Just a reminder of some confusing things about Nepomuk in KDE4.

A few of googling tell that it supports fulltext-indexing of variant types of files,
including pdf file. Unfortunately I failed to witness it in my KDE4 env. So I dig more
and get some info.

First newer KDE4 version uses virtuoso to do indexing work instead of old strigi, and
for pdf-indexing to work, you may need to install pdftotext. According to this post,
pdf should be supported. To check if a file has been indexed, go to info panel in Dolphin and
see if there is a ‘has hash’ property. and here is an explaination of some parts related to
Nepomuk infrastructure.

For trouble-shooting, there are some ways to try(see Nepomuk, re-indexing),
here are some quick excerpts.

index a file manually from console:
nepomukindexer /path/to/file

call dbus service to re-indexing a folder(only work for KDE 4.8):
qdbus org.kde.nepomuk.services.nepomukfileindexer /nepomukfileindexer org.kde.nepomuk.FileIndexer.indexFolder afolder 0 1