Optional OfNullable with map

Author: Arpit Aggarwal

src/com/test/design/adapter/AdapterPatternDemo.java

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+package com.test.design.adapter;
+
+public class AdapterPatternDemo {
+	public static void main(String[] args) {
+		AudioPlayer audioPlayer = new AudioPlayer();
+
+		audioPlayer.play("mp3", "beyond the horizon.mp3");
+		audioPlayer.play("mp4", "alone.mp4");
+		audioPlayer.play("vlc", "far far away.vlc");
+		audioPlayer.play("avi", "mind me.avi");
+	}
+}

src/com/test/design/adapter/AdvancedMediaPlayer.java

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+package com.test.design.adapter;
+
+public interface AdvancedMediaPlayer {
+	public void playVlc(String fileName);
+
+	public void playMp4(String fileName);
+}

src/com/test/design/adapter/AudioPlayer.java

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+package com.test.design.adapter;
+
+public class AudioPlayer implements MediaPlayer {
+
+	MediaAdapter mediaAdapter;
+
+	@Override
+	public void play(String audioType, String fileName) {
+
+		// inbuilt support to play mp3 music files
+		if (audioType.equalsIgnoreCase("mp3")) {
+			System.out.println("Playing mp3 file. Name: " + fileName);
+		}
+
+		// mediaAdapter is providing support to play other file formats
+		else if (audioType.equalsIgnoreCase("vlc")
+				|| audioType.equalsIgnoreCase("mp4")) {
+			mediaAdapter = new MediaAdapter(audioType);
+			mediaAdapter.play(audioType, fileName);
+		}
+
+		else {
+			System.out.println("Invalid media. " + audioType
+					+ " format not supported");
+		}
+	}
+}

src/com/test/design/adapter/MediaAdapter.java

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+package com.test.design.adapter;
+
+public class MediaAdapter implements MediaPlayer {
+
+	AdvancedMediaPlayer advancedMusicPlayer;
+
+	public MediaAdapter(String audioType) {
+
+		if (audioType.equalsIgnoreCase("vlc")) {
+			advancedMusicPlayer = new VlcPlayer();
+
+		} else if (audioType.equalsIgnoreCase("mp4")) {
+			advancedMusicPlayer = new Mp4Player();
+		}
+	}
+
+	@Override
+	public void play(String audioType, String fileName) {
+
+		if (audioType.equalsIgnoreCase("vlc")) {
+			advancedMusicPlayer.playVlc(fileName);
+		} else if (audioType.equalsIgnoreCase("mp4")) {
+			advancedMusicPlayer.playMp4(fileName);
+		}
+	}
+}

src/com/test/design/adapter/MediaPlayer.java

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+package com.test.design.adapter;
+
+public interface MediaPlayer {
+	public void play(String audioType, String fileName);
+}

src/com/test/design/adapter/Mp4Player.java

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+package com.test.design.adapter;
+
+public class Mp4Player implements AdvancedMediaPlayer {
+
+	@Override
+	public void playVlc(String fileName) {
+		// do nothing
+	}
+
+	@Override
+	public void playMp4(String fileName) {
+		System.out.println("Playing mp4 file. Name: " + fileName);
+	}
+}

src/com/test/design/adapter/README.txt

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+Adapter Design Pattern is a Structural Design Pattern - Adapter pattern works as a bridge between two incompatible interfaces.
+
+This pattern involves a single class which is responsible to join functionalities of independent 
+or incompatible interfaces. A real life example could be a case of card reader which acts as 
+an adapter between memory card and a laptop. You plugin the memory card into card reader and 
+card reader into the laptop so that memory card can be read via laptop.
+
+Adapter (recognizeable by creational methods taking an instance of different abstract/interface type 
+and returning an implementation of own/another abstract/interface type which decorates/overrides the given instance)
+1). java.util.Arrays#asList()
+2). java.io.InputStreamReader(InputStream) (returns a Reader)
+3). java.io.OutputStreamWriter(OutputStream) (returns a Writer)
+4). javax.xml.bind.annotation.adapters.XmlAdapter#marshal() and #unmarshal()
+
+Reference - http://www.tutorialspoint.com/design_pattern/adapter_pattern.htm

src/com/test/design/adapter/VlcPlayer.java

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+package com.test.design.adapter;
+
+public class VlcPlayer implements AdvancedMediaPlayer {
+	@Override
+	public void playVlc(String fileName) {
+		System.out.println("Playing vlc file. Name: " + fileName);
+	}
+
+	@Override
+	public void playMp4(String fileName) {
+		// do nothing
+	}
+}

src/com/test/design/builder/Bottle.java

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+package com.test.design.builder;
+
+public class Bottle implements Packing {
+
+	@Override
+	public String pack() {
+		return "Bottle";
+	}
+}

src/com/test/design/builder/BuilderPatternDemo.java

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+package com.test.design.builder;
+
+public class BuilderPatternDemo {
+	
+	public static void main(String[] args) {
+
+		MealBuilder mealBuilder = new MealBuilder();
+
+		Meal vegMeal = mealBuilder.prepareVegMeal();
+		System.out.println("Veg Meal");
+		vegMeal.showItems();
+		System.out.println("Total Cost: " + vegMeal.getCost());
+
+		Meal nonVegMeal = mealBuilder.prepareNonVegMeal();
+		System.out.println("\n\nNon-Veg Meal");
+		nonVegMeal.showItems();
+		System.out.println("Total Cost: " + nonVegMeal.getCost());
+	}
+}