Duplicate static field (Array vs String)

Question

I have a question about the following code:

public Class Settings{
 public static final String WelcomeMessage= "helloworld";
 public static final String ByeMessage= "yo";

public static String[] widgets = {WelcomeMessage,ByeMessage};

}

The compiler complains about duplicat variables. Can I delete the 2 separate variables and still acces WelcomeMessage by Settings.WelcomeMessage? I don't need to acces it by Settings.widget[0]? And is it possible to add another variable to the WelcomeMessage variable (by for instance using a static hashtable)?

Edit: I know this code doesn't look right but it's just an example because I wondered why the compiler thinks WelcomeMessage (as a separata variable) is the same as the variable in the Widgets array.

What is the atual warning/error message from the compiler? Note that these three contents are not related, they have different names and values! "WelcomeMessage" is not a reference to static field, it's just a String "WelcomeMessage". — Grzegorz Oledzki
– Grzegorz Oledzki, Commented Feb 10, 2011 at 10:30
In your code, Settings.WelcomeMessage is "helloworld", while Settings.widgets[0] is "WelcomeMessage". They are not the same. Maybe you didn't mean to put the double quotes in the widgets array? — MAK
– MAK, Commented Feb 10, 2011 at 10:32
The definition should write class (with lowercase 'c'). Other than that my compiler doesn't complain. — Mnementh
– Mnementh, Commented Feb 10, 2011 at 10:52

Mnementh · Accepted Answer · 2011-02-10 10:44:15Z

2

I would consider java-enums in your case:

public enum Settings {
    WelcomeMessage ("helloworld"),
    ByeMessage   ("yo");

    public final String value;

    Settings(String value) {
        this.value = value;
    }
}

You can access now the values via Settings.WelcomeMessage.value. Also you get a List of the enums with Settings.values().

answered Feb 10, 2011 at 10:44

Mnementh

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Comments

Jonathan Holloway · Accepted Answer · 2011-02-10 10:33:12Z

1

You've marked the fields as public static which means that yes you'll be able to access them via:

Settings.WelcomeMessage

or if you you use a static import in your class, just:

WelcomeMessage

You haven't actually used these constants in the widgets array, you've just created two new strings in there "WelcomeMessage" and "ByeMessage"

public static String[] widgets = {"WelcomeMessage","ByeMessage"};

No, if you delete the WelcomeMessage and ByeMessage constants you can't access them in that way, you'd have to go through the widgets array and access them as:

Settings.widgets[0]

answered Feb 10, 2011 at 10:33

Jonathan Holloway

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trojanfoe · Accepted Answer · 2011-02-10 10:57:42Z

0

I think you meant to use this instead:

public Class Settings
{
    public static final String WelcomeMessage= "helloworld";
    public static final String ByeMessage= "yo";

    public static String[] widgets = {WelcomeMessage,ByeMessage};
}

But this is better:

public Class Settings
{
    public static String[] widgets = {"WelcomeMessage","ByeMessage"};
}

And yes you can access WelcomeMessage via Settings.widgets[0].

Edit: Oops - yep - of course you cannot access them by name, only index into the array.

Edit 2: If you make the field protected or private and provide 'getter' methods, then it doesn't matter to any user classes how they are implemented:

public Class Settings
{
    private static final String welcomeMessage= "helloworld";
    private static final String byeMessage= "yo";

    public static String getWelcomeMessage()
    {
        return welcomeMessage;
    }

    public static String getByeMessage()
    {
        return byeMessage;
    }
}

edited Feb 10, 2011 at 10:57

answered Feb 10, 2011 at 10:32

trojanfoe

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2 Comments

Mnementh Over a year ago

You cannot access the value via Settings.widgets.WelcomeMessage. It would be Settings.widgets[0]. EDIT: Was corrected.

trojanfoe Over a year ago

@Mnementh: Corrected. Brainfreeze!

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