- refactored the dir

- Observer pattern

Author: Zaidtech

pom.xml

@@ -0,0 +1,17 @@
+<?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">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>designPattern</groupId>
+    <artifactId>DesignPatterns</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>24</maven.compiler.source>
+        <maven.compiler.target>24</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    
+</project>

src/main/java/designPattern/Main.java

@@ -1,6 +1,6 @@
 package designPattern;
 
-import singleton.*;
+import designPattern.creational.singleton.*;
 
 import java.lang.reflect.*;
 

src/main/java/designPattern/behavioural/observer/Main.java

@@ -0,0 +1,11 @@
+package designPattern.behavioural.observer;
+
+public class Main {
+    public static void main(String[] args) {
+        YTChannel ytChannel = new YTChannel();
+        Subscriber subscriber = new Subscriber();
+
+        ytChannel.register(subscriber);
+        ytChannel.notifyObservers("Welcome to YT Channel:  ");
+    }
+}

src/main/java/designPattern/behavioural/observer/Notes

@@ -0,0 +1,2 @@
+1. Behavioural Design pattern: Tells about how will objects interact with each other
+2. In this if the subject chanegs the state all the dependent objects notified the change.

src/main/java/designPattern/behavioural/observer/Observer.java

@@ -0,0 +1,5 @@
+package designPattern.behavioural.observer;
+
+public interface Observer {
+    void getNotified(String message);
+}

src/main/java/designPattern/behavioural/observer/Subject.java

@@ -0,0 +1,8 @@
+package designPattern.behavioural.observer;
+
+public interface Subject {
+    void register(Observer observer);
+    void unregister(Observer observer);
+
+    void notifyObservers(String message);
+}

src/main/java/designPattern/behavioural/observer/Subscriber.java

@@ -0,0 +1,8 @@
+package designPattern.behavioural.observer;
+
+public class Subscriber implements Observer {
+    @Override
+    public void getNotified(String message) {
+        System.out.println("Notified about a change in the subject"+message);
+    }
+}

src/main/java/designPattern/behavioural/observer/YTChannel.java

@@ -0,0 +1,25 @@
+package designPattern.behavioural.observer;
+
+import java.util.*;
+
+public class YTChannel implements Subject {
+    private String name;
+    private List<Observer> observers = new ArrayList<>();
+
+    @Override
+    public void register(Observer observer) {
+        observers.add(observer);
+    }
+
+    @Override
+    public void unregister(Observer observer) {
+        observers.remove(observer);
+    }
+
+    @Override
+    public void notifyObservers(String message) {
+        for(Observer observer : observers) {
+            observer.getNotified(message);
+        }
+    }
+}

…ractFactory/AbstractEmployeeFactory.java …ractFactory/AbstractEmployeeFactory.javasrc/main/java/designPattern/abstractFactory/AbstractEmployeeFactory.java renamed to src/main/java/designPattern/creational/abstractFactory/AbstractEmployeeFactory.java src/main/java/designPattern/abstractFactory/AbstractEmployeeFactory.java renamed to src/main/java/designPattern/creational/abstractFactory/AbstractEmployeeFactory.java

@@ -1,4 +1,4 @@
-package designPattern.abstractFactory;
+package designPattern.creational.abstractFactory;
 
 public abstract class AbstractEmployeeFactory {
     public abstract IEmployee getEmployee();

…ern/abstractFactory/EmployeeFactory.java …nal/abstractFactory/EmployeeFactory.javasrc/main/java/designPattern/abstractFactory/EmployeeFactory.java renamed to src/main/java/designPattern/creational/abstractFactory/EmployeeFactory.java src/main/java/designPattern/abstractFactory/EmployeeFactory.java renamed to src/main/java/designPattern/creational/abstractFactory/EmployeeFactory.java

@@ -1,4 +1,4 @@
-package designPattern.abstractFactory;
+package designPattern.creational.abstractFactory;
 
 public class EmployeeFactory {
     public static IEmployee getEmployee(AbstractEmployeeFactory factory) {