小傅哥 | 重学 Java 设计模式：实战观察者模式「模拟类似小客车指标摇号过程，监听消息通知用户中签场景」

.gitignore

@@ -28,3 +28,6 @@
 /itstack-demo-design-16-02/itstack-demo-design-16-02.iml
 /itstack-demo-design-16-01/itstack-demo-design-16-01.iml
 /itstack-demo-design-17-00/itstack-demo-design-17-00.iml
+/itstack-demo-design-18-02/itstack-demo-design-18-02.iml
+/itstack-demo-design-18-01/itstack-demo-design-18-01.iml
+/itstack-demo-design-18-00/itstack-demo-design-18-00.iml

README.md

@@ -24,4 +24,5 @@
 - [`2. 重学 Java 设计模式：实战命令模式「模拟高档餐厅八大菜系，小二点单厨师烹饪场景」`](https://bugstack.cn/itstack-demo-design/2020/06/21/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E5%91%BD%E4%BB%A4%E6%A8%A1%E5%BC%8F.html)
 - [`3. 重学 Java 设计模式：实战迭代器模式「模拟公司组织架构树结构关系，深度迭代遍历人员信息输出场景」`](https://bugstack.cn/itstack-demo-design/2020/06/23/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E8%BF%AD%E4%BB%A3%E5%99%A8%E6%A8%A1%E5%BC%8F.html)
 - [`4. 重学 Java 设计模式：实战中介者模式「按照Mybaits原理手写ORM框架，给JDBC方式操作数据库增加中介者场景」`](https://bugstack.cn/itstack-demo-design/2020/06/27/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E4%B8%AD%E4%BB%8B%E8%80%85%E6%A8%A1%E5%BC%8F.html)
-- [`5. 重学 Java 设计模式：实战备忘录模式「模拟互联网系统上线过程中，配置文件回滚场景」`](https://bugstack.cn/itstack-demo-design/2020/06/28/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E5%A4%87%E5%BF%98%E5%BD%95%E6%A8%A1%E5%BC%8F.html)
\ No newline at end of file
+- [`5. 重学 Java 设计模式：实战备忘录模式「模拟互联网系统上线过程中，配置文件回滚场景」`](https://bugstack.cn/itstack-demo-design/2020/06/28/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E5%A4%87%E5%BF%98%E5%BD%95%E6%A8%A1%E5%BC%8F.html)
+- [`6. 重学 Java 设计模式：实战观察者模式「模拟类似小客车指标摇号过程，监听消息通知用户中签场景」`](https://bugstack.cn/itstack-demo-design/2020/06/30/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E8%A7%82%E5%AF%9F%E8%80%85%E6%A8%A1%E5%BC%8F.html)
\ No newline at end of file

itstack-demo-design-18-00/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>itstack-demo-design</artifactId>
+        <groupId>org.itstack</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>itstack-demo-design-18-00</artifactId>
+
+
+</project>
\ No newline at end of file

itstack-demo-design-18-00/src/main/java/org/itstack/demo/design/MinibusTargetService.java

+package org.itstack.demo.design;
+
+/**
+ * 小客车指标调控服务
+ */
+public class MinibusTargetService {
+
+    /**
+     * 模拟摇号，但不是摇号算法
+     *
+     * @param uId 用户编号
+     * @return 结果
+     */
+    public String lottery(String uId) {
+        return Math.abs(uId.hashCode()) % 2 == 0 ? "恭喜你，编码".concat(uId).concat("在本次摇号中签") : "很遗憾，编码".concat(uId).concat("在本次摇号未中签或摇号资格已过期");
+    }
+
+}

itstack-demo-design-18-01/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>itstack-demo-design</artifactId>
+        <groupId>org.itstack</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>itstack-demo-design-18-01</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>org.itstack</groupId>
+            <artifactId>itstack-demo-design-18-00</artifactId>
+            <version>1.0-SNAPSHOT</version>
+            <scope>compile</scope>
+        </dependency>
+    </dependencies>
+
+
+</project>
\ No newline at end of file

itstack-demo-design-18-01/src/main/java/org/itstack/demo/design/LotteryResult.java

