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From "Thomas Fox (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TORQUE-343) Implement a central registry for peerImpls like the registry for managers
Date Thu, 16 Jun 2016 08:10:05 GMT

    [ https://issues.apache.org/jira/browse/TORQUE-343?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15333324#comment-15333324
] 

Thomas Fox commented on TORQUE-343:
-----------------------------------

You can already dynamically extend and exchange the PeerImpls by SomePeer.setSomePeerImpl()
method. It is already kind of a distributed registry. Would the SomePeers query the registry
instead of storing the PeerImpls locally?

Also a central registry has the problem of type safety. The PeerImpls are currently generic,
yet there are some methods which are generated for some PeerImpls but not for others (e.g.
retrieveByPK(String, int, String, Integer, Byte, Short, Long, Double, Double, Date) is generated
for BaseMultiPkPeerImpl but not for BaseAuthorPeerImpl) which would require explicit casts
if the type of the returned PeerImpl is not known.

Where would the registry be used? If you can point to some use cases, I could better make
up my opinion.


As for moving the buildCriteria(obj) to the RecordMapper, I'd rather not do this. Currently,
a RecordMapper has the single purpose to map a database record to the Object. So if one has
as strange database structure one has to read, one can easily implement the RecordMapper interface
to perform the mapping manually. See e.g. the clases in org.apache.torque.om.mapper. Moving
other functionality into this interface would impede this function in my opinion.
However, I'd rather suggest to cerate another object which is responsible for creating the
other way round (object to database) (name suggestion: ...Selector) which then would contain
the buildCriteria(Object) method (as well as perhaps the other build...CriteriaMethods). However
this would again increase the number of created classes, so I am not sure whether this does
not add too much complexity.

As for moving the buildCriteria(obj) to the table map: The table map is currently not a generated
class. How would you accesss the relevant getters for the data object there?

Again, can you provide a reson why it would be favorable to move the buildCriteria(obj) method?

> Implement a central registry for peerImpls like the registry for managers
> -------------------------------------------------------------------------
>
>                 Key: TORQUE-343
>                 URL: https://issues.apache.org/jira/browse/TORQUE-343
>             Project: Torque
>          Issue Type: Improvement
>          Components: Runtime, Templates
>    Affects Versions: 4.0
>            Reporter: Thomas Vandahl
>            Assignee: Thomas Vandahl
>             Fix For: 4.1
>
>
> I'd like to suggest a central registry for peerImpl-objects which can be queried by the
Persistent class it is responsible for. This would allow reusing and extending the peer objects
dynamically as well as giving them some kind of life-cycle.
> The main method would be similar to this:
> {code:java}
> public <T> BasePeerImpl<T> getPeerFor(Class<T> persistentClass)
> {
>     return peerRegistry.get(persistentClass);
> }
> {code}
> I would also like to suggest moving the buildCriteria(obj) method to the RecordMapper
or the TableMap class. This will further reduce the amount of code that needs to be generated.
> If the idea is received well, I'll come up with a proposal.



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