完成观察者模式

Author: chrischen789

src/main/java/com/chrischen/designpattern/observer/ob/CurrentConditionsDisplay.java

@@ -0,0 +1,38 @@
+package com.chrischen.designpattern.observer.ob;
+
+import com.chrischen.designpattern.observer.subject.Subject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class CurrentConditionsDisplay implements Observer, DisplayElement {
+
+    private static final Logger log = LoggerFactory.getLogger(CurrentConditionsDisplay.class);
+
+    private Subject weatherData;
+
+    private float temp;
+
+    private float humidity;
+
+    private float pressure;
+
+    public CurrentConditionsDisplay(Subject weatherData) {
+        this.weatherData = weatherData;
+        weatherData.registerObserver(this);
+    }
+
+    @Override
+    public void update(float temp, float humidity, float pressure) {
+        this.temp = temp;
+        this.humidity = humidity;
+        this.pressure = humidity;
+        this.display();
+    }
+
+    @Override
+    public void display() {
+        log.info("今天的天气情况，温度：{}，湿度：{}，气压：{}", this.temp, this.humidity, this.pressure);
+    }
+
+
+}

src/main/java/com/chrischen/designpattern/observer/ob/DisplayElement.java

@@ -0,0 +1,7 @@
+package com.chrischen.designpattern.observer.ob;
+
+public interface DisplayElement {
+
+    void display();
+
+}

src/main/java/com/chrischen/designpattern/observer/ob/Observer.java

@@ -0,0 +1,7 @@
+package com.chrischen.designpattern.observer.ob;
+
+public interface Observer {
+
+    void update(float temp, float humidity, float pressure);
+
+}

src/main/java/com/chrischen/designpattern/observer/subject/Subject.java

@@ -0,0 +1,13 @@
+package com.chrischen.designpattern.observer.subject;
+
+import com.chrischen.designpattern.observer.ob.Observer;
+
+public interface Subject {
+
+    void registerObserver(Observer observer);
+
+    void removeObserver(Observer observer);
+
+    void notifyObserver();
+
+}

src/main/java/com/chrischen/designpattern/observer/subject/WeatherData.java

@@ -0,0 +1,57 @@
+package com.chrischen.designpattern.observer.subject;
+
+import com.chrischen.designpattern.observer.ob.Observer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class WeatherData implements Subject {
+
+    private List observers = new ArrayList();
+
+    private float temperature;
+
+    private float humidity;
+
+    private float pressure;
+
+    public void setTemperature(float temperature) {
+        this.temperature = temperature;
+    }
+
+    public void setHumidity(float humidity) {
+        this.humidity = humidity;
+    }
+
+    public void setPressure(float pressure) {
+        this.pressure = pressure;
+    }
+
+    @Override
+    public void registerObserver(Observer observer) {
+        observers.add(observer);
+    }
+
+    @Override
+    public void removeObserver(Observer observer) {
+        int target = observers.indexOf(observer);
+        if (target > -1) {
+            observers.remove(target);
+        }
+    }
+
+    @Override
+    public void notifyObserver() {
+        for (int i = 0; i < observers.size(); i++) {
+            Observer observer = (Observer) observers.get(i);
+            observer.update(this.temperature, this.humidity, this.pressure);
+        }
+    }
+
+    public void measurementsChanged(float temperature, float humidity, float pressure) {
+        this.temperature = temperature;
+        this.humidity = humidity;
+        this.pressure = pressure;
+        this.notifyObserver();
+    }
+}

src/main/java/com/chrischen/designpattern/strategy/character/Character.java

@@ -17,7 +17,6 @@ public void fight() {
     }
 
     public void setWeapon(WeaponBehavior weapon) {
-
         this.weapon = weapon;
         log.info("change now weapon!");
     }

src/main/java/com/chrischen/designpattern/strategy/weapon/BowAndArrowBehavior.java

@@ -9,6 +9,6 @@ public class BowAndArrowBehavior implements WeaponBehavior {
 
     @Override
     public void useWeapon() {
-        log.info("noe use bow and arrow to hit enemy");
+        log.info("now use bow and arrow to hit enemy");
     }
 }

src/test/java/com/chrischen/designpattern/strategy/ObserverTest.java

@@ -0,0 +1,25 @@
+package com.chrischen.designpattern.strategy;
+
+import com.chrischen.designpattern.observer.ob.CurrentConditionsDisplay;
+import com.chrischen.designpattern.observer.subject.WeatherData;
+import org.junit.Test;
+
+
+public class ObserverTest {
+
+    @Test
+    public void test() {
+        WeatherData weatherData = new WeatherData();
+
+        CurrentConditionsDisplay currentConditionsDisplay = new CurrentConditionsDisplay(weatherData);
+
+        weatherData.measurementsChanged(24, 51, 1.1f);
+
+        weatherData.removeObserver(currentConditionsDisplay);
+        weatherData.measurementsChanged(24, 51, 1.1f);
+
+        weatherData.registerObserver(currentConditionsDisplay);
+        weatherData.measurementsChanged(22, 53, 1.0f);
+    }
+
+}

src/test/java/com/chrischen/designpattern/strategy/StrategyTest.java

@@ -11,7 +11,7 @@ public class StrategyTest {
     @Test
     public void initCharacter() {
         Character king = new King();
-        king.startGame();
+//        king.startGame();
         king.fight();
         king.setWeapon(new SwordBehavior());
         king.fight();