how to use Switch with a string

Question

I have the code below that I wrote to get rid of a huge mess of if then else statements. The only problem is, I just found out that the Switch statement cannot be used with a string.

Is there a trick to get around this?

Thanks

switch(xpp.getName()) {
            case("creature") : attribID = Integer.parseInt(xpp.getAttributeValue(0));
            case("name") : elName = xpp.getName(); break;
            case("race") : elName = xpp.getName(); break;
            case("gender") : elName = xpp.getName(); break;
            case("alignment") : elName = xpp.getName(); break;
            case("age") : elName = xpp.getName(); break;
            case("condition") : elName = xpp.getName(); break;
            case("skinColor") : elName = xpp.getName(); break;
            case("hairColor") : elName = xpp.getName(); break;
            case("size") : elName = xpp.getName(); break;
            case("height") : elName = xpp.getName(); break;
            case("weight") : elName = xpp.getName(); break;
            case("hitPoints") : elName = xpp.getName(); break;
            case("armorClass") : elName = xpp.getName(); break;
            case("actionPoints") : elName = xpp.getName(); break;
            case("magicPoints") : elName = xpp.getName(); break;
            case("strength") : elName = xpp.getName(); break;
            case("dexterity") : elName = xpp.getName(); break;
            case("intelligence") : elName = xpp.getName(); break;
            case("weapon") : elName = xpp.getName(); break;
            case("armor") : elName = xpp.getName(); break;
            case("magicItem") : elName = xpp.getName(); break;
            case("attackSpell") : elName = xpp.getName(); break;
            case("defenseSpell") : elName = xpp.getName(); break;
            case("item1") : elName = xpp.getName(); break;
            case("item2") : elName = xpp.getName(); break;
        }

Yeah, use a JDK that supports switching on strings (i.e. Java 7). — mre, Feb 24 '12 at 18:20
duplicate - http://stackoverflow.com/questions/338206/switch-statement-with-strings-in-java — Micah Armantrout, Feb 24 '12 at 18:21
This is just a dummy code right? this case statement looks pretty ridiculous if it isn't. The above looks like it should be a single if-else statement. — sam yi, Feb 24 '12 at 18:26

smessing · Answer 1 · 2012-02-24T18:57:49.917

As an alternative, if you can't just switch to Java 7, the simplest method would be to replace the switch statement with a bunch of if else's. Alternatively, you could try switching on the hashCode of the string, but I'd only recommend that if you're sure you have no collisions (hashCode() is not guaranteed to prevent collisions!). The clearest and most simple solution would be using if else's. It maintains readability and allows you to still support older versions of Java.

EDIT: Only one case does something different! Why not simply do:

if (xpp.getName().equals("creature") {
    attribID = Integer.parseInt(xpp.getAttributeValue(0));
} else {
    elname = xpp.getName();
}

Andreas Dolk · Answer 2 · 2012-02-24T18:34:17.923

Java 7 supports switch on Strings, but it won't work with android.

I'd recommend using enums. Create one enum class and name the enums like your expected strings. Then you can determine the enum for a given String and switch on it.

Here's an example:

Number.java

public enum Number { one, two, three }

Switcher.java

public class Switcher {
    public static void main(String[] args) {
        String input = "one";
        switch (Number.valueOf(input)) {   // <- that's the magic!
        case one:System.out.println("1");break;
        case two:System.out.println("2");break;
        case three:System.out.println("3");break;
        }
    }
}

score 2 · Answer 3 · answered Feb 24 '12 at 18:28

Re-think your design. Make it more object-oriented. Use anonymous classes, maybe, or some kind of dispatch table. Or just simplify it. It looks like there are only 2 choices anyway ("creature" does one thing, eveything else does the other). Code that is hard to maintain is a prime candidate for refactoring.

score 2 · Accepted Answer · answered Feb 24 '12 at 18:39

You are doing the same thing for all cases exept then xpp.getName() is "creature". This means that all your code can easily be transformed into a singel if statement

if ( xpp.getName().equal("creature"))
     attribID = Integer.parseInt(xpp.getAttributeValue(0));
else
     elName = xpp.getName();

It also looks like you should start to program more object orientated and create some classes instead of using a name to determine what the object is

score 1 · Answer 5 · answered Feb 24 '12 at 18:23

Switches for strings is only available for Java 7. So you need to use a Java 7 SDK for compiling your code.

However, if you are using Eclipse as an IDE for developing an Android application you won't be able to set the code compliance level to Java 7 for your android project. You will then either have to wait for the android folks to support java 7 or alternatively use IntelliJ or compile your code from command line with the java 7 sdk and then use the dex compiler...

how to use Switch with a string

5 Answers5