Hi,
great, this sound like it could solve my problem. I already used the "standard"
external resource mechanism via some text-file, but now I want to try to share
read access to a SQL database among some TAEs in a processing pipeline.
Does anyone know "best practices" for doing this? So far each TAE that needs
read access to the database has its own set of connection parameters and needs
to initialize a new connection. My first idea was that defining this as external
resources might do the trick.
Thanks,
Christoph
Adam Lally schrieb:
On Tue, Jul 1, 2008 at 10:44 AM, Christoph Büscher
<[EMAIL PROTECTED]> wrote:
Hi,
I have a few questions about binding to external resources that are no file
resources. The documentation mentions the option to use a
"customResourceSpecifier" as described in
http://incubator.apache.org/uima/downloads/releaseDocs/2.2.2-incubating/docs/html/references/references.html#ugr.ref.xml.component_descriptor.custom_resource_specifiers
I would like to use the resource mechanism to bind to an interface for read
access to a database. The database connection parameters would be parameters
in the "customResourceSpecifier".
I have a few questions concerning this.
1. How do I include a custom resource specifier in e.g. a CPEs resource
binding? It's not exactly clear to me from the documentation, but I would
try something like:
<externalResource>
<name>MyDBResource</name>
<description>a resource that provides read access to a
database</description>
<customResourceSpecifier>
pathToCustomresourceSpecifier/myCustomResourceSpecifier.xml
</customResourceSpecifier>
</externalResource>
Can I find examples for the correct syntax here somewhere in the
documentation?
It should be possible to do what you want (In his email, Michael is
referring to another use for custom resource specifiers, but they
should work for this as well).
This is basically right, but you need to put the
<customResourceSpecifier> inline, like this (excuse my lack of
indentation):
<externalResource>
<name>[String]</name>
<description>[String]</description>
<customResourceSpecifier xmlns="http://uima.apache.org/resourceSpecifier";>
<resourceClassName>[Java Class Name]</resourceClassName>
<parameters>
<parameter name="[String]" value="[String]"/>
<parameter name="[String]" value="[String]"/>
</parameters>
</customResourceSpecifier>
</externalResource>
Documentation for the <externalResouceElement> is in
http://incubator.apache.org/uima/downloads/releaseDocs/2.2.2-incubating/docs/html/references/references.html#ugr.ref.xml.component_descriptor.aes.primitive
(scroll down to 2.4.1.11). I just replaced the
<fileResourceSpecifier> with the custom resource specifier.
2. The documentation mentions the implementation class must implement the
"Resource" interface. Is there any existing implementation of "Resource"
that is safe to extend to use in an external resource binding?
You can extend Resource_ImplBase, and just override the initialize
method. There's a trivial example of a custom resource in the
uimaj-core unit tests - org.apache.uima.impl.SomeCustomResource.
-Adam
