Yeah I think it will be very similar to what you have done or what I have tried to do.
Alex On 3/27/07, David Jencks <[EMAIL PROTECTED]> wrote:
On Mar 27, 2007, at 11:28 AM, Alex Karasulu wrote: Ole, On 3/21/07, Ole Ersoy <[EMAIL PROTECTED]> wrote: > Hey Guys, > > Just wanted to see if anyone had any thoughts on handling updates > to Java beans (Service Data Objects - but basically the same thing) > persisted with ADS. > > With Service Data Objects we create a datagraph that is then > disconnected > from it's persistence source and we can mutate it. Then later we want > to > persist the graph. Each object in the graph has a change summary, that > stores the fields that were updated. This change summary is very interesting. I had experimented with something similar which David Jencks did not like too much. Basically the modifier pattern was being used to track modifications to attributes of entities. It was tracking the set of modify add, remove, and replace operations to perform on each attribute. What I didn't like was that you were keeping track of the modifications outside the POJO-like data object itself in (IMO) very hard to use helper objects, and you didn't write a framework. I took essentially the same idea and came up with something pretty similar to jpa/jdo, where you have things that look like POJOs to the outside world, but inside they keep track of how they relate to what's in the persistent store. The main differences to the ideas of jpa are that I don't support disconnection and you have to do the enhancement yourself. In a non-locking not-transactional environment I'm not sure exactly what disconnection means so this might not really be accurate. IIRC this stuff is all in the sandbox/triplesec-jacc2 branch. In the past I've tried to describe the kinds of ldap <> object mappings I need and support in my framework but haven't understood from Ole whether the DAS will offer similar capabilities. thanks david jencks > This makes it possible to only update objects that have been changed, > and > we only need to update the fields that were changed. Exactly this is what I was doing in this one admin API I had in triplesec. > However, I think the DirContext will overwrite the entire > object during the bind operation, rather than updating specific fields > on the object. Hmmm with heirarchical services in JNDI you should not be using bind(). You should be using the createSubcontext() and modifyAttributes() methods instead. You might want to go through the JNDI tutorial for LDAP just to get a good feel for how to work with non-flat namespaces using JNDI. Namely with LDAP you don't need to rebind the object with a modification to an attribute. This is what the modify operations are for. http://bsd.cs.cofc.edu/Java/Javadocs1.5/api/javax/naming/directory/DirContext.html#modifyAttributes(javax.naming.Name , int, javax.naming.directory.Attributes) > Initially I was thinking that the object's attributes (primitive > properties - not references to other objects) > would be serialized and made into directory attributes. But I think a > LDAP ObjectClass schema that corresponds to the > object's class (The class of the object we are persisting) would have to > be generated and stored along with the instance. > > This might lead to performance improvments, if doable...? > > Thoughts? Hmmm I think some of your premisses in this question may be due to considering the use of bind() instead of using modifyAttributes() and createSubcontext(). If you use these methods I think there is no further preformance issue to consider. WDYT? Alex
