facade added

Author: maciej-nowak

facade/README.md

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+# Facade
+This is repository of http://androidcode.pl blog. It shows uses of Facade in Android. It is a part of Design Patterns - Facade post in the blog.

facade/example/Main.java

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+public class Main {
+
+    private MediaPlayer mediaPlayer;
+
+    public static void main() {
+        mediaPlayer = new MediaPlayer(HardwarePlayer.Source.INTERNAL, true);
+    }
+
+    private void volumeDownClick() {
+        mediaPlayer.decreaseVolume();
+    }
+
+    private void volumeUpClick() {
+        mediaPlayer.increaseVolume();
+    }
+
+    private void nextSongClick() {
+        mediaPlayer.nextSong();
+    }
+
+    private void previousSongClick() {
+        mediaPlayer.previousSong();
+    }
+
+    private void stopClick() {
+        mediaPlayer.stop();
+    }
+
+    private void playClick() {
+        if(mediaPlayer.isPlaying()) {
+            mediaPlayer.pause();
+            //change image for play
+        }
+        else {
+            mediaPlayer.play();
+            //change image for pause
+        }
+    }
+}

facade/example/MediaPlayer.java

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+public class MediaPlayer {
+
+    private FileManager fileManager;
+    private HardwarePlayer hardwarePlayer;
+    private SongFile songFile;
+    private List<SongFile> songs;
+    private int currentSong;
+    private int currentVolume;
+    private boolean isPlaying;
+
+    public MediaPlayer(Source hardwareSource, boolean isSdCard) {
+        fileManager = new FileManager(isSdCard);
+        hardwarePlayer = new HardwarePlayer(hardwareSource);
+        songs = new ArrayList<>();
+        currentSong = 0;
+        currentVolume = 5;
+        isPlaying = false;
+        createPlaylist();
+    }
+
+    public void play() {
+        loadSong();
+        hardwarePlayer.play();
+        isPlaying = true;
+    }
+
+    public void pause() {
+        hardwarePlayer.pause();
+        isPlaying = false;
+    }
+
+    public void stop() {
+        hardwarePlayer.stop();
+        currentSong = 0;
+        isPlaying = false;
+    }
+
+    public void increaseVolume() {
+        if(currentVolume < 10)
+            currentVolume++;
+        changeVolume();
+    }
+
+    public void decreaseVolume() {
+        if(currentVolume > 0)
+            currentVolume--;
+        changeVolume();
+    }
+
+    public void nextSong() {
+        if(currentSong == songs.size() + 1)
+            currentSong = 0;
+        else
+            currentSong++;
+        changeSong();
+    }
+
+    public void previousSong() {
+        if(currentSong == 0)
+            currentSong = songs.size() - 1;
+        else
+            currentSong--;
+        changeSong();
+    }
+
+    public void loadSong() {
+        SongBytes songBytes = Converter.convertToBytes(songFile);
+        hardwarePlayer.load(songBytes);
+    }
+
+    public void createPlaylist() {
+        List<File> files = fileManager.readSongsList();
+        songs = Converter.convertToSongFiles(files);
+    }
+
+    public boolean isPlaying() {
+        return isPlaying;
+    }
+
+    private void changeVolume() {
+        hardwarePlayer.pause();
+        hardwarePlayer.setVolume(currentVolume);
+        hardwarePlayer.start();
+    }
+
+    private void changeSong() {
+        songFile = songs.get(currentSong);
+        hardwarePlayer.stop();
+        play();
+    }
+
+    //other methods
+}

facade/example/elements/Converter.java

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+public final class Converter {
+
+    public static SongBytes convertToBytes(SongFile songFile) {
+        //implementation;
+        return new SongBytes(); //mock
+    }
+
+    public static List<SongFile> convertToSongFiles(List<File> file) {
+        //implementation;
+        return Collections.emptyList(); //mock
+    }
+}

facade/example/elements/FileManager.java

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+public class FileManager {
+
+    public FileManager(boolean isSdCard) {
+        //implementation
+    }
+
+    public List<File> readSongsList() {
+        //implementation
+        return Collections.emptyList(); //mock
+    }
+}

facade/example/elements/HardwarePlayer.java

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+public class HardwarePlayer {
+
+    //variables
+
+    public HardwarePlayer(Source source) {
+        //implementation;
+    }
+
+    public void load(SongBytes songBytes) {
+        //implementation
+    }
+
+    public void play() {
+        //implementation
+    }
+
+    public void start() {
+        //implementation
+    }
+
+    public void pause() {
+        //implementation
+    }
+
+    public void stop() {
+        //implementation;
+    }
+
+    public void setVolume(int volume) {
+        //implementation
+    }
+
+    public enum Source {
+        INTERNAL(0),
+        EXTERNAL(1);
+
+        int source;
+        Source(int source) {
+            this.source = source;
+        }
+    }
+
+    //other methods
+
+}

facade/example/elements/SongBytes.java

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+public class SongBytes {
+	
+	//implementation
+}

facade/example/elements/SongFile.java

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+public class SongFile {
+
+	//implementation
+}

facade/pattern/Action.java

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+public enum Action {
+
+    INCREASE(0),
+    DECREASE(1),
+    DOUBLE(2);
+
+    int action;
+    Action(int action) {
+        this.action = action;
+    }
+}

facade/pattern/Element1.java

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+public class Element1 {
+
+    public void refreshState() {
+
+    }
+
+    public State getState() {
+        return new State();
+    }
+
+    public void increase() {
+
+    }
+
+    public void decrease() {
+
+    }
+
+    public void makeDouble() {
+
+    }
+}

facade/pattern/Element2.java

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+public class Element2 {
+
+    public void restart() {
+
+    }
+
+    public void startAction(State state) {
+
+    }
+}

facade/pattern/Facade.java

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+public class Facade {
+
+    private Element1 element1;
+    private Element2 element2;
+
+    public Facade() {
+        element1 = new Element1();
+        element2 = new Element2();
+    }
+
+    public void operation1(Action action) {
+        if(action == Action.INCREASE)
+            element1.increase();
+        else if(action == Action.DECREASE)
+            element1.decrease();
+        else if(action == Action.DOUBLE)
+            element1.makeDouble();
+        else
+        element2.restart();
+    }
+
+    public void operation2() {
+        if(Utils.isAccessProvided()) {
+            element2.startAction(element1.getState());
+            element1.refreshState();
+        }
+        else
+            Utils.printError();
+    }
+}

facade/pattern/State.java

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+public class State {
+
+	//implementation
+}

facade/pattern/Utils.java

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+public final class Utils {
+
+    public static boolean isAccessProvided() {
+        return true;
+    }
+
+    public static void printError() {
+
+    }
+
+}