Capturing Data from another program... is it possible?

Hello,

I am trying to write a program that will act as a "supplement" to an existing program which I do not have the code for or own. Everytime this program is in use and they enter a certain part of this program (for instance, if it was excel, and i wanted to add the supplement to evertime they create a graph) I need to be able to popup my program so that the user can use it w/ minimum initialization on their part. Additionally, I need to be able to capture certain data from the other program, which is always in the same location.

Is this a possible task in Visual Basic? I am assuming that I need to somehow be able to listen to all window messages and then take appropriate action when the program I am monitoring is active... but this is a reaml I have never wandered into before. Additionally, is it possible to capture the text data from another program? The program that I need to capture the data from is a java based program run on a win machine. I can actually click on the program and get all of the data for this particular screen I am interested in as an XML file, so if there is a way to run a macro on another program to automatically right click and get the xml file, that could also be a possiblility.

I would really appreciate it if someone could give me some pointers!
Thanks,

Fuz

This is a very tricky task without any documentation. Usually you would have access to the program's API, or an SDK, which would allow you to see inputs and outputs of the program. Without these, you'll never really know what's going.