David Haraburda wrote:
> Hi all,
>
> I have written a patch to make Tomcat work with Tyrex 1.0. Here's a
> summary of the new classes/code and how it all works. I apologize for
> the length of this post, the explanation is necessary I feel...
>
> New class org.apache.naming.factory.TyrexFactory:
>
> Tyrex now has the idea of a TransactionDomain, which manages resources
> and transactions and is configured through an XML config file. In order
> to instantiate a TransactionDomain instance, the class must know two
> things: the location of the domain config file, and the name of the
> domain to lookup in the file. The way I've set it up, these two string
> configuration parameters must be present in the java:comp/env
> namespace. The TyrexFactory is an abstract superclass that provides a
> method to lookup these configuration parameters and create the
> TransactionDomain. The two subclasses of this abstract class are...
>
> New/modified class: org.apache.naming.factory.TyrexTransactionFactory:
>
> This factory simply uses the TransactionDomain to create a
> javax.transaction.UserTransaction.
>
> New class org.apache.naming.factory.TyrexResourceFactory:
> (this replaces TyrexDataSourceFactory)
>
> Tyrex now also has the idea of resources, of which now there are only
> two "flavors" right now: JDBC DataSources and JCA connectors. Since
> the configuration of these resources must be done in Tyrex's domain XML
> config file, this factory simply returns the resource with the specified
> name -- it is up to the user know what to do with the Object returned.
>
> Here's an example of how Tyrex would be setup for a simple JDBC
> datasource. Let's say you have a domain-config.xml file, with a domain
> named "my-domain", which has a resource named "my-db", which is a JDBC
> datasource (see Tyrex docs for more info). In the server.xml file, we
> would need to specify two environment parameters:
>
> <Environment name="tyrexDomainConfig" type="java.lang.String"
> value="domain-config.xml"/>
> <Environment name="tyrexDomainName" type="java.lang.String"
> value="my-domain"/>
>
> and a resource:
>
> <Resource name="my-datasource" auth="Container"
> type="tyrex.resource.Resource"/>
> <ResourceParams name="my-datasource">
> <parameter>
> <name>name</name>
> <value>my-db</value>
> </parameter>
> </ResourceParams>
>
> This would all need to go under a <Context> element (I made the two
> config strings global environment elements, and created ResourceLinks
> instead).
>
> Now, the domain-config.xml file is placed where the classloader can use
> getResource() to find it (so, WEB-INF/classes is a good place), and
> everything should be ready to go. You can now do:
>
> InitialContext initCtx = new InitialContext();
> DataSource ds = (DataSource)
> initCtx.lookup("java:comp/env/my-datasource");
> Connection conn = ds.getConnection();
> ... etc
>
> in your user-level code. Tyrex is still the default factory for
> UserTransaction, so lookups on java:comp/env/UserTransaction work.
>
> There are a few caveats:
>
> (1) This is kind of a pain, but it's the way Tyrex 1.0 works. This way
> provides a lot of flexibility, without too much extra hassle. If these
> changes are made, however, a HOWTO is probably needed. I can put one
> together.
> (2) For this to work, Tomcat now needs to be able to load the Tyrex
> classes, and any classes it uses. This means the tyrex jar and all
> other jars included in the Tyrex distribution need to go in common/lib
> (that includes JTA, OTS-JTS, and Xerces). Furthermore, Tyrex needs some
> JARs that it doesn't include in its distribution: the Castor XML jar,
> and the Log4J jar. This is six jars that need to be in common/lib for
> Tyrex to work. This kind of stinks as well.
>
> Obviously there are probably a few kinks that need to be worked out, but
> I've tested what is attached and it seems to work pretty well.
>
> I've attached a cvs diff, as well as the two new files that are needed.
> These two new classes both go in the org.apache.naming.factory package.
> (remember TyrexDataSourceFactory needs to be removed)
>
> Feedback/suggestions on my code is appreciated. I'd like to see Tyrex
> 1.0 integrated with Tomcat fairly soon, so I'm prepared to make whatever
> changes I need to in order to get the patch committed.
For the transaction stuff to work properly, don't you need a valve also
to bind/unbind the Tyrex context ?
Or is this only needed if you would want your transaction to last more
than one request ?
I'm +1 for the patch. We'll need to add detailed instructions on how to
use it. Also, the JARs won't ship with Tomcat (it's just too much).
Remy
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