using switch in strings

Question

Trying to use switch in strings by first coverting string into char and then apply switch but still didnt done it....here is my code..

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import javax.swing.JOptionPane;

class HappyBirthday {

    public static void main(String[] args) throws IOException {
        String Month;
        char[] Months = Month.toCharArray();
        BufferedReader dataIn = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Please enter your month.");

        Month = JOptionPane.showInputDialog("enter month");
        String month1 = { "January", "feb"};
        char[] month2 = month1.toCharArray();

        // String s=month1.equals(Month);
        // System.out.print(month2Array[0]);
        switch (month2) {

        case 0:
            System.out.println("kool");
            break;

        case 1:
            System.out.println("not kool");
            break;
        default:
        }
    }
}
/**
 * if (month1[1].equals(Month)) System.out.println("kool"); else
 * if(month1[0].equals(Month)) System.out.println("kooooooooooooool"); else
 * System.out.println("Big kooooool");
 **/

Answer 1

Have a look at this excellent article on the subject.

Answer 2

You can't switch on a char[] type. Switch on char[0] and use case 'J': and so on (although - because some months start with the same letter, the algorithm would be sub-optimal)

Answer 3

Note that switching on strings will be supported in Java 7.

Answer 4

Currently, you can not switch on a String. The language specification is clear on what you can switch on:

JLS 14.11 The switch statement

SwitchStatement:
      switch ( Expression ) SwitchBlock

The type of the Expression must be char, byte, short, int, Character, Byte, Short, Integer, or an enum type, or a compile-time error occurs.

Depending on what you want to do, you can switch on each char of a String:

    String s = "Coffee, tea, or me?";
    int vowelCount = 0;
    int punctuationCount = 0;
    int otherCount = 0;
    for (char letter : s.toUpperCase().toCharArray()) {
        switch (letter) {
            case 'A': 
            case 'E':
            case 'I':
            case 'O':
            case 'U':
                vowelCount++;
                break;
            case ',':
            case '.':
            case '?':
                punctuationCount++;
                break;
            default:
                otherCount++;
        }
    }
    System.out.printf("%d vowels, %d punctuations, %d others",
        vowelCount, punctuationCount, otherCount
    ); // prints "7 vowels, 3 punctuations, 9 others"