Facade pattern java

Let's create a package called some_complex_media_library. Inside of this package we add an interface we will call Codec. Now let's add a class we call VideoFile. The code for **VideoFile** will be:

public class VideoFile {
    private String name;
    private String codecType;

    public VideoFile(String name) {
        this.name = name;
        this.codecType = name.substring(name.indexOf(".") + 1);
    }

    public String getCodecType() {
        return codecType;
    }

    public String getName() {
        return name;
    }
}

Now let's create a couple of classes that will *implement* Codec, MPEG4CompressionCodec and OggCompressionCodec.

public class MPEG4CompressionCodec implements Codec {
    public String type = "mp4";

}

And for OggCompressionCodec we have:

public class OggCompressionCodec implements Codec {
    public String type = "ogg";
}

Let also add a **CodecFactory** class.

public class CodecFactory {
    public static Codec extract(VideoFile file) {
        String type = file.getCodecType();
        if (type.equals("mp4")) {
            System.out.println("CodecFactory: extracting mpeg audio...");
            return new MPEG4CompressionCodec();
        }
        else {
            System.out.println("CodecFactory: extracting ogg audio...");
            return new OggCompressionCodec();
        }
    }
}


I also want to add a BitrateReader class.

public class BitrateReader {
    public static VideoFile read(VideoFile file, Codec codec) {
        System.out.println("BitrateReader: reading file...");
        return file;
    }

    public static VideoFile convert(VideoFile buffer, Codec codec) {
        System.out.println("BitrateReader: writing file...");
        return buffer;
    }
}

Let me add another class I call **AudioMixer**.

import java.io.File;

public class AudioMixer {
    public File fix(VideoFile result){
        System.out.println("AudioMixer: fixing audio...");
        return new File("tmp");
    }
}

Lastly we'll add a class we call **VideoConversionFacade**

import java.io.File;

public class VideoConversionFacade {
    public File convertVideo(String fileName, String format) {
        System.out.println("VideoConversionFacade: conversion started.");
        VideoFile file = new VideoFile(fileName);
        Codec sourceCodec = CodecFactory.extract(file);
        Codec destinationCodec;
        if (format.equals("mp4")) {
            destinationCodec = new OggCompressionCodec();
        } else {
            destinationCodec = new MPEG4CompressionCodec();
        }
        VideoFile buffer = BitrateReader.read(file, sourceCodec);
        VideoFile intermediateResult = BitrateReader.convert(buffer, destinationCodec);
        File result = (new AudioMixer()).fix(intermediateResult);
        System.out.println("VideoConversionFacade: conversion completed.");
        return result;
    }
}

Now let's create a facade packabge. Inside this package we add a VideoConversionFacade class:

import java.io.File;

public class VideoConversionFacade {
    public File convertVideo(String fileName, String format) {
        System.out.println("VideoConversionFacade: conversion started.");
        VideoFile file = new VideoFile(fileName);
        Codec sourceCodec = CodecFactory.extract(file);
        Codec destinationCodec;
        if (format.equals("mp4")) {
            destinationCodec = new OggCompressionCodec();
        } else {
            destinationCodec = new MPEG4CompressionCodec();
        }
        VideoFile buffer = BitrateReader.read(file, sourceCodec);
        VideoFile intermediateResult = BitrateReader.convert(buffer, destinationCodec);
        File result = (new AudioMixer()).fix(intermediateResult);
        System.out.println("VideoConversionFacade: conversion completed.");
        return result;
    }
}

Now let's put this all together in a Demo class which will have a main method.

import java.io.File;

public class Demo {
    public static void main(String[] args) {
        VideoConversionFacade converter = new VideoConversionFacade();
        File mp4Video = converter.convertVideo("youtubevideo.ogg", "mp4");
        // ...
    }
}

Let's compile this an run it, we should get:

VideoConversionFacade: conversion started.
CodecFactory: extracting ogg audio...
BitrateReader: reading file...
BitrateReader: writing file...
AudioMixer: fixing audio...
VideoConversionFacade: conversion completed.

The Ray Code is AWESOME!!! [Wikipedia](https://en.wikipedia.org/wiki/Decorator_pattern) ---------------------------------------------------------------------------------------------------- Find Ray on: [facebook](https://www.facebook.com/TheRayCode/) [youtube](https://www.youtube.com/user/AndradeRay/) [The Ray Code](https://www.RayAndrade.com) [Ray Andrade](https://www.RayAndrade.org)