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Posted to ojb-user@db.apache.org by ol...@ppi.de on 2003/05/07 08:05:50 UTC
Writing own SequenceManager
Hello,
I want to write my own sequence manager. It shall work as follows:
The value returned by getUniqueLong(field)contains a 16-bit
classId (unique for the specified class) on the most significant
bits. The value of the remaining 48 bits is the one higher than
the maximum available in the table of the specified class.
As far as that maximum is concerned, I want to
do it similarly as the SequenceManagerInMemoryImpl does.
For this purpose, it would be convenient to have access to
the private methods of SequenceManagerHelper, in particular
private static long getMaxIdForClass
What do you think: Could be make that public?
Do you like that idea?
Has anybody done something similar?
For those of you who are interested:
I am going to exploit the fact that the real class is included
in the uid in the PersistenceBroker: I write
my own implementation for it which extends PersistenceBrokerImpl,
but I overide getObjectByIdentity as follows:
public Object getObjectByIdentity(Identity id) throws
PersistenceBrokerException
{
if (id.getObjectsRealClass() == null)
{
short ci = getClassId(id);
Class realClass = classToIdMapper.idToClass(ci); // classToIdMapper is a
helper
id.setObjectsRealClass(realClass); // hint to search in the right
table.
}
return super.getObjectByIdentity(id);
}
This leads to a significant improvement when traversing references to
very polymorphic classes.
Olli
--
Dr. Oliver Matz
ppi Media GmbH
Deliusstraße 10
D-24114 Kiel
phone +49 (0) 43 1-53 53-422
fax +49 (0) 43 1-53 53-2 22
email mailto:oliver.matz@ppi.de
web www.ppi.de
Re: Writing own SequenceManager
Posted by Armin Waibel <ar...@code-au-lait.de>.
Hi Oliver,
> the private methods of SequenceManagerHelper, in particular
> private static long getMaxIdForClass
> What do you think: Could be make that public?
No problem, is in CVS now.
> This leads to a significant improvement when traversing references to
> very polymorphic classes.
Sounds like a smart improvement. What about the
performance gain?
regards,
Armin
----- Original Message -----
From: <ol...@ppi.de>
To: <oj...@db.apache.org>
Sent: Wednesday, May 07, 2003 8:05 AM
Subject: Writing own SequenceManager
Hello,
I want to write my own sequence manager. It shall work as follows:
The value returned by getUniqueLong(field)contains a 16-bit
classId (unique for the specified class) on the most significant
bits. The value of the remaining 48 bits is the one higher than
the maximum available in the table of the specified class.
As far as that maximum is concerned, I want to
do it similarly as the SequenceManagerInMemoryImpl does.
For this purpose, it would be convenient to have access to
the private methods of SequenceManagerHelper, in particular
private static long getMaxIdForClass
What do you think: Could be make that public?
Do you like that idea?
Has anybody done something similar?
For those of you who are interested:
I am going to exploit the fact that the real class is included
in the uid in the PersistenceBroker: I write
my own implementation for it which extends PersistenceBrokerImpl,
but I overide getObjectByIdentity as follows:
public Object getObjectByIdentity(Identity id) throws
PersistenceBrokerException
{
if (id.getObjectsRealClass() == null)
{
short ci = getClassId(id);
Class realClass = classToIdMapper.idToClass(ci); // classToIdMapper
is a
helper
id.setObjectsRealClass(realClass); // hint to search in the right
table.
}
return super.getObjectByIdentity(id);
}
This leads to a significant improvement when traversing references to
very polymorphic classes.
Olli
--
Dr. Oliver Matz
ppi Media GmbH
Deliusstraße 10
D-24114 Kiel
phone +49 (0) 43 1-53 53-422
fax +49 (0) 43 1-53 53-2 22
email mailto:oliver.matz@ppi.de
web www.ppi.de
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