[ACCEPTED]-Scala: public static final in a class-scala

Accepted answer

Score: 11

object Foo{
  val MY_STRINGS=Array("A","B","C")
}
class Foo{
  import Foo.MY_STRINGS
}

The val definition in the companion object 8 creates your public static final variable, and the import declaration 7 gives it a nice easy alias in the code you're 6 using to write the class.

Note that the public static final variable 5 in Scala still will compile to look like 4 a static method call if you call this code 3 from Java.

Edit: I'm slightly wrong because of 2 a bug in Scala 2.7, which I demonstrate 1 in detail in another answer.

Score: 7

The following Scala code:

class Foo{
  import Bar.MY_STRINGS
}
object Bar{
  val MY_STRINGS=Array("A","B","C")
}

Generates the following 9 Java classes:

public final class Bar extends java.lang.Object{
    public static final java.lang.String[] MY_STRINGS();
    public static final int $tag()       throws java.rmi.RemoteException;
}
public final class Bar$ extends java.lang.Object implements scala.ScalaObject{
    public static final Bar$ MODULE$;
    public static {};
    public Bar$();
    public java.lang.String[] MY_STRINGS();
    public int $tag()       throws java.rmi.RemoteException;
}
public class Foo extends java.lang.Object implements scala.ScalaObject{
    public Foo();
    public int $tag()       throws java.rmi.RemoteException;
}

The following Scala code:

class Foo{
  import Foo.MY_STRINGS
}
object Foo{
  val MY_STRINGS=Array("A","B","C")
}

Generates 8 the following Java classes:

public class Foo extends java.lang.Object implements scala.ScalaObject{
    public Foo();
    public int $tag()       throws java.rmi.RemoteException;
}
public final class Foo$ extends java.lang.Object implements scala.ScalaObject{
    public static final Foo$ MODULE$;
    public static {};
    public Foo$();
    public java.lang.String[] MY_STRINGS();
    public int $tag()       throws java.rmi.RemoteException;
}

The fact that 7 static members aren't defined on the class 6 when the object has the same name as the 5 class is Scala Bug #1735 and it's fixed in Scala 2.8 snapshots.

So 4 it looks like TwiP isn't going to work at 3 all unless you either upgrade Scala, or 2 find a way to get TwiP to work with non-Static 1 parameter generation methods.

Score: 2

You just have to define the variable as 4 "val" in a companion object.

object Foo{
  val MyStrings = Array("A","B","C")
}

NOTE: final 3 static variables in scala doesn't follow 2 the same convention as in Java. Take a look 1 at: http://docs.scala-lang.org/style/naming-conventions.html

Score: 1

If you use a var then you can create your 6 own getter and setter, and if the value 5 is already set, don't change it.

That may 4 not be the best approach, but it would be 3 helpful if you could explain why you want 2 to use public static final on a variable, as a better solution 1 might be more obvious then.

Source: stackoverflow.com

[ACCEPTED]-Scala: public static final in a class-scala

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