For string constants its usual to use a class with final String values. But whats the best practice for storing string array. I want to store different categories in a constant array and everytime a category has been selected, I want to know which category it belongs to and process based on that.

Addition : To make it more clear, I have a categories A,B,C,D,E which is a constant array. Whenever a user clicks one of the items(button will have those texts) I should know which item was clicked and do processing on that.

I can define an enum(say cat) and everytime do

if clickedItem == cat.A
else if clickedItem = cat.B
else if 

or even register listeners for each item seperately.

But I wanted to know the best practice for doing handling these kind of problems.

3 Answers 3


I much prefer using Enums to store system wide string constants, makes it easy to create additional functionality and I think it is generally accepted best practice.

public enum Cat {
     A() {
          @Override public void execute() { 
               System.out.println("A clicked"); 
     B() {
          @Override public void execute() { 
               System.out.println("B Clicked"); 
     //template method
     public abstract void execute();

then you can call it like so :

String clickedItem = "A";    
Cat.valueOf(clickedItem).execute(); //will print A is clicked

or you could also the Command pattern without enums....

public interface Cat {
     void do();

public class CatA() implements Cat {
     void do() {//put your code here}
public class CatB() implements Cat {
     void do() {//put your other code here}

then build a Map object and populate it with Cat instances:

catMap.put("A", new CatA());
catMap.put("B", new CatB());

then you can replace your if/else if chain with:


Your description is quite vague, so maybe I got this wrong, but it sounds as you could use a Map<String,String> storing your category relationships. E.g. if you have

class Foo {
   final static String[] cat1 = {"val1_1","val1_2","val1_3"};
   final static String[] cat2 = {"val2_1","val2_2"};

I would write:

class Foo {
  final static Map<String, String> map = new HashMap<String,String>();

Then getting the category is as easy as calling Foo.map.get("val1_1");. Of course you should be a little bit more clever than me filling when filling the map (e.g. from a file or so). If you are concerned with changes of the map, wrap it using Collections.unmodifiableMap.

  • 2
    To guarantee that the values aren't modified, you could wrap the map with Collections.unmodifiableMap(). Commented Nov 15, 2011 at 16:55

As for your question - it is unclear what exactly you want to achieve, but I could just give you some general advices about using enum:

  • An enum constant is an object and enum class name should start with uppercase (Cat)
  • An enum is a fixed, finite set of enum constants. Don't use where you need variability.
  • Enums can reference other objects. Final references of immutable objects are recommended. This can be very useful e.g. to store your string constants.
  • Enum constant can be used as a map key, but also as a switch-case constant. It is definitely nicer than using a long if-else tree.

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