ReplaceTextWithMapping how to regex

[Mika Borner]

Hi all

I'm not sure I understand how the ReplaceTextWithMapping processor 
works. Let's say my flowfile content looks like:

    xyz key=value1 foo bar value1

My mapping file looks like:

    value1    replacementvalue1

    value2    replacementvalue2

I just want to replace the occurrence of "value1" only when it's 
perpended with "key=". Therefore I'm writing the Regex "key=(\S+)" and a 
"Matching Group" of 1.

This unfortunately doesn't work.

Can someone explain, what's wrong?

Thanks!

Mika>