+package org.itstack.demo.design;
+
+import java.util.Date;
+
+public class LotteryResult {
+
+    private String uId;    // 用户ID
+    private String msg;    // 摇号信息
+    private Date dateTime; // 业务时间
+
+    public LotteryResult(String uId, String msg, Date dateTime) {
+        this.uId = uId;
+        this.msg = msg;
+        this.dateTime = dateTime;
+    }
+
+    public String getuId() {
+        return uId;
+    }
+
+    public void setuId(String uId) {
+        this.uId = uId;
+    }
+
+    public String getMsg() {
+        return msg;
+    }
+
+    public void setMsg(String msg) {
+        this.msg = msg;
+    }
+
+    public Date getDateTime() {
+        return dateTime;
+    }
+
+    public void setDateTime(Date dateTime) {
+        this.dateTime = dateTime;
+    }
+}

itstack-demo-design-18-01/src/main/java/org/itstack/demo/design/LotteryService.java

+package org.itstack.demo.design;
+
+public interface LotteryService {
+
+    LotteryResult doDraw(String uId);
+
+}

itstack-demo-design-18-01/src/main/java/org/itstack/demo/design/LotteryServiceImpl.java

+package org.itstack.demo.design;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Date;
+
+public class LotteryServiceImpl implements LotteryService {
+
+    private Logger logger = LoggerFactory.getLogger(LotteryServiceImpl.class);
+
+    private MinibusTargetService minibusTargetService = new MinibusTargetService();
+
+    public LotteryResult doDraw(String uId) {
+        // 摇号
+        String lottery = minibusTargetService.lottery(uId);
+        // 发短信
+        logger.info("给用户 {} 发送短信通知(短信)：{}", uId, lottery);
+        // 发MQ消息
+        logger.info("记录用户 {} 摇号结果(MQ)：{}", uId, lottery);
+        // 结果
+        return new LotteryResult(uId, lottery, new Date());
+    }
+
+}

itstack-demo-design-18-01/src/test/java/org/itstack/demo/design/ApiTest.java

+package org.itstack.demo.design;
+
+import com.alibaba.fastjson.JSON;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ApiTest {
+
+    private Logger logger = LoggerFactory.getLogger(ApiTest.class);
+
+    @Test
+    public void test() {
+        LotteryService lotteryService = new LotteryServiceImpl();
+        LotteryResult result = lotteryService.doDraw("2765789109876");
+        logger.info("测试结果：{}", JSON.toJSONString(result));
+    }
+
+}

itstack-demo-design-18-02/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>itstack-demo-design</artifactId>
+        <groupId>org.itstack</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>itstack-demo-design-18-02</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>org.itstack</groupId>
+            <artifactId>itstack-demo-design-18-00</artifactId>
+            <version>1.0-SNAPSHOT</version>
+            <scope>compile</scope>
+        </dependency>
+    </dependencies>
+
+
+</project>
\ No newline at end of file

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/LotteryResult.java

+package org.itstack.demo.design;
+
+import java.util.Date;
+
+public class LotteryResult {
+
+    private String uId;    // 用户ID
+    private String msg;    // 摇号信息
+    private Date dateTime; // 业务时间
+
+    public LotteryResult(String uId, String msg, Date dateTime) {
+        this.uId = uId;
+        this.msg = msg;
+        this.dateTime = dateTime;
+    }
+
+    public String getuId() {
+        return uId;
+    }
+
+    public void setuId(String uId) {
+        this.uId = uId;
+    }
+
+    public String getMsg() {
+        return msg;
+    }
+
+    public void setMsg(String msg) {
+        this.msg = msg;
+    }
+
+    public Date getDateTime() {
+        return dateTime;
+    }
+
+    public void setDateTime(Date dateTime) {
+        this.dateTime = dateTime;
+    }
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/LotteryService.java

+package org.itstack.demo.design;
+
+import org.itstack.demo.design.event.EventManager;
+import org.itstack.demo.design.event.listener.MQEventListener;
+import org.itstack.demo.design.event.listener.MessageEventListener;
+
+public abstract class LotteryService {
+
+    private EventManager eventManager;
+
+    public LotteryService() {
+        eventManager = new EventManager(EventManager.EventType.MQ, EventManager.EventType.Message);
+        eventManager.subscribe(EventManager.EventType.MQ, new MQEventListener());
+        eventManager.subscribe(EventManager.EventType.Message, new MessageEventListener());
+    }
+
+    public LotteryResult draw(String uId) {
+        LotteryResult lotteryResult = doDraw(uId);
+        // 需要什么通知就给调用什么方法
+        eventManager.notify(EventManager.EventType.MQ, lotteryResult);
+        eventManager.notify(EventManager.EventType.Message, lotteryResult);
+        return lotteryResult;
+    }
+
+    protected abstract LotteryResult doDraw(String uId);
+
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/LotteryServiceImpl.java

