observer Finished

comprehensive/pom.xml

@@ -75,5 +75,15 @@
                 </plugin>
             </plugins>
         </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 </project>

comprehensive/src/main/java/com/luo/observer/simple/Example.java

@@ -0,0 +1,14 @@
+package com.luo.observer.simple;
+
+/**
+ * @author luoxuzheng
+ * @create 2019-09-15 19:39
+ **/
+public class Example {
+
+    public static void main(String[] args) {
+        Subject subject = new SimpleSubject();
+        Observer observer = new SimpleObserver(subject);
+        ((SimpleSubject) subject).setValue(1);
+    }
+}

comprehensive/src/main/java/com/luo/observer/simple/Observer.java

@@ -0,0 +1,16 @@
+package com.luo.observer.simple;
+
+/**
+ * 观察者
+ *
+ * @author luoxuzheng
+ * @create 2019-09-15 19:43
+ **/
+public interface Observer {
+
+    /**
+     * 通知
+     * @param value
+     */
+    void update(Integer value);
+}

comprehensive/src/main/java/com/luo/observer/simple/SimpleObserver.java

@@ -0,0 +1,27 @@
+package com.luo.observer.simple;
+
+/**
+ * @author luoxuzheng
+ * @create 2019-09-15 19:47
+ **/
+public class SimpleObserver implements Observer {
+
+    //通知数据
+    private Integer value;
+    private Subject subject;
+
+    public SimpleObserver(Subject subject) {
+        this.subject = subject;
+        subject.registerObserver(this);
+    }
+
+    @Override
+    public void update(Integer value) {
+        this.value = value;
+        display();
+    }
+
+    public void display() {
+        System.out.println("value:" + value);
+    }
+}

comprehensive/src/main/java/com/luo/observer/simple/SimpleSubject.java

@@ -0,0 +1,42 @@
+package com.luo.observer.simple;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author luoxuzheng
+ * @create 2019-09-15 19:47
+ **/
+public class SimpleSubject implements Subject {
+
+    private List<Observer> observers;
+    private Integer value = 0;
+
+    public SimpleSubject() {
+        this.observers = new ArrayList<>();
+    }
+
+    @Override
+    public void registerObserver(Observer observer) {
+        this.observers.add(observer);
+    }
+
+    @Override
+    public void removeObserver(Observer observer) {
+        int index = this.observers.indexOf(observer);
+        if (index >= 0)
+            this.observers.remove(observer);
+    }
+
+    @Override
+    public void notifyObservers() {
+        for (Observer observer : this.observers) {
+            observer.update(value);
+        }
+    }
+
+    public void setValue(Integer value) {
+        this.value = value;
+        notifyObservers();
+    }
+}

comprehensive/src/main/java/com/luo/observer/simple/Subject.java

@@ -0,0 +1,28 @@
+package com.luo.observer.simple;
+
+/**
+ * 被观察者
+ *
+ * @author luoxuzheng
+ * @create 2019-09-15 19:42
+ **/
+public interface Subject {
+
+    /**
+     * 注册观察者
+     * @param observer
+     */
+    void registerObserver(Observer observer);
+
+    /**
+     * 移除观察者
+     * @param observer
+     */
+    void removeObserver(Observer observer);
+
+    /**
+     * 通知观察者
+     */
+    void notifyObservers();
+
+}

comprehensive/src/main/java/com/luo/observer/simpleobservable/Example.java

@@ -0,0 +1,17 @@
+package com.luo.observer.simpleobservable;
+
+
+import java.util.Observer;
+
+/**
+ * @author luoxuzheng
+ * @create 2019-09-15 19:39
+ **/
+public class Example {
+
+    public static void main(String[] args) {
+        SimpleObservable observable = new SimpleObservable();
+        Observer observer = new SimpleObserver(observable);
+        observable.setValue(1);
+    }
+}

comprehensive/src/main/java/com/luo/observer/simpleobservable/SimpleObservable.java

@@ -0,0 +1,22 @@
+package com.luo.observer.simpleobservable;
+
+import java.util.Observable;
+import java.util.Observer;
+
+/**
+ * @author luoxuzheng
+ * @create 2019-09-15 20:02
+ **/
+public class SimpleObservable extends Observable {
+    private Integer value;
+
+    public void setValue(Integer value){
+        this.value = value;
+        setChanged();
+        notifyObservers(value);
+    }
+
+    public Integer getValue() {
+        return value;
+    }
+}

comprehensive/src/main/java/com/luo/observer/simpleobservable/SimpleObserver.java

@@ -0,0 +1,39 @@
+package com.luo.observer.simpleobservable;
+
+import java.util.Observable;
+import java.util.Observer;
+
+/**
+ * 观察者
+ *
+ * @author luoxuzheng
+ * @create 2019-09-15 20:01
+ **/
+public class SimpleObserver implements Observer {
+    private Integer value;
+    private Observable observable;
+
+    public SimpleObserver(Observable observable) {
+        this.observable = observable;
+        this.observable.addObserver(this);
+    }
+
+    @Override
+    public void update(Observable o, Object arg) {
+
+        //1、被通知
+        this.value = (Integer) arg;
+        display();
+
+        //2、主动拉取
+        if(o instanceof SimpleObservable){
+            this.value = ((SimpleObservable) o).getValue();
+            display();
+        }
+    }
+
+    public void display() {
+        System.out.println("value:" + value);
+    }
+
+}