Conveniently map between enum and int / String

Question

When working with variables/parameters that can only take a finite number of values, I try to always use Java\'s enum, as in

public enum BonusT         


        

Answer 1

A very clean usage example of reverse Enum

Step 1 Define an interface EnumConverter

public interface EnumConverter  & EnumConverter> {
    public String convert();
    E convert(String pKey);
}

Step 2

Create a class name ReverseEnumMap

import java.util.HashMap;
import java.util.Map;

public class ReverseEnumMap & EnumConverter> {
    private Map map = new HashMap();

    public ReverseEnumMap(Class valueType) {
        for (V v : valueType.getEnumConstants()) {
            map.put(v.convert(), v);
        }
    }

    public V get(String pKey) {
        return map.get(pKey);
    }
}

Step 3

Go to you Enum class and implement it with EnumConverter and of course override interface methods. You also need to initialize a static ReverseEnumMap.

public enum ContentType implements EnumConverter {
    VIDEO("Video"), GAME("Game"), TEST("Test"), IMAGE("Image");

    private static ReverseEnumMap map = new ReverseEnumMap(ContentType.class);

    private final String mName;

    ContentType(String pName) {
        this.mName = pName;
    }

    String value() {
        return this.mName;
    }

    @Override
    public String convert() {
        return this.mName;
    }

    @Override
    public ContentType convert(String pKey) {
        return map.get(pKey);
    }
}

Step 4

Now create a Communication class file and call it's new method to convert an Enum to String and String to Enum. I have just put main method for explanation purpose.

public class Communication & EnumConverter> {
    private final E enumSample;

    public Communication(E enumSample) {
        this.enumSample = enumSample;
    }

    public String resolveEnumToStringValue(E e) {
        return e.convert();
    }

    public E resolveStringEnumConstant(String pName) {
        return enumSample.convert(pName);
    }

//Should not put main method here... just for explanation purpose. 
    public static void main(String... are) {
        Communication comm = new Communication(ContentType.GAME);
        comm.resolveEnumToStringValue(ContentType.GAME); //return Game
        comm.resolveStringEnumConstant("Game"); //return GAME (Enum)
    }
}

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