Java Best way to extract parts from a string

Question

I have the following string;

[Username [rank] -> me] message

The characters of the rank, username, and message will vary each time. What

Answer 1

String input = "[whatever [Is] -> me] Input";
String user, rank, message;

user = input.substring(1, input.indexOf('[', 1));
rank = input.substring(input.indexOf('[', 1), input.indexOf(']'));
message = input.substring(input.lastIndexOf(']'));

this should work but if you really want it done right you should make a separate object that holds all this and can output it as a string. depends where this is coming from and where its going. -axon

Answer 2

Use Java's support for regular expressions (java.util.regex) and let a regex match the 3 parts.

For example this one: ^\[([\w]+) \[([\w]+)\] -> \w+\] (.*)$

Java code snippet, slightly adapted from Ian F. Darwin's "Java Cookbook" (O'Reilly):

import java.util.regex.*;

class Test
{
    public static void main(String[] args)
    {
        String pat = "^\\[([\\w]+) \\[([\\w]+)\\] -> \\w+\\] (.*)$";
        Pattern rx = Pattern.compile(pat);
        String text = "[Username [rank] -> me] message";
        Matcher m = rx.matcher(text);
        if(m.find())
        {
            System.out.println("Match found:");
            for(int i=0; i<=m.groupCount(); i++)
            {
                System.out.println("  Group " + i + ": " + m.group(i));
            }
        }
    }
}

Output:

Match found:
  Group 0: [Username [rank] -> me] message
  Group 1: Username
  Group 2: rank
  Group 3: message