Question

I want to read Object from string expression. eg:

I have following string:

(3:2,1) 

or

(3:null,1)

now I want to read Object1=3; Object2=2; Object3=1 or

Object1=3; Object2=null; Object3=1.

How can I read it in Java.

Answer 1

I am usually not a big fan of regular expressions, but this is a perfect example of where the proper application of a regular expression is simpler and most importantly easier to maintain than other String manipulation based solutions.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Parser
{
    public static void main(final String[] args)
    {
        final String s1 = "(3:2,1)";
        final String s2 = "(3:null,1)";
        final Pattern p = Pattern.compile("\\((\\d+):(\\d+|null),(\\d+)\\)");
        final Matcher m1 = p.matcher(s1);
        m1.matches();
        System.out.format("Object1=%s; Object2=%s; Object3=%s", m1.group(1), m1.group(2), m1.group(3));
        System.out.println();
        final Matcher m2 = p.matcher(s2);
        m2.matches();
        System.out.format("Object1=%s; Object2=%s; Object3=%s", m2.group(1), m2.group(2), m2.group(3));
    }
}

As per your requirements the expected output looks like

Object1=3; Object2=2; Object3=1
Object1=3; Object2=null; Object3=1