[Geotools-gt2-users] spatial indexing support for shapefiles

[<Eam...@cs...>]

Im looking to implement a quadtree spatial index in java for use on a 
mobile device. The the shapefiles will be read-only (mostly) so in order 
to speed up the application I need to be able to store the index in 
memory instead of re-generating it each time the application is loaded. 
I've heard mention of .qix files and have come accross libraries that 
can generate them but haven't been able to find any description of the 
file format anywhere. Does anyone know about these files or does 
geotools have a index file that works similarly?

Thanks,
- Éamonn