Software to search through files (mostly PDF)

Question

I would like to know if there are some active open source projects to develop alternatives to Google Desktop or Regain for Windows 7.

The situation is the following:

• I have a folder full of PDF documents (organised in many subfolders). There is a least one document updated or created every day,
• I often need to search some words and sentences in these documents,
• Windows search and Agent Ransack are too slow and their interfaces do not suit my needs,
• The interface of Regain suits my needs almost perfectly: I type my search criteria and I get a list of result with a short overview, but I can't restrict the search perimeter to a specific directory,
• The last update to regain was on 2014-07-30 - this makes me wonder if it is outdated or uses obsolete components (and I wouldn't want to compromise the security of my computer),
• I searched on many websites before posting here (This topic led me to Regain).

Here is an example of search results with Regain:

Answer 1

I used to use Recoll and it was very neat: http://www.lesbonscomptes.com/recoll/ It uses poppler, the well-known PDF library.

Modern OS often have such search features by default, for instance Fedora provides Nepomuk. They can be very resource-intensive, though.

Answer 2

From Brian Z.'s answer: DocFetcher is a cross-platform solution under Eclipse Public License and seems very powerful judging from the documentation.

Answer 3

Anyway you mentioned that you have all the documents arranged in folders, in that case, try Adobe Reader's advance search feature.

Once you have opened the Adobe reader, Shift+Ctrl+F should bring up the interface [ or you can navigate by Edit(menu) -> Advance Search ] I noticed that for Regain you are running a server ( it must be a light weight one, but still its an extra process ) Screenshot is from Adobe Reader XI version.