Hi Howard,
Thanks for the answer.
What is the best generic solution?
1. I implemented a Tapestry extension named CayenneValuePersister
subclass of DefaultValuePersister and DataObjectCopier subclass of
SerializableCopier. Former register DataObjectCopier as value copier,
DataObjectCopier assigns the DataContext from the Visit object to the
DataObject after deserialize.
Or
2. Just to implement Inmutable to the DataObjects.
Are messages sent to the Tapestry Developer censored?
Regards
David
> -----Original Message-----
> From: Howard M. Lewis Ship [mailto:hlshi..ttbi.com]
> Sent: Wednesday, February 19, 2003 5:13 PM
> To: andru..bjectstyle.org
> Cc: Tapestry Users
> Subject: RE: Hollow state
>
>
> Page persistence has changed significantly in 2.4.
>
> Tapestry is now very careful to make copies of persistent
> values. A copy is made from fireObservedChange() and stored
> into the HttpSession. A copy of the copy is made and use to
> update page properties in later request cycles.
>
> This is good and bad.
>
> Good: Much better assurance than an application that works
> in a single JVM will work in a cluster. Changing a
> collection (Map, List) after
> fireObservedChange() will not affect the persistent state of
> the property.
>
> Bad: Painful when you get beyond simple immutable objects.
> Deep copy problems (Tapestry only does a shallow copy of Maps
> and Lists). May have to serialize/deserialize to make a copy
> of an unknown object.
>
> You can create new adaptors easily enough; you can also
> identify an object as "immutable" (either by having it
> implement IImmutable or by createing an