Mediator Pattern

design-pattern/src/Mediator/Application.java

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+package Mediator;
+
+import Mediator.contract.Colleague;
+import Mediator.contract.Mediator;
+
+public class Application {
+
+    public static void main(String[] args) {
+        Mediator mediator = new ChatMediator();
+
+        Colleague colleague1 = new ChatColleague();
+        Colleague colleague2 = new ChatColleague();
+        Colleague colleague3 = new ChatColleague();
+
+        colleague1.join(mediator);
+        colleague2.join(mediator);
+        colleague3.join(mediator);
+
+        colleague1.sendData("AAA");
+        colleague2.sendData("BBB");
+        colleague3.sendData("CCC");
+    }
+}

design-pattern/src/Mediator/ChatColleague.java

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+package Mediator;
+
+import Mediator.contract.Colleague;
+
+public class ChatColleague extends Colleague {
+    @Override
+    public void handle(String data) {
+        System.out.println(this + data);
+    }
+}

design-pattern/src/Mediator/ChatMediator.java

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+package Mediator;
+
+import Mediator.contract.Colleague;
+import Mediator.contract.Mediator;
+
+public class ChatMediator extends Mediator {
+    @Override
+    public void mediate(String data) {
+        for(Colleague colleague: colleagues) {
+            colleague.handle(data);
+        }
+    }
+}

design-pattern/src/Mediator/Mediator

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+Mediator Pattern
+ - M:N 관계를 1:1 로 변경하기

design-pattern/src/Mediator/contract/Colleague.java

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+package Mediator.contract;
+
+public abstract class Colleague {
+
+    private Mediator mediator;
+
+    public boolean join(Mediator mediator) {
+        if(mediator == null) return false;
+        this.mediator = mediator;
+        return mediator.addColleague(this);
+    }
+
+    public void sendData(String data) {
+        if(mediator != null) {
+            mediator.mediate(data);
+        }
+    }
+
+    public abstract void handle(String data);
+}

design-pattern/src/Mediator/contract/Mediator.java

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+package Mediator.contract;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class Mediator {
+
+    protected List<Colleague> colleagues;
+
+    public Mediator() {
+        colleagues = new ArrayList<>();
+    }
+
+    public boolean addColleague(Colleague colleague) {
+        if(colleagues != null) {
+            return colleagues.add(colleague);
+        } else {
+            return false;
+        }
+    }
+
+    public abstract void mediate(String data);
+}