Hello,
as this is my first contribution to an open source project, please tell me if I'am writing to much details in this list.
Christophe Lombart wrote:
Yes I did, but according to the request of Oliver, my email was just a first draft of the proposal.Sandro,
Did you check what Oliver did ? I'm working with him in order to see
I looked especially at JcrNodeObjectValueConverter. It looks good, but I would like to be more type safe. I think this would make it easier to browse through the content (e.g. with the Day's Content Explorer) and maybe to work with the content (setProperty, getProperty).
BTW: After I checked it again today I think you are right, the Struts bean introspection is not neccessary, the java.bean.* tools should be fine.
what we can do together. I hope to make a proposal to this mailing asap.Does node type management mean for you to maintain the mapping between the two structures (use case e)? If yes, at the moment I don't have an idea how to handle that, because I think it is not an easy part. This is why I would think about it when I have done some basic work. As a pragmatic solution maybe we can do the maintenance of the mapping without an automatism at the first step.
Your ideas are interesting and we are working in the same way. If you have not a lot of time, please check what Oliver did and give us your point of view.
Giving your own point of view is already a great contribution.
What about the JCR node types ? Node type management seems for myself the most unclear area when we are speaking about mapping java beans to a JCR repo.
It should be nice to give some flexibilty : either the object gragh is serialised in a unstructurred set of nodes or is serialised by following mapping rules defined in a file (something like in ORM tools : OJB, ....)As I have no idea yet what the advantage of the mapping rules is, I would vote for unstructured nodes.
What do you think about that ?
Best regards,
Sandro
Christophe
Sandro B�hme wrote:
Hello,
the basic idea is, to use the bean class structure as the master and create the nodetypes according to the bean classes. E.g it could be possible to create the beans out of an uml tool.
At the moment I can imagine the following use cases:
a) creating the nodetype structure at design time
b) reading beans from nodes at runtime
c) writing beans to nodes at runtime
d) persist beans to the persistance layer
e) maintaining the bean structure (rename beans or properties, delete beans or properties, change the type of the bean or property...)
I think use case e) need some definition (specification like xdoclet,... or a user interface) what to do with data whose type has changed. So I would think about further until the basics work.
I'am sorry in advance, because I have not that much spare time, so it will need some time until I can complete some tasks. But I will do my best.
First I would like to create a textual mapping between JCR features and Java features like:
Mixin = Interface
Node Type Name = Class Name
isMixin = this.getClass().isInterface()
...
some initial ideas:
a) Maybe we can use the Struts bean introspection to check the beans, create the nodetypes out of that information and registering them. Too bad, that creation and registering of nodetypes is not part of the JCR-spec :-(.
b) With
bean class name equals node type name and
bean property name equals child node name or property name
it should be possible to use the JCR introspection to get the node values.
Maybe we can provide the data by a generic
Object getProperty(Object beanObject, String propertyName); method.
c) Similar to b) Maybe we can set the data by a generic void setProperty(Object beanObject, String propertyName); method.
d) We could provide two save methods like saveBean(Object beanObject) and saveBeanProperty(Object beanObject, String beanProperty).
When I thought about mapping a bean class graph to a persisting graph I thought this problem should be already solved some years ago by object databases. So I will do some research if there are some tools/concepts which will work in our use cases.
What do you think about all this?
Best regards,
Sandro
Oliver Kiessler wrote:
On Fri, 18 Mar 2005 21:39:30 +0100, Christophe Lombart <[EMAIL PROTECTED]> wrote:
Sandro B�hme wrote:
Hello Christophe,
at the jackrabbit mailing list you said, you may want to implement a mapping layer between java objects and node objects. If there is nothing yet started in this direction I would try to implement a first version of it. If there is already some work done, I would like to participate, if you want.
Best regards,
Sandro
Olivier Kiessler is working on that (see on http://www.techblogs.de/roller/page/okiess). You are welcome to join us. It should be nice to see ASAP a proposal on that topic.
Yes, I have written some code for JCR object persistence/mapping. It is not officially available yet, but if you are interested to join in or have a look at it, you are very welcome. Let me know and I'll send you the source code.
regards, oliver
