Using Java BDB in JRDF

Currently, one of the implementations used to store triples in JRDF is BDB. It has its own set of idioms to be aware of when being used.

Creating a new MapFactory

Unlike the in memory map factory the BDB MapFactory is tied to a BDB Environment which must be carefully managed.

If you wish to use a the MapFactory outside of the JRDF Graph Factory the way to construct a map factory is as follows:

// Create a new directory that implements the DirectoryHandler interface.
// Do no use the TempDirHandler (this is for the JRDF's use only)
DirHandler dirHandler = new DirHandler();
BdbEnvironmentHandler envHanlder = new BdbEnvironmentHandlerImpl(dirHandler);
// Ensure that the database name, the second entry, is unique
MapFactory mapFactory = new BdbMapFactory(handler, "seqDB");

If you wish to cleanup (delete directories and remove memory used) ensure to call close on the mapFactory:

mapFactory.close();
dirHandler.removeDir();