RE: afterLookUp() gets called before initialisation of other objects.

[Cory Prowse]

I'll just chime in here and say that I too have noticed that some of the
setters are called after loading from the datastore.

I came across this when I implemented an aspect that pointcut all of the
setters.  The setters related to reference or collection descriptors were
sometimes called after the PersistenceBrokerAware methods.

 - Cory

-----Original Message-----
From:   news [mailto:[EMAIL PROTECTED]  On Behalf Of Ravi
Sent:   Friday, 19 August 2005 3:35 AM
To:     ojb-user@db.apache.org
Subject:        Re: afterLookUp() gets called before initialisation of other
objects.


Armin Waibel <arminw <at> apache.org> writes:

> 
> Hi Ravi,
> 
> I can't find significant changes between 0.98 and 1.0.x. The main change
> is, that the target object of the AfterLookupEvent Object was
> immediately nullified after fire the event (because for better
> performance OJB reuse the AfterLookupEvent Object and therefore the 
> target object of the event will be nullified after the "fireEvent" 
> method return).
> 
> class RsIterator:
> // materialize object
> ...
> // lookup reused event object and set current object as target
> getAfterLookupEvent().setTarget(obj);
> // fire event
> getBroker().fireBrokerEvent(getAfterLookupEvent());
> // nullify the target object to prepare event instance for reuse
> getAfterLookupEvent().setTarget(null);
> ...
> 
> Thus, if you queue the AfterLookupEvent objects you will run into 
> problems, e.g. NPE when try to use the target object. In this case you 
> should store the target object in a separate "queue object" when the 
> event is fired.


Hi Armin

Thanks for your response.

I am having problem only with batch load. To make it simple, I created two 
classes TestA and TestB with TestA having reference to TestB and printing 
TestB's name in afterLookUp(). 

If I load TestA objects individually by Id using a criteria like below, it 
works fine and prints TestB's name correctly.

Criteria criteria = new Criteria();
criteria.addEqualTo( "id", id );
QueryByCriteria qByCriteria = new QueryByCriteria( TestA.class, criteria );
return broker.getObjectByQuery( qByCriteria ) );


If I do batch load by an empty Criteria like below, I get
NullPointerException 
in afterLookUp() as TestB is null.

Criteria criteria = new Criteria();
QueryByCriteria qByCriteria = new QueryByCriteria( TestA.class, criteria );
return broker.getCollectionByQuery( qByCriteria );

Following are the classes and mappings.

public class TestA  extends OJBDomainImpl implements PersistenceBrokerAware
{

    private TestB testB;
    private Integer testBId;

    public TestB getTestB()
    {
        return testB;
    }

    public void setTestB(TestB testB)
    {
        this.testB = testB;
    }

    /**
     * this method is called as the first operation before perform an
     * object update.
     */
    public void beforeUpdate(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the last operation within an update
     * operation.
     */
    public void afterUpdate(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the first operation before perform an
     * object insert.
     */
    public void beforeInsert(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the last operation within an insert
     * operation.
     */
    public void afterInsert(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the first operation within a call to
     * PersistenceBroker.delete(...).
     */
    public void beforeDelete(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the last operation within a call to
     * PersistenceBroker.delete(...).
     */
    public void afterDelete(PersistenceBroker broker) throws 
PersistenceBrokerException {

    }

    /**
     * this method is called as the last operation within a call to
     * PersistenceBroker.getObjectByXXX() or
     * PersistenceBroker.getCollectionByXXX().
     */
    public void afterLookup(PersistenceBroker broker) throws 
PersistenceBrokerException
    {
        System.out.println(" Retrieved Test B's name :  "+ testB.getName());
    }
}

public class TestB  extends OJBDomainImpl
{
    private String name;

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }
}

<class-descriptor class="com.wbbs.model.TestA" table="TEST_A">
    <field-descriptor
        name="id"
        column="ID"
        jdbc-type="INTEGER"
        primarykey="true"
        autoincrement="true"
        />
    <field-descriptor
        name="testBId"
        column="TESTB_ID"
        jdbc-type="INTEGER"
        />
    <reference-descriptor
        name="testB"
        class-ref="com.wbbs.model.TestB"
        auto-retrieve="true"
        auto-update="true"
        auto-delete="false"
        >
    <foreignkey field-ref="testBId"/>
     </reference-descriptor>
</class-descriptor>

<class-descriptor class="com.wbbs.model.TestB" table="TEST_B">
    <field-descriptor
        name="id"
        column="ID"
        jdbc-type="INTEGER"
        primarykey="true"
        autoincrement="true"
        />
    <field-descriptor
        name="name"
        column="NAME"
        jdbc-type="VARCHAR"
        />
</class-descriptor>


Same testes work fine with OJB o.98.

Please help..

Regards

Ravi



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