了一些常用的drools的语法标签和一个模拟实例即发送积分的场景，这一片优化了一下代码，在此贴一下，希望有这方面使用经验的朋友多多交流沟通，指正不足。

通常而言，习惯上我们将规则放到文件系统中，比如以drl结尾的规则文件，现在我们要扩充一下，使其放到数据库中，以供多台服务器同时使用，同时依然保留文件系统的支持。

先看下一个接口：

/**
 * 规则接口
 * @author quzishen
 */
public interface PointRuleEngine {

    /**
     * 初始化规则引擎
     */
    public void initEngine();

    /**
     * 刷新规则引擎中的规则
     */
    public void refreshEnginRule();

    /**
     * 执行规则引擎
     * @param pointDomain 积分Fact
     */
    public void executeRuleEngine(final PointDomain pointDomain);
}

实现过程没有任何难度，两种方式封装过程只在于读取规则的方式不同，代码很简单：

package com.drools.demo.point;

import <a href="http://lib.csdn.net/base/17" class='replace_word' title="Java EE知识库" target='_blank' style='color:#df3434; font-weight:bold;'>Java</a>.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
import org.drools.RuleBase;
import org.drools.StatefulSession;
import org.drools.compiler.PackageBuilder;
import org.drools.spi.Activation;

/**
 * 规则接口实现类
 *
 * @author quzishen
 */
public class PointRuleEngineImpl implements PointRuleEngine {
    // ~~~ instance filed begin
    /** RuleBase */
    private RuleBase ruleBase;
    // ~~~ instance filed end

    /*
     * (non-Javadoc)
     * @see com.drools.demo.point.PointRuleEngine#initEngine()
     */
    public void initEngine() {
        // 设置时间格式
        System.setProperty("drools.dateformat", "yyyy-MM-dd HH:mm:ss");
        try {
            synchronized (this) {
                ruleBase = RuleBaseFacatory.getRuleBase();
                // 优先从DB加载规则，如果没有加载到或者加载错误，则从文件系统加载
                PackageBuilder backageBuilder = getPackBuilderFromDrlDB();
                backageBuilder = null == backageBuilder ? getPackageBuilderFromDrlFile()
                        : backageBuilder;

                ruleBase.addPackages(backageBuilder.getPackages());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
     * (non-Javadoc)
     * @see com.drools.demo.point.PointRuleEngine#refreshEnginRule()
     */
    public void refreshEnginRule() {
        ruleBase = RuleBaseFacatory.getRuleBase();
        synchronized (ruleBase) {
            // 删除所有的添加的Package
            org.drools.rule.Package[] packages = ruleBase.getPackages();
            for (org.drools.rule.Package pg : packages) {
                ruleBase.removePackage(pg.getName());
            }

            // 重新初始化规则引擎
            initEngine();
        }
    }

    /*
     * (non-Javadoc)
     * @see com.drools.demo.point.PointRuleEngine#executeRuleEngine(com.drools.demo.point.PointDomain)
     */
    public void executeRuleEngine(final PointDomain pointDomain) {
        if (null == ruleBase.getPackages() || 0 == ruleBase.getPackages().length) {
            return;
        }

        StatefulSession statefulSession = ruleBase.newStatefulSession();
        statefulSession.insert(pointDomain);

        // fire
        statefulSession.fireAllRules(new org.drools.spi.AgendaFilter() {
            public boolean accept(Activation activation) {
                return !activation.getRule().getName().contains("_test");
            }
        });

        statefulSession.dispose();
    }

    /**
     * 从Drl规则文件中读取规则
     *
     * @return
     * @throws Exception
     */
    private PackageBuilder getPackageBuilderFromDrlFile() {
        // 装载规则文件
        List<Reader> readers;
        try {
            readers = buildReadersFromDrlFile();
            // 装载PackageBuilder
            return buildPackageBuilder(readers);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 从Drl规则DB中读取规则
     *
     * @return
     * @throws Exception
     */
    private PackageBuilder getPackBuilderFromDrlDB() {
        // 装载规则
        List<Reader> readers = buildReadersFromDrlDB();

