add custom event listener in springboot code analysis

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/AbstractEventMulticaster.java

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+package com.example.springboot.source.code.analysis.event;
+
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:20 下午
+ */
+
+
+// 抽象的事件广播器
+public abstract class AbstractEventMulticaster implements EventMulticaster {
+
+    // 事件监听器列表
+    private List<WeatherListener> listenerList = new CopyOnWriteArrayList<>();
+
+    @Override
+    public void multicastEvent(WeatherEvent event) {
+        // 广播所有事件监听器
+        listenerList.forEach(listener -> {
+            doStart();
+            // 触发
+            listener.onWeatherEvent(event);
+            doEnd();
+        });
+    }
+
+    // 添加事件监听器
+    @Override
+    public void addListener(WeatherListener listener) {
+        listenerList.add(listener);
+    }
+
+    // 删除事件监听器
+    @Override
+    public void removeListener(WeatherListener listener) {
+        listenerList.remove(listener);
+    }
+
+
+    // 模版方法
+    abstract void doStart();
+
+    abstract void doEnd();
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/EventMulticaster.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:04 下午
+ */
+
+// 事件广播器
+public interface EventMulticaster {
+
+    // 广播事件
+    void multicastEvent(WeatherEvent event);
+
+    // 添加监听器
+    void addListener(WeatherListener listener);
+
+    // 删除监听器
+    void removeListener(WeatherListener listener);
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/RainEvent.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 2:52 下午
+ */
+
+// 下雨事件
+public class RainEvent extends WeatherEvent {
+
+    @Override
+    public String getWeather() {
+        return "rain";
+    }
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/RainListener.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:00 下午
+ */
+
+
+// 下雨监听器
+public class RainListener implements WeatherListener {
+
+    @Override
+    public void onWeatherEvent(WeatherEvent event) {
+        if (event instanceof RainEvent) {
+            System.out.println("rain event ..." + event.getWeather());
+        }
+    }
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/SnowEvent.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 2:51 下午
+ */
+
+// 下雪事件
+public class SnowEvent extends WeatherEvent {
+
+    @Override
+    public String getWeather() {
+        return "snow";
+    }
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/SnowListener.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:02 下午
+ */
+
+// 下雪监听器
+public class SnowListener implements WeatherListener {
+
+    @Override
+    public void onWeatherEvent(WeatherEvent event) {
+        if (event instanceof SnowEvent) {
+            System.out.println("snow event.." + event.getWeather());
+        }
+    }
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/Test.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:29 下午
+ */
+
+
+public class Test {
+
+    public static void main(String[] args) {
+        // 创建事件广播器
+        WeatherEventMulticaster multicaster = new WeatherEventMulticaster();
+
+        // 添加事件监听器
+        WeatherListener listener1 = new SnowListener();
+        WeatherListener listener2 = new RainListener();
+        multicaster.addListener(listener1);
+        multicaster.addListener(listener2);
+
+        // 广播事件
+        WeatherEvent event1 = new RainEvent();
+        WeatherEvent event2 = new SnowEvent();
+        multicaster.multicastEvent(event1);
+        multicaster.multicastEvent(event2);
+    }
+
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/WeatherEvent.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 2:50 下午
+ */
+
+
+// 天气事件抽象类
+public abstract class WeatherEvent {
+
+    // 获取当前天气的事件
+    public abstract String getWeather();
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/WeatherEventMulticaster.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 3:27 下午
+ */
+
+// 天气事件广播器
+public class WeatherEventMulticaster extends AbstractEventMulticaster {
+
+    @Override
+    public void doStart() {
+        System.out.println("multicaster event begin ...");
+    }
+
+    @Override
+    public void doEnd() {
+        System.out.println("multicaster evnet end ....");
+    }
+}

springboot-source-code-analysis/src/main/java/com/example/springboot/source/code/analysis/event/WeatherListener.java

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+package com.example.springboot.source.code.analysis.event;
+
+/**
+ * Created by ipipman on 2021/8/3.
+ *
+ * @version V1.0
+ * @Package com.example.springboot.source.code.analysis.event
+ * @Description: (用一句话描述该文件做什么)
+ * @date 2021/8/3 2:58 下午
+ */
+
+// 天气监听器
+public interface WeatherListener {
+
+    // 监听天气事件
+    void onWeatherEvent(WeatherEvent event);
+}