TODAYS LITTLE CHALLENGE FOR JAVA DEVELOPERS!!!

Question

This challenge is related to EventListener.
I initialized a String i.e
String data = "myname";
What i wnat to do;
whenever the string data changes some event generate's so that in Listener
method i received the the data .
What kind of Listener should be used i not no.
Be sure not to initialize like this "static String data = "myname";
Example:
String data = "myname";
data.add...Listener(this);
for(int i = 0; i< 10; i++)
data = "myname"+i;
public event...Listaner( Event ...e)//Event listener
string s = e.getdata();// OR some other function
Thank's

Answer 1

First, I think this is a cool idea, and there is a new language specifically designed to achieve this kind of event programming.
Second, I don't think this can be done with the Java language, at least not with the current Java architecture. Among the few problems implementing this, the greatest obstacle is here:
String data = "myname";
data = "myname"+i;Now, to event trigger this data = "myname" + i; , or to the JVM data = new String("myname" + i); , is problematic. The String variable data did not change value, it changed its reference. You can not intercept the = operator in Java. You can not change the String constructor behavior legally. (Well, even you do, it applies to all Strings and not just the data variable).
So, the only work around solution to achieve a similar effect is to wrap the String class to a MutableString class. (Note: wrap, not extend) And expose get/set method for this wrapper string class, then you can do whatever listener in the get/set method of your class. However, you still can not add listener for object reference change.
The above is only my take though. Do you have the answer to the challenge? I would love to hear others or the answer.
--lichu