+package org.itstack.demo.design;
+
+import java.util.Date;
+
+public class LotteryServiceImpl extends LotteryService {
+
+    private MinibusTargetService minibusTargetService = new MinibusTargetService();
+
+    @Override
+    protected LotteryResult doDraw(String uId) {
+        // 摇号
+        String lottery = minibusTargetService.lottery(uId);
+        // 结果
+        return new LotteryResult(uId, lottery, new Date());
+    }
+
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/event/EventManager.java

+package org.itstack.demo.design.event;
+
+import org.itstack.demo.design.LotteryResult;
+import org.itstack.demo.design.event.listener.EventListener;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class EventManager {
+
+    Map<Enum<EventType>, List<EventListener>> listeners = new HashMap<>();
+
+    public EventManager(Enum<EventType>... operations) {
+        for (Enum<EventType> operation : operations) {
+            this.listeners.put(operation, new ArrayList<>());
+        }
+    }
+
+    public enum EventType {
+        MQ, Message
+    }
+
+    /**
+     * 订阅
+     * @param eventType 事件类型
+     * @param listener  监听
+     */
+    public void subscribe(Enum<EventType> eventType, EventListener listener) {
+        List<EventListener> users = listeners.get(eventType);
+        users.add(listener);
+    }
+
+    /**
+     * 取消订阅
+     * @param eventType 事件类型
+     * @param listener  监听
+     */
+    public void unsubscribe(Enum<EventType> eventType, EventListener listener) {
+        List<EventListener> users = listeners.get(eventType);
+        users.remove(listener);
+    }
+
+    /**
+     * 通知
+     * @param eventType 事件类型
+     * @param result    结果
+     */
+    public void notify(Enum<EventType> eventType, LotteryResult result) {
+        List<EventListener> users = listeners.get(eventType);
+        for (EventListener listener : users) {
+            listener.doEvent(result);
+        }
+    }
+
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/event/listener/EventListener.java

+package org.itstack.demo.design.event.listener;
+
+import org.itstack.demo.design.LotteryResult;
+
+public interface EventListener {
+
+    void doEvent(LotteryResult result);
+
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/event/listener/MQEventListener.java

+package org.itstack.demo.design.event.listener;
+
+import org.itstack.demo.design.LotteryResult;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MQEventListener implements EventListener {
+
+    private Logger logger = LoggerFactory.getLogger(MQEventListener.class);
+
+    @Override
+    public void doEvent(LotteryResult result) {
+        logger.info("记录用户 {} 摇号结果(MQ)：{}", result.getuId(), result.getMsg());
+    }
+
+}

itstack-demo-design-18-02/src/main/java/org/itstack/demo/design/event/listener/MessageEventListener.java

+package org.itstack.demo.design.event.listener;
+
+import org.itstack.demo.design.LotteryResult;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class MessageEventListener implements EventListener {
+
+    private Logger logger = LoggerFactory.getLogger(MessageEventListener.class);
+
+    @Override
+    public void doEvent(LotteryResult result) {
+        logger.info("给用户 {} 发送短信通知(短信)：{}", result.getuId(), result.getMsg());
+    }
+
+}
\ No newline at end of file

itstack-demo-design-18-02/src/test/java/org/itstack/demo/design/test/ApiTest.java

+package org.itstack.demo.design.test;
+
+import com.alibaba.fastjson.JSON;
+import org.itstack.demo.design.LotteryResult;
+import org.itstack.demo.design.LotteryService;
+import org.itstack.demo.design.LotteryServiceImpl;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ApiTest {
+
+    private Logger logger = LoggerFactory.getLogger(ApiTest.class);
+
+    @Test
+    public void test() {
+        LotteryService lotteryService = new LotteryServiceImpl();
+        LotteryResult result = lotteryService.draw("2765789109876");
+        logger.info("测试结果：{}", JSON.toJSONString(result));
+    }
+
+}

pom.xml

@@ -49,6 +49,9 @@
         <module>itstack-demo-design-16-01</module>
         <module>itstack-demo-design-16-02</module>
         <module>itstack-demo-design-17-00</module>
+        <module>itstack-demo-design-18-00</module>
+        <module>itstack-demo-design-18-01</module>
+        <module>itstack-demo-design-18-02</module>
     </modules>
 
     <dependencies>