many-to-one proxy properties not initialising

rbrady · **Joined:** Mon Oct 03, 2005 6:03 am **Posts:** 4

Hi there,
I'm having a problem with many-to-one proxy. The class is lazy loading and a proxy is being returned, however, all the proxy values including the identifier are never initialised when I request the proxy object. I looked at the proxy in a debugger and it looks like:

Have I configured something incorrectly? I thought it might be to do with unsaved-value or the definition of my Equals or hashcode, but I've written them using business key equality and using the class properties instead of the class field values as described in 'Hibernate in Action' ... still no joy :(

How do I get the proxy to initialise when values are requested?
Any help appreciated,

Ronan

My class mappings

Code:

///////////////////////////////////////////
// CurrencyInfo mapping
<class 
    name="com.luzern.ccc.dal.CurrencyInfo, CCCDbLib" 
    table="tblSalesCurrency"    
    lazy="true"
>

    <id
        name="Id"
        type="Decimal"
        column="CurrencyID"
        unsaved-value="0"
    >
        <generator class="identity" />
    </id>

   <property
        name="Name"
        type="System.String"
        column="CurrencyName"
        length="50"
    />

   <set name="SalesChannels" table="tblSalesChannel" cascade="all-delete-orphan" lazy="true"> 
        <key>           
         <column name="CurrencyID"/>            
        </key>
       <one-to-many class="com.luzern.ccc.dal.SalesChannel, CCCDbLib"/>
    </set>
   </class>

</hibernate-mapping>
///////////////////////////////////////////
// End CurrencyInfo mapping
///////////////////////////////////////////

///////////////////////////////////////////
// Start SalesChannel mapping
///////////////////////////////////////////

<class 
    name="com.luzern.ccc.dal.SalesChannel, CCCDbLib" 
    table="tblSalesChannel"    
    lazy="true"
>

    <id
        name="Id"
        type="Decimal"
        column="SalesChannelId"
        unsaved-value="-1"
    >
        <generator class="identity" />
    </id>

 
    <many-to-one 
      name="CurrencyInfo" 
      class="com.luzern.ccc.dal.CurrencyInfo, CCCDbLib" 
      column="Currency"       
      not-null="true"/>   
    
    
  </class>

</hibernate-mapping>

///////////////////////////////////////////
// End SalesChannel mapping
///////////////////////////////////////////

[/b]

xor · **Posted:** Mon Oct 03, 2005 7:30 am

For proxies to work, persistent properties of proxied class must be virtual. Is it true for your code?

rbrady · **Joined:** Mon Oct 03, 2005 6:03 am **Posts:** 4

Thanks for that Andrew.

Twas exactly what I was doing wrong.

/Ronan

ChrisHibbert · **Joined:** Mon Mar 20, 2006 7:40 pm **Posts:** 8

I'm a long time OO developer, and have been using Java for years. I've been writing Hibernate code for a few months, and I seem to have been bitten by this same bug in a few places, but I don't know how to interpret the terminology of the solution that xor provided. I have some fields that I can see in the debugger (in Idea) have had their proxies loaded, but when I try to access the values that are clearly loaded in the proxies, I get null instead.

"virtual" isn't an attribute that I can declare for a Java field or method. I don't see a place to declare "virtual" in the hbm.xml. What do you mean by property? Where do you declare this?

This forum thread

http://forum.hibernate.org/viewtopic.ph ... 41#2297041

uses the same terminology, and it was apparently just as enlightening for jnapier as for you, but I'm not getting it.

The only thing I've been able to make work is declaring the field to be outer-join=true in the parent class. I shouldn't have to do that to get loaded proxies to provide access to the state they've already loaded.

Thanks.

xor · **Posted:** Tue Mar 21, 2006 4:37 am

Chris, we are talking about NHibernate, i.e. Hibernate for .NET Framework. So you just a bit missed with forum's thread. :)