I'm wondering if it is better to use a final static variable or method to provide a constant array in Java.
Say we have:
public class myColor {
public final static String[] COLOR_NAMES = new String[] {"red", "green"};
public final static String[] colorNames() {return new String[] {"red", "green"};}
}
To me, the second one has the disadvantage that each time it's called a new String array is created. But the first one has the disadvantage, that anyone could do COLOR_NAMES[0] = "blue"
.
To clarify: I specifically want to provide a list of color names for a subsequent match with regular expressions.
Is there any established way how this is typically solved?
You can use enum
public enum Color{
RED("red"), GREEN("green");
final String color;
Color(String color) {
this.color=color;
}
public String getColor() {
return color;
}
}
This question is fall for using Enum
. Personally I wont be using any method for that. But weather static array is good solution for that? It is better to solve it using java enums .
To initialise an array at construction time you can specify a list values in curly braces:
private static final String[] STRING_ARRAY = {"red", "green", "blue"};
In my example I have assumed that you won't want to change the instance of array and so have declared it final. You still would be able to update individual entries like so:
array[0] = "1";
But you won't be able to replace the array with a different one completely. If the values are going to change a lot - especially if the number of values are going to change - then it may be worth considering using List instead.
If you can go with a list, one option would be:
public final static List<String> COLOR_NAMES = Collections.unmodifiableList(
Arrays.asList("red", "green"));
You can always get an array if needed:
String[] array = COLOR_NAMES.toArray(new String[0]);
Otherwise your second option is fine although I would write it:
private final String[] COLOR_NAMES = {"red", "green"};
public static String[] getColorNames() { return COLOR_NAMES.clone(); }
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