Two design problems..

katching · **Joined:** Tue Mar 24, 2009 2:26 pm **Posts:** 1

Hi

I use Hibernate 3 with annotations and I have two design problems I have trouble finding the answer to..

First:
I would like to map a collection (private Map<String, String> whatever) which does not correspond to any whatever class, what is the best way to do this? Im using annotations and would appreciate a code example.

Second:
I have a BaseEntity class in which I would like to have "Date createdDate" and "Date lastUpdated" what is the best way to do this. I have tried using a listener but could only get it to work on creation date but I would if possible like to use a simpler solution. Again a code example using annotations would be appreciated.

Thanks!

ethnarch · **Joined:** Tue Aug 01, 2006 9:24 pm **Posts:** 120

Code:

First: 
I would like to map a collection (private Map<String, String> whatever) which does not correspond to any whatever class, what is the best way to do this? Im using annotations and would appreciate a code example. 

What do you mean by this (what is the collection for)?

If it's not for persisting any data you can just use the @Transient annotation

Code:

Second: 
I have a BaseEntity class in which I would like to have "Date createdDate" and "Date lastUpdated" what is the best way to do this. I have tried using a listener but could only get it to work on creation date but I would if possible like to use a simpler solution. Again a code example using annotations would be appreciated. 

The listener seems like the best solution.

However in the past I have implemented an interface on all of my entities. And used a manager layer that would always pass my entities to methods in a superclass that all my managers extended. This only works when you are starting from scratch and your persisting one class at a time.

I would be interested in any other solutions to this problem also.

nordborg · **Posted:** Wed Mar 25, 2009 5:24 pm

Quote:

I would like to map a collection (private Map<String, String> whatever) which does not correspond to any whatever class, what is the best way to do this? Im using annotations and would appreciate a code example.

You'll need to use the Hibernate extended annotation for this since it is not possible with standard JPA annotations. Check http://www.hibernate.org/hib_docs/annot ... -extratype for a (somewhat complex) example. It should be possible to use a Map<String, String> also. There are more examples in the documentation for xml-based configuration: http://www.hibernate.org/hib_docs/v3/re ... s-ofvalues