Facade Design pattern

README.md

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-# DesignPatternsJava9
-This repo consists Gang of Four Design patterns code on Java 9. Each branch in the repository has code of 1 design pattern. Switch repository to try out different design patterns.
+# What is Facade Design Pattern 
+* Facade pattern adds an interface to existing system or group of sub systems to hide its complexities
+* This pattern involves a single class which provides interface with simplified methods required by client and delegates calls to methods of existing system classes.
+
+## Diagram
+![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/facade-pattern/diagrams/4_3%20Facade%20class%20diagram.jpeg "Diagram")
+
+![Diagram](https://github.com/premaseem/DesignPatternsJava9/blob/facade-pattern/diagrams/4_3%20facade%20sequence.png "Diagram")
+
+### When to use Facade Design Pattern 
+When application needs a simplified interface to the overall functionality of a complex subsystem.
+
+### Learn Design Patterns with Java by Aseem Jain
+This repository contains working project code used in video Course by Packt Publication with title "Learn Design Patterns with Java " authored by "Aseem Jain".
+
+### Course link: 
+https://www.packtpub.com/application-development/learn-design-patterns-java-9-video
+
+### ![ http://in.linkedin.com/in/premaseem](https://github.com/premaseem/DesignPatternsJava9/blob/master/linkedin.png "http://in.linkedin.com/in/premaseem") Profile:  http://in.linkedin.com/in/premaseem
+
+### Authors blog on design patterns:
+https://premaseem.wordpress.com/category/computers/design-patterns/
+
+### Software Design pattern community face book page:
+https://www.facebook.com/DesignPatternGuru/
+
+### Note: 
+* This code base will work on Java 9 and above versions. 
+* `diagrams` folders carry UML diagrams.
+* `pattern` folder has code of primary example. 
+* `patternBonus` folder has code of secondary or bonus example.

pattern/src/me/premaseem/Client.java

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+package me.premaseem;
+
+import me.premaseem.remotes.MasterRemoteFacade;
+import me.premaseem.remotes.SetTopBoxRemote;
+import me.premaseem.remotes.SoundSystemRemote;
+import me.premaseem.remotes.TVRemote;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class Client {
+    public static void main (String[] args) {
+        System.out.println("Master Remote Facade ");
+
+        // decoupled systems from client and moved to facade
+        MasterRemoteFacade masterRemoteFacade = new MasterRemoteFacade();
+
+        // Facade simplified code and reduced complexity
+        masterRemoteFacade.turnOn();
+        masterRemoteFacade.turnOFF();
+
+//        // Turning ON requires several calls
+//        tvRemote.trunOn();
+//        soundSystemRemote.trunOn();
+//        setTopBoxRemote.trunOn();
+//
+//        // Turning OFF requires several calls
+//        tvRemote.trunOn();
+//        soundSystemRemote.trunOn();
+//        setTopBoxRemote.trunOn();
+    }
+}

pattern/src/me/premaseem/remotes/MasterRemoteFacade.java

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+package me.premaseem.remotes;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class MasterRemoteFacade {
+
+    // sub system is de coupled from client
+    private TVRemote tvRemote;
+    private SoundSystemRemote soundSystemRemote;
+    private SetTopBoxRemote setTopBoxRemote;
+
+    public MasterRemoteFacade(){
+         tvRemote = new TVRemote();
+         soundSystemRemote = new SoundSystemRemote();
+         setTopBoxRemote = new SetTopBoxRemote();
+    }
+
+    // Master turn on takes care of all sub systems
+    public void turnOn(){
+        System.out.println();
+        System.out.println("Turning ON all sub systems");
+        tvRemote.trunOn();
+        soundSystemRemote.trunOn();
+        setTopBoxRemote.trunOn();
+    }
+
+    // Master turn off takes care of all sub systems
+    public void turnOFF(){
+        System.out.println();
+        System.out.println("Turning OFF all sub systems");
+        tvRemote.trunOff();
+        soundSystemRemote.trunOff();
+        setTopBoxRemote.trunOff();
+    }
+}

pattern/src/me/premaseem/remotes/SetTopBoxRemote.java

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+package me.premaseem.remotes;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class SetTopBoxRemote {
+
+    public void trunOn(){
+        System.out.println("Set Top box power turn ON ");
+    }
+
+    public void trunOff(){
+        System.out.println("Set Top box power turn OFF ");
+    }
+}

pattern/src/me/premaseem/remotes/SoundSystemRemote.java

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+package me.premaseem.remotes;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class SoundSystemRemote {
+
+    public void trunOn(){
+        System.out.println("Sound System power turn ON ");
+    }
+
+    public void trunOff(){
+        System.out.println("Sound System power turn OFF ");
+    }
+}

