A simple application implementation of the Java policy pattern

After using the image processing software to process the image, you need to choose a format to save. However, different formats implement different algorithms at the bottom, which is just right for the policy pattern. Write a program that demonstrates how to develop using a combination of policy patterns and simple factory patterns.

The idea is as follows:

1. Use interface to define an interface, in which the save() method is defined;
2. Define different classes according to the image format, and implement an interface in each of these classes using the keyword implements;
3. Create a class to implement the selection, and define the method to implement the selection in this class. The method returns the value to save the class for the corresponding picture;
Implement the interface in the main method.
The code is as follows:

public interface ImageSaver { 
    void save();//Define the save() method
} 

public class GIFSaver implements ImageSaver { 
    @Override
    public void save() {//Implement the save() method
        System.out.println(" Save the picture as GIF format "); 
    } 
} 

public class JPEGSaver implements ImageSaver { 

    @Override
    public void save() { 
        System.out.println(" Save the picture as JPG format "); 
    } 
} 

public class PNGSaver implements ImageSaver { 

    @Override
    public void save() { 
        System.out.println(" Save the picture as PNG format "); 
    } 

} 

public class TypeChooser { 
    public static ImageSaver getSaver(String type) { 
        if (type.equalsIgnoreCase("GIF")) {//Use the if else statement to determine the type of image
            return new GIFSaver(); 
        } else if (type.equalsIgnoreCase("JPEG")) { 
            return new JPEGSaver(); 
        } else if (type.equalsIgnoreCase("PNG")) { 
            return new PNGSaver(); 
        } else { 
            return null; 
        } 
    } 
} 

public class User { 
    public static void main(String[] args) { 
        System.out.print(" The user selects GIF Format: "); 
        ImageSaver saver = TypeChooser.getSaver("GIF");//Gets an object that saves the image as a GIF
        saver.save(); 
        System.out.print(" The user selects JPEG Format: ");//Gets an object that saves the image as a JPEG
        saver = TypeChooser.getSaver("JPEG"); 
        saver.save(); 
        System.out.print(" The user selects PNG Format: ");//Gets an object of type PNG to save the image
        saver = TypeChooser.getSaver("PNG"); 
        saver.save(); 
    } 
} 

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