        // 装载PackageBuilder
        try {
            return buildPackageBuilder(readers);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 装载db中的规则到List<Reader>
     *
     * @return
     */
    private List<Reader> buildReadersFromDrlDB() {
        List<Reader> readers = new ArrayList<Reader>();
        // 获取脚本
        List<DroolsRuleDomain> drlRuleDomains = getRuleFromDB();

        if (null == drlRuleDomains) {
            return readers;
        }

        for (DroolsRuleDomain droolsRuleDomain : drlRuleDomains) {
            String ruleContext = droolsRuleDomain.getRuleContext();

            Reader br = new StringReader(ruleContext);
            readers.add(br);
        }
        return readers;
    }

    /**
     * 装载PackageBuilder
     *
     * @param readers
     * @return
     * @throws Exception
     */
    private PackageBuilder buildPackageBuilder(List<Reader> readers)
            throws Exception {
        if (null == readers || 0 == readers.size()) {
            return null;
        }

        PackageBuilder backageBuilder = new PackageBuilder();
        for (Reader r : readers) {
            backageBuilder.addPackageFromDrl(r);
        }

        // 检查脚本是否有问题
        if (backageBuilder.hasErrors()) {
            throw new Exception(backageBuilder.getErrors().toString());
        }

        return backageBuilder;
    }

    /**
     * 装载规则文件到Reader中
     *
     * @return
     * @throws FileNotFoundException
     */
    private List<Reader> buildReadersFromDrlFile() throws FileNotFoundException {
        // 获取脚本文件
        List<String> drlFilePath = getRuleDrlFile();
        // 装载脚本文件
        return readRuleFromDrlFile(drlFilePath);
    }

    /**
     * 从规则文件中读取规则
     *
     * @param drlFilePath 脚本文件路径
     * @return
     * @throws FileNotFoundException
     */
    private List<Reader> readRuleFromDrlFile(List<String> drlFilePath)
            throws FileNotFoundException {
        if (null == drlFilePath || 0 == drlFilePath.size()) {
            return null;
        }

        List<Reader> readers = new ArrayList<Reader>();

        for (String ruleFilePath : drlFilePath) {
            readers.add(new FileReader(new File(ruleFilePath)));
        }

        return readers;
    }

    /**
     * 从数据库中获取规则脚本内容
     *
     * @return
     */
    private List<DroolsRuleDomain> getRuleFromDB() {
        // 测试代码
        List<DroolsRuleDomain> droolsRuleDomains = new ArrayList<DroolsRuleDomain>();

        DroolsRuleDomain d1 = new DroolsRuleDomain();
        d1.setId(1);
        d1.setRuleContext("package com.drools.demo.point" + "/n" +
                "import com.drools.demo.point.PointDomain;" + "/n" +
                "rule birthdayPoint" + "/n" +
                "// 过生日，则加10分，并且将当月交易比数翻倍后再计算积分" + "/n" +
                "salience 100" + "/n" +
                "lock-on-active true" + "/n" +
                "when" + "/n" +
                "$pointDomain : PointDomain(birthDay == true)" + "/n" +
                "then" + "/n" +
                "$pointDomain.setPoint($pointDomain.getPoint()+10);" + "/n" +
                "$pointDomain.recordPointLog($pointDomain.getUserName(),/"birthdayPoint/");" + "/n" +
                "end");

        d1.setRuleName("testRule");
        d1.setVersion(1);

        droolsRuleDomains.add(d1);

        return droolsRuleDomains;
    }

    /**
     * 获取规则文件
     *
     * @return
     */
    private List<String> getRuleDrlFile() {
        List<String> drlFilePath = new ArrayList<String>();
        drlFilePath
                .add("D:/workspace2/DroolsDemo/src/com/drools/demo/point/addpoint.drl");
        drlFilePath
                .add("D:/workspace2/DroolsDemo/src/com/drools/demo/point/subpoint.drl");

        return drlFilePath;
    }
}

其中的getRuleFromDB() 和 getRuleDrlFile() 两个方法即可以重写以接入个人系统，现在其中编写的是测试代码。

其他的文件与上篇文章相同：

RuleBaseFacatory

package com.drools.demo.point;

import org.drools.RuleBase;
import org.drools.RuleBaseFactory;

