Java based connectivity drivers

[Lionel Elie Mamane]

On Fri, Jan 13, 2017 at 01:44:42PM +0100, Bunth Tamás wrote:

> I'd like to have a better understanding of how the hsqldb and jdbc
> drivers work.

> Is there any wiki page for them like "FirebirdSQL" for firebird that
> I couldn't find?

Nah, I don't think so, not on the TDF/LibreOffice wiki. There are some
on the OpenOffice wiki, but not what (I think) you are looking for:

https://wiki.openoffice.org/wiki/Base/connectivity/HSQLdb#HSQLDB
https://wiki.openoffice.org/wiki/HSQLDB_Integration
https://wiki.openoffice.org/wiki/HSQLDB:Tips_and_Tricks
https://wiki.openoffice.org/wiki/HSQLDB_Localization

> The code in connectivity/source/drivers/jdbc contains a bunch of java
> function calls afais. So where are the java codes, and how does the
> driver call them?

The Java code is in the JDBC driver, that is loaded from the
system. In the case of embedded HSQLDB, the JDBC driver is bundled
with LibreOffice and is handled in the build system by
external/hsqldb. It is installed as instdir/program/classes/hsqldb.jar
You'll find the source in workdir/UnpackedTarball/hsqldb/

There is also instdir/program/classes/sdbc_hsqldb.jar; I think this
contains the hack to redirect HSQLDB writes directly into the
in-memory ZIP structure of the ODB instead of to a file. The actual
source code to that is in connectivity/source/drivers/hsqldb/Storage*
and connectivity/com/sun/star/sdbcx/comp/hsqldb

The embedded HSQLDB is mostly just the JDBC driver, with some extras
specific to HSQLDB in connectivity/source/drivers/hsqldb

(In the case of HSQLDB, "JDBC driver" is a bit of a misnomer, since
JDBC is the native API of HSQLDB.)

-- 
Lionel