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From Rick Hillegas <Richard.Hille...@Sun.COM>
Subject Re: Proposal to change Derby's public api for XADataSource and ConnectionPoolDataSource
Date Mon, 15 May 2006 22:51:21 GMT
Thanks for forwarding this, Kathey.

Regards,
-Rick

Kathey Marsden wrote:

> Rick Hillegas wrote:
>
>> Dear Derby users,
>>
>> 0Please read this message if you work on an application server or in 
>> an application layer which cares about distributed transactions 
>> and/or pooled connections.
>>
>> Right now the inheritance graph for Derby's DataSources does not 
>> mirror the corresponding graph of interfaces in javax.sql. Derby's 
>> DataSources are classes which you will find in Derby's published 
>> javadoc for the package org.apache.derby.jdbc. In particular, Derby's 
>> XADataSources and ConnectionPoolDataSources implement the DataSource 
>> interface. This is so even though the javax.sql.XADataSource and 
>> javax.sql.ConnectionPoolDataSource interfaces themselves do not 
>> extend javax.sql.DataSource.
>>
>> We believe this is confusing, particularly to developers who are 
>> trying to build applications which easily port across different 
>> vendors' JDBC implementations. We propose to rework the hierarchy of 
>> classes in org.apache.derby.jdbc so that our XADataSources and 
>> ConnectionPoolDataSources no longer implement javax.sql.DataSource. 
>> We propose to expose this change in Derby 10.2.
>>
>> However, we do not want to make this change if it will break existing 
>> applications. Please let us know if you think this will break your 
>> app server or other Derby-powered application.
>>
> I got this feedback from someone supporting an app server.
>
> <quote>
> I think its a risky change if you ask me.  You don't know if users  
> already depend on such behavior.  Also, not sure i understand the 
> statement "We believe this is confusing, particularly to developers 
> who are trying to build applications which easily port across 
> different vendors' JDBC implementations."  Can you explain more?  BTW, 
> Oracle does implement the javax.sql.DataSource, so you are not hte 
> only one.  DB2 doesn't though.
>
> We  depend on having your PooledDS be instance of 
> ConnnectionPoolDataSource and your XADS be instance of  
> javax.sql.XADataSource and nothing else.
> Saying that however, i don't know what our  stack products are doing 
> with the Derby DataSources specially if they have special Derby logic, 
> so my statement is only for our base.
> </quote>
>
>
> Kathey
>
>
>


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