/**
 * RuleBaseFacatory 单实例RuleBase生成工具
 * @author quzishen
 */
public class RuleBaseFacatory {
    private static RuleBase ruleBase;

    public static RuleBase getRuleBase(){
        return null != ruleBase ? ruleBase : RuleBaseFactory.newRuleBase();
    }
}

DroolsRuleDomain

package com.drools.demo.point;

/**
 * 规则内容domain
 *
 * @author quzishen
 */
public class DroolsRuleDomain {
    /** 数据库记录ID */
    private long id;
    /** 规则名称 */
    private String ruleName;
    /** 规则正文  */
    private String ruleContext;
    /** 规则版本 */
    private int version;
    /** 规则脚本状态 */
    private int status;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getRuleName() {
        return ruleName;
    }

    public void setRuleName(String ruleName) {
        this.ruleName = ruleName;
    }

    public String getRuleContext() {
        return ruleContext;
    }

    public void setRuleContext(String ruleContext) {
        this.ruleContext = ruleContext;
    }

    public int getVersion() {
        return version;
    }

    public void setVersion(int version) {
        this.version = version;
    }

    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }

}

PointDomain

package com.drools.demo.point;


/**
 * 积分计算对象
 * @author quzishen
 */
public class PointDomain {
    // 用户名
    private String userName;
    // 是否当日生日
    private boolean birthDay;
    // 增加积分数目
    private long point;
    // 当月购物次数
    private int buyNums;
    // 当月退货次数
    private int backNums;
    // 当月购物总金额
    private double buyMoney;
    // 当月退货总金额
    private double backMondy;
    // 当月信用卡还款次数
    private int billThisMonth;

    /**
     * 记录积分发送流水，防止重复发放
     * @param userName 用户名
     * @param type 积分发放类型
     */
    public void recordPointLog(String userName, String type){
        System.out.println("增加对"+userName+"的类型为"+type+"的积分操作记录.");
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public boolean isBirthDay() {
        return birthDay;
    }

    public void setBirthDay(boolean birthDay) {
        this.birthDay = birthDay;
    }

    public long getPoint() {
        return point;
    }

    public void setPoint(long point) {
        this.point = point;
    }

    public int getBuyNums() {
        return buyNums;
    }

    public void setBuyNums(int buyNums) {
        this.buyNums = buyNums;
    }

    public int getBackNums() {
        return backNums;
    }

    public void setBackNums(int backNums) {
        this.backNums = backNums;
    }

    public double getBuyMoney() {
        return buyMoney;
    }

    public void setBuyMoney(double buyMoney) {
        this.buyMoney = buyMoney;
    }

    public double getBackMondy() {
        return backMondy;
    }

    public void setBackMondy(double backMondy) {
        this.backMondy = backMondy;
    }

    public int getBillThisMonth() {
        return billThisMonth;
    }

    public void setBillThisMonth(int billThisMonth) {
        this.billThisMonth = billThisMonth;
    }

}

addpoint.drl

package com.drools.demo.point

import com.drools.demo.point.PointDomain;

rule birthdayPoint
    // 过生日，则加10分，并且将当月交易比数翻倍后再计算积分
    salience 100
    lock-on-active true
    when
        $pointDomain : PointDomain(birthDay == true)
    then
        $pointDomain.setPoint($pointDomain.getPoint()+10);
        $pointDomain.setBuyNums($pointDomain.getBuyNums()*2);
        $pointDomain.setBuyMoney($pointDomain.getBuyMoney()*2);
        $pointDomain.setBillThisMonth($pointDomain.getBillThisMonth()*2);

