Enum in java 1.4

Hi All,
i have a method that returns string value and i want to use this string in the switch case. I tried using enum but it is not available in JAVA 1.4. can anbody suggest something.

Please ask such non SCJP specific questions in our Java In General (intermediate) forum. Moving...

Originally posted by deshdeep divakar:
Hi All,
i have a method that returns string value and i want to use this string in the switch case. I tried using enum but it is not available in JAVA 1.4. can anbody suggest something.

You can only use integer values in switch statements. So if you must use a switch statement, you'll need to write some code to map your String to an integer value, and test that. Alternatively just use an if statement.

i Cant use if else as the ladder will be too long. n how do i map it to integer. Cant i use Enumeration...???

i Cant use if else as the ladder will be too long

Will the switch statement not be of a simmilar length?

n how do i map it to integer.

Define a class which contains public static final integer values for each of the supported conditions and write method that takes a String and returns one of these integer values. You don;t need this though if you just use an if statement directly on the String value.

Cant i use Enumeration...???

No. An Enumeration is a legacy class for iterating through the values of a Vector or Hashtable. And enums are not available till JDK 1.5.

There is not switch statement in java for Strings. But i think you can solve it using 'Chain of responsability' pattern if you have a lot of case statements. If you have just 3 or 4 case statements use if-then-else with the String.equals evaluation.

I'm not sure how a Chain of Responsibility would fit here. But you could use a Command pattern, and put the commands in a map. Here's a quick example:

import java.util.Map;
import java.util.HashMap;
 
public class Test {
    private interface Command {
        void execute();
    }
 
    private static final Map<String,Command> commandMap = loadCommandMap();
 
    private static Map<String, Command> loadCommandMap() {
        Map<String,Command> map = new HashMap<String, Command>();
        map.put("hi", new Command() {
            public void execute() {
                System.out.println("Hello");
            }
        });
        map.put("bye", new Command() {
            public void execute() {
                System.out.println("Goodbye");
            }
        });
        return map;
    }
 
    private static void perform(String s) {
        Command c = commandMap.get(s);
        if (c == null)
            throw new IllegalArgumentException("Unrecognized command string: [" + s + "]");
        c.execute();
    }
 
    public static void main(String args[]) throws Exception {
        perform("hi");
        perform("bye");
    }
}

Depending on what sorts of things you need to do here, you may want to define execute() with some arguments, or give it a non-void return type.