Hi Sahoo,
From the container point of view, how does redeployment happen?
By section 5.3 of the spec (footnote 32) there can only be one entity
manager factory per persistence unit. This means that when a create is
called, we need a way to determine if something is a redeploy or an
initial deploy.
Looking at the last paragraph of section 7.1.1 of the spec, it says
that createContainerEntityManagerFactory() is the way to cause a
redeployment to occur. If only the name is provided, how does the
persistence provider distinuguish between an initial deploy and a
redeploy?
We thought of using the ClassLoader as a way to uniquely identify
things, but the spec does not guarantee that the class loader will be
the same on each call, so the ClassLoader is eliminated as a way to
identify things.
-Tom
Sanjeeb Kumar Sahoo wrote:
>Hi Tom,
> I really don't understand why does provider care about the name?
>Container is responsible for resolving PU names and calling
>provider.createEMF() appropriately. Container calls emf.close() during
>redeployment. So would you mind explaining why TopLink needs to know
>what is the name of the PU?
>
>Thanks,
>Sahoo
>Tom Ware wrote:
>
>
>
>>Sahoo,
>>
>> I just had a quick chat with Mike Keith. And he is hoping we can
>>come up with some ideas about how to uniquely identify the PU (since
>>the name is not unique as mentioned below). When we come up with a
>>good solution, it will be brought up as part of the spec discussions.
>>
>> Our initial suggestion is that the container provide some kind of
>>identifier to the persistence provider in the PersistenceUnitInfo.
>>This could possibly be a String pointing to the location of the
>>persistence unit, a URL, or some other String that uniquely identifies
>>the persistence unit when used in conjunction with the name.
>>
>>What do you think? Do you have any suggestions?
>>
>>Thanks,
>>Tom
>>
>>Tom Ware wrote:
>>
>>
>>
>>>The problem is that based on the information available, there is no
>>>way to uniquely identify the PU and since the spec says that if we
>>>call this method with the same PU, we have to redeploy, there is know
>>>way to know which path to take. I have been told the spec comittee is
>>>discussing this.
>>>
>>>-Tom
>>>
>>>Sanjeeb Kumar Sahoo wrote:
>>>
>>>
>>>
>>>
>>>
>>>>Hi Tom,
>>>>I don't know what is the confusion here. Any way, can't we at least
>>>>fix such that PU names does not have to be unique across the JVM?
>>>>
>>>>Thanks,
>>>>Sahoo
>>>>tware_at_dev.java.net wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>https://glassfish.dev.java.net/issues/show_bug.cgi?id=78
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>------- Additional comments from tware_at_dev.java.net Thu Dec 8
>>>>>13:57:26 +0000 2005 -------
>>>>>The spec will be providing clarification about this issue. We will
>>>>>make changes when the new information is available.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>
>
>
--
Tom Ware
Principal Software Engineer
Oracle Canada Inc.
Direct: (613) 783-4598
Email: tom.ware_at_oracle.com