        $pointDomain.recordPointLog($pointDomain.getUserName(),"birthdayPoint");
end

rule billThisMonthPoint
    // 2011-01-08 - 2011-08-08每月信用卡还款3次以上，每满3笔赠送30分
    salience 99
    lock-on-active true
    date-effective "2011-01-08 23:59:59"
    date-expires "2011-08-08 23:59:59"
    when
        $pointDomain : PointDomain(billThisMonth >= 3)
    then
        $pointDomain.setPoint($pointDomain.getPoint()+$pointDomain.getBillThisMonth()/3*30);
        $pointDomain.recordPointLog($pointDomain.getUserName(),"billThisMonthPoint");
end

rule buyMoneyPoint
    // 当月购物总金额100以上，每100元赠送10分
    salience 98
    lock-on-active true
    when
        $pointDomain : PointDomain(buyMoney >= 100)
    then
        $pointDomain.setPoint($pointDomain.getPoint()+ (int)$pointDomain.getBuyMoney()/100 * 10);
        $pointDomain.recordPointLog($pointDomain.getUserName(),"buyMoneyPoint");
end

rule buyNumsPoint
    // 当月购物次数5次以上，每五次赠送50分
    salience 97
    lock-on-active true
    when
        $pointDomain : PointDomain(buyNums >= 5)
    then
        $pointDomain.setPoint($pointDomain.getPoint()+$pointDomain.getBuyNums()/5 * 50);
        $pointDomain.recordPointLog($pointDomain.getUserName(),"buyNumsPoint");
end

rule allFitPoint
    // 特别的，如果全部满足了要求，则额外奖励100分
    salience 96
    lock-on-active true
    when
        $pointDomain:PointDomain(buyNums >= 5 && billThisMonth >= 3 && buyMoney >= 100)
    then
        $pointDomain.setPoint($pointDomain.getPoint()+ 100);
        $pointDomain.recordPointLog($pointDomain.getUserName(),"allFitPoint");
end

subpoint.drl 与上一篇相同，请参见上一篇，此处省略篇幅略

测试代码

Test

package com.drools.demo.point;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;


public class Test {

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        PointRuleEngine pointRuleEngine = new PointRuleEngineImpl();
        boolean isStart = false;
        while(true){
            InputStream is = System.in;
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String input = br.readLine();

            if (null != input && "s".equals(input)){
                System.out.println("初始化规则引擎...");
                pointRuleEngine.initEngine();
                isStart = true;
                System.out.println("初始化规则引擎结束.");
            } else if ("e".equals(input)){
                if (!isStart) {
                    System.out.println("需要输入s启动");
                } else {
                    final PointDomain pointDomain = new PointDomain();
                    pointDomain.setUserName("hello kity");
                    pointDomain.setBackMondy(100d);
                    pointDomain.setBuyMoney(500d);
                    pointDomain.setBackNums(1);
                    pointDomain.setBuyNums(5);
                    pointDomain.setBillThisMonth(5);
                    pointDomain.setBirthDay(true);
                    pointDomain.setPoint(0l);

                    pointRuleEngine.executeRuleEngine(pointDomain);

                    System.out.println("执行完毕BillThisMonth："+pointDomain.getBillThisMonth());
                    System.out.println("执行完毕BuyMoney："+pointDomain.getBuyMoney());
                    System.out.println("执行完毕BuyNums："+pointDomain.getBuyNums());

                    System.out.println("执行完毕规则引擎决定发送积分："+pointDomain.getPoint());
                }
            } else if ("r".equals(input)){
                System.out.println("刷新规则文件...");
                pointRuleEngine.refreshEnginRule();
                isStart = true;
                System.out.println("刷新规则文件结束.");
            } else if ("q".equals(input)) {
                System.exit(0);
            }
        }
    }

}