pattern/src/me/premaseem/remotes/TVRemote.java

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+package me.premaseem.remotes;
+
+/*
+@author: Aseem Jain
+@title: Design Patterns with Java 9
+@link: https://premaseem.wordpress.com/category/computers/design-patterns/
+*/
+public class TVRemote {
+
+    public void trunOn(){
+        System.out.println("TV power turn ON ");
+    }
+
+    public void trunOff(){
+        System.out.println("TV power turn OFF ");
+    }
+}

patternBonus/src/me/premaseem/facade/ClientForEntertainmentUnitFacade.java

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+package me.premaseem.facade;
+
+import java.util.Scanner;
+
+public class ClientForEntertainmentUnitFacade {
+
+    public static void main (String[] args) {
+        Scanner scan = new Scanner(System.in);
+        int repeatRunFlag = 1;
+
+
+        System.out.println("This is Facade Pattern example which provides a simple interface " +
+                "for the client to play a movie me entertainment unit " +
+                "(simplifies the setup process of entertainment unit) ");
+
+        EntertainmentFacade entertainmentFacade = new EntertainmentFacade();
+        while (repeatRunFlag == 1) {
+            System.out.println("What would you like to do with your entertainment unit today ");
+            System.out.println(" Press 1 for movie");
+            System.out.println(" Press 2 for music");
+            System.out.println(" Press 3 for game ");
+            int entType = scan.nextInt();
+            System.out.println("Please enter the name ");
+            String name = scan.next();
+
+
+            switch (entType) {
+                case 1:
+                    entertainmentFacade.playMovie(name);
+                    break;
+                case 2:
+                    entertainmentFacade.playMusic(name);
+                    break;
+                case 3:
+                    entertainmentFacade.playGame(name);
+                    break;
+            }
+
+            System.out.println("Press 1 for more entertainment and 0 for EXIT .... ");
+            try {
+                repeatRunFlag = scan.nextInt();
+            } catch (Exception e) {
+                repeatRunFlag = 0;
+            } finally {
+                entertainmentFacade.masterPowerOff();
+            }
+
+        }
+    }
+}

patternBonus/src/me/premaseem/facade/EntertainmentDevice.java

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+package me.premaseem.facade;
+
+public class EntertainmentDevice {
+
+}
+
+class Nexus {
+	public void downloadmedia(String name) {
+		System.out.println("Searching the media ");
+		System.out.println("Making online payment ");
+		System.out.println("downloaded from Nexus " + name);
+	}
+}
+
+class Amplifier {
+
+	void powerOn() {
+		System.out.println("Power on Amplifier");
+	}
+
+	void powerOff() {
+		System.out.println("power Off Amplifer ");
+	}
+
+	void attachAmplifierForMusic() {
+		System.out.println("Attaching music amplification");
+	}
+
+	void attachAmplifierForHomeTheater() {
+		System.out.println("Attaching movie amplification ");
+	}
+}
+
+class Projector {
+
+	void powerOn() {
+		System.out.println("Power on Projector");
+	}
+
+	void powerOff() {
+		System.out.println("power Off Projector ");
+	}
+
+	void adjustProjectorForMovie() {
+		System.out.println("Attaching home theater mode");
+	}
+
+	void adjustProjectorForGame() {
+		System.out.println("Attaching game console ");
+	}
+}

patternBonus/src/me/premaseem/facade/EntertainmentFacade.java

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+package me.premaseem.facade;
+
+public class EntertainmentFacade {
+
+	Nexus nexus = new Nexus();
+	Amplifier amplifier = new Amplifier();
+	Projector projector = new Projector();
+
+	public void playMovie(String name) {
+		nexus.downloadmedia(name);
+		masterPowerOn();
+		amplifier.attachAmplifierForHomeTheater();
+		projector.adjustProjectorForMovie();
+	}
+
+	public void playMusic(String name) {
+		nexus.downloadmedia(name);
+		amplifier.powerOn();
+		amplifier.attachAmplifierForMusic();
+	}
+
+	public void playGame(String name) {
+		nexus.downloadmedia(name);
+		masterPowerOn();
+		amplifier.attachAmplifierForMusic();
+		projector.adjustProjectorForGame();
+	}
+
+	public void masterPowerOff() {
+		amplifier.powerOff();
+		projector.powerOff();
+	}
+
+	public void masterPowerOn() {
+		amplifier.powerOn();
+		projector.powerOn();
+	}
+
+}