Re: Avoiding explicit addDataType calls for PostGIS

Hi, Kris,

On Wed, 6 Oct 2004 11:40:31 -0500 (EST)
Kris Jurka <books(at)ejurka(dot)com> wrote:

> > The second approach would add a "wrapper" parameter to the postgresql
> > driver url. This parameter contains comma-separated class names that all
> > implement a common interface. On every connect() call, the driver would
> > then instantiate all of those classes [1], and then pass
> > the created PGConnection to those classes, before return.
>
> The problem with the driver instantiating any classes from strings is that
> classloaders for the driver may not be able to load the given classes even
> though user code could.
>
> Note that PGConnection.addDataType(String type,
> String classname) is deprecated for addDataType(String type, Class klass)
> to avoid exactly this problem.

Is the opposite problem possible? I think of the driver class loader be
able to reach the driver extension, but not the user code class loader.

> That said I understand your frustration and I think your first approach is
> rather clever. Let's see what other people have to say about the other
> approaches and the above limitation.

My driver wrapper approach even has the advantage that it can work with
different class loaders, as you can arbitrarily code whatever you want.

> > (BTW, is it possible that there is no license file in pg-jdbc cvs?)
>
> Yeah, it used to be part of the main server tree and used that
> license, but now that it's out on its own I'll see about adding one. A
> plain BSD license in case you were wondering.

I thought it to be like that. However, adding the license file to the
tree will simply remove all clues.

Thanks,
Markus Schaber

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