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TopLink support for JDO?

12525Jun 24 2002
Hi,

I'm new to TopLink and am wondering what the status of JDO support is in 4.6. I can see that there is a JDO example, and that the RELNOTES indicate JDO support. But the level of spec compliance and JDO specific tools in TopLink are not documented AFAIK.

Comments

12525
I'm beginning to suspect that TopLink 4.6 support of JDO is a "technology preview" and not a JDO 1.0 release.

Could someone at Oracle give a statement as to the future of TopLink JDO and TopLink in general?

Thanks.
12525
I finally found the javadocs in the TopLink 4.6 distribution. From these, plus from the examples, it seems to me that the TopLink JDO 1.0 support is partial.

They do provide partial implementations to most of the JDO interfaces in javax.jdo package. The one exception is javax.jdo.InstanceCallbacks. What I mean by partial is that some required methods are no-ops (no operation). No-ops do nothing and return null or zero depending on their return type.

They don't support the JDO query language. You can use their implementation of javax.jdo.Query to create a query using SQL, TopLink query language, or EJBQL.

They don't support the enhancer. The enhancer is controversial, therefore some people see this as a good thing.

I ran a little program to display the results of PersistenceManagerFactory.supportedOptions() for TopLink.

SUPPORTED OPTIONS
javax.jdo.option.NontransactionalRead
javax.jdo.option.ArrayList
javax.jdo.option.HashMap
javax.jdo.option.Hashtable
javax.jdo.option.LinkedList
javax.jdo.option.ArrayList
javax.jdo.option.TreeMap
javax.jdo.option.TreeSet
javax.jdo.option.Vector
javax.jdo.option.Map
javax.jdo.option.List
javax.jdo.option.Array

UNSUPPORTED OPTIONS
javax.jdo.query.JDOQL
javax.jdo.option.RestoreValues
javax.jdo.option.NullCollection
javax.jdo.option.NontransactionalWrite
javax.jdo.option.TransientTransactional
javax.jdo.option.RetainValues
javax.jdo.option.NonDatastoreIdentity
javax.jdo.option.Optimistic
javax.jdo.option.DatastoreIdentity
javax.jdo.option.ApplicationIdentity

I'm not sure why the javax.jdo.query.JDOQL option even exists. As I understand it support for the JDOQL is mandatory, not optional. But maybe this is a versioning thing. That is, maybe JDO 2.0 will allow implementations to provide JDOQL 1.0 and/or JDOQL 2.0. Just a guess.

Hope this helps.
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Locked on Jul 24 2002
Added on Jun 24 2002
#application-development-in-java, #jdeveloper-and-adf
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