Setting an Enum value based on incoming String

Question

I have a number of setter methods which take an enum. These are based on incoming objects attribute. Rather than write a bunch of these is there a way around having to hard code say 10 different case statements. Would there be a way to create a reusable method?

//Side class declared as
public final enum Side

//How I initialise side
static Side side = Side.SELL;//default

//method to set object
Obj.setSide(sideEnum(zasAlloc.getM_buySellCode()));

//How I am implementing it
    public static Side sideEnum(String buysell)
    {

        if(buysell.equalsIgnoreCase("S"))
        {
            side = Side.SELL; //default 
        }
        else if(buysell.equalsIgnoreCase("B"))
        {
            side = Side.BUY; 
        }

        return side;

    }

Answer 1

You can implement that functionality in your Enum.

public enum Side {

    BUY("B"), SELL("S"), ...

    private String letter;
    private Side(String letter) {
        this.letter = letter;
    }

    public static Side fromLetter(String letter) {
        for (side s : values() ){
            if (s.letter.equals(letter)) return s;
        }
        return null;
    }

}

You could also do this as a helper static method if you can't edit Side.

public static Side fromString(String from) {
    for (Side s: Side.values()) {
        if (s.toString().startsWith(from)) {
            return s;
        }
    }

    throw new IllegalArgumentException( from );
}

The above method assumes your strings correspond to the names of you enums.

Answer 2

Enums have valueOf() method that can be used to convert from String. Is it what you are looking for?

Answer 3

I ended up using a simple object map:

private static HashMap<String, Side> sideMap = new HashMap<String, Side>(7);
static{
    sideMap.put("B", Side.BUY);
    sideMap.put("S", Side.SELL);
}

and simply using

Obj.setSide(sideMap.get(zasAlloc.getM_buySellCode()));