Overview
POIFS is a pure Java implementation of the OLE 2 Compound
Document format.
By definition, all APIs developed by the POI project are
based somehow on the POIFS API.
A common confusion is on just what POIFS buys you or what OLE
2 Compound Document format is exactly. POIFS does not buy you
DOC, or XLS, but is necessary to generate or read DOC or XLS
files. You see, all file formats based on the OLE 2 Compound
Document Format have a common structure. The OLE 2 Compound
Document Format is essentially a convoluted archive
format. Think of POIFS as a "zip" library. Once you can get
the data in a zip file you still need to interpret the
data. As a general rule, while all of our formats use
POIFS, most of them attempt to abstract you from it. There
are some circumstances where this is not possible, but as a
general rule this is true.
If you're an end user type just looking to generate XLS
files, then you'd be looking for HSSF not POIFS; however, if
you have legacy code that uses MFC property sets, POIFS is
for you! Regardless, you may or may not need to know how to
use POIFS but ultimately if you use technologies that come
from the POI project, you're using POIFS underneith. Perhaps
we should have a branding campaign "POIFS Inside!". ;-)
by Andrew C. Oliver, Nicola Ken Barozzi
