Hi,
I am writing a class which is supposed to cache the data from all the master tables in my application in the form of an arraylist of value objects so that i can use this to populate the drop down in jsp using struts tag.
I am using hibernate to query the database and return me a arraylist.
But the problem is that i am required to create a seperate VO for each master table who data i want to cache.

eg CurrecyVO refers mst_currency which has code and desc.

All my master tables have just the code and desc. I want to know a way by which i can use the same value object for all the tables. This value object will store the code and desc by getting it from appropriate table.
I want to avoid the redundancy of create similar value objects for different master tables. Is it possible to do this with hibernate , please comment.

Awaiting ur response.

select new ValueObject(o.code, o.desc) from MyObject o

sorry, I didnt understand your reply properly, can your please clarify

This is my ".hbm.xml" file

<hibernate-mapping>
<class name="com.statestr.fxmm.pbg.domain.RefCalcMethodVO" table="REF_CALC_METHOD">
<id name="code" column="CALC_METHOD_CD">
<generator class="hilo"/>
</id>
<property name="desc" column="CALC_METHOD_DESC"/>
</class>

</hibernate-mapping>

and my query is

Query query = session.createQuery("select calc from RefCalcMethodVO as calc");

Now as per your reply

"select new ValueObject(o.code, o.desc) from MyObject o"

what will be ValueObject and MyObject in my case.

How will i point my hbm.xml to different tables.

Use a ValuePair for the model when generating/populating the dropdown.
Michael is saying, convert this:


to



This will create a list of ValueObjects populated with the value/key pair. This can be safely cached by your application. All you need to do is create the DTO object ValueObjects, eg, No changes to the mapping(s).

i tried the code above but gives me a error

net.sf.hibernate.QueryException: class not found: ListVO

[SELECT new ListVO(calc.calcMethodCd, calc.calcMethodDesc) FROM com.statestr.fxmm.pbg.domain.RefCalcMethod AS calc]

where ListVO is a normal class having code and desc as it members with getter and setter. Also it has a constructor accepting two object parameters.

it is not able to find ListVO probably cause i have not mentioned it anywhere. Where do i specify it?

How do i get around this problem. ?

It expects me to give the full path of the ListVO

SELECT new com.statestr.fxmm.pbg.domain.ListVO(calc.calcMethodCd, calc.calcMethodDesc FROM RefCalcMethod AS calc

is there a way to avoid giving the path.

Map ListVO in your mapping file. It's not necessary to map it to a table.

Do i have to create a ListVO.hbm.xml for this Value object (ListVO)

I have added a line in my hibernate.cfg.xml fiel

<mapping resource="com/statestr/fxmm/pbg/domain/ListVO.hbm.xml" />

and in the listVO.hbm.xml file i have defined
------------------------------------------------------------
<hibernate-mapping>

<class name="com.statestr.fxmm.pbg.domain.ListVO"/>
</hibernate-mapping>
------------------------------------------------------------

But it gives me error

Caused by: org.xml.sax.SAXParseException: The content of element type "class" is incomplete, it must match "(meta*,(cache|jcs-cache)?,(id|composite-id),discriminator?,(version|timestamp)?,(property|many-to-one|one-to-one|component|dynamic-component|any|map|set|list|bag|idbag|array|primitive-array)*,(subclass*|joined-subclass*))".


so i guess something else is required , which is mandatory and i am not providing it. please help

If you look at the DTD of the xml file you will see that the <id> tag is required.

Just put in :

Or :

When using Hibernate Tools.

Thanks a lot

or you could have just done something like this: