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;

    }

Dave Jarvis · Accepted Answer · 2013-03-11 22:17:20Z

26

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.

edited Mar 11, 2013 at 22:17

Dave Jarvis

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answered May 31, 2011 at 14:24

jjnguy

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2 Comments

Peter Over a year ago

Minor comment, if you have a lot of enums and the fromLetter() method is called often, it may make sense to create a static HashMap to make lookup/retrieval faster. But your solution makes perfect sense!

jjnguy Over a year ago

@Peter, correct. This is just the quick and dirty way. But the hashmap is definitely worth noting.

Alex Gitelman · Accepted Answer · 2011-05-26 15:00:24Z

6

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

answered May 26, 2011 at 15:00

Alex Gitelman

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4 Comments

Joseph Over a year ago

ENUM1("one","1","I") Create your own method similar to value of such as getEnum(String s). This would allow you to return ENUM1 for any of the attribute values. valueOf works fine for many cases though.

Will Over a year ago

Comment it's more the kind that if the string that comes in is "d" it maps to static enum side.DOG

mre Over a year ago

@Will, this is why you need to provide some code, otherwise we're all left shooting in the dark.

Will Over a year ago

I realise this but Unfortunately. I working with two Objects I do not have access to the source.

Will · Accepted Answer · 2011-07-05 16:00:59Z

2

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()));

answered Jul 5, 2011 at 16:00

Will

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Comments

bigGuy · Accepted Answer · 2011-05-31 14:26:17Z

0

I think you need smth like:

Obj.setSide(Side.valueOf(zasAlloc.getM_buySellCode()));

answered May 31, 2011 at 14:26

bigGuy

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