Programmatically doing 'Find Usages"

Hi Folks,

Pardon my newbie questions:

Background: i am writing a new search and recommend plugin for Java 
development (please correct if this is not the right forum)

1. Specifically, i am requesting suggestions for sample/open source code 
for "Find Usages". I wish to provide some additional user action based 
on the search results.

2. Once the user clicks on a particular field (i have that working using 
the sample CopyFQNAction plugin), i would like to display a new button.

Use case:

User selects any java.util.logging.Logger.log() statements in a Java 
file and the code should find all instances of similar log() statements 
in all the open projects (same as what is being done by 'Find Usages'. 
However, rather than display these in the Usage output window, i want to 
analyze the statement and provide logging recommendations to the user.

Thanks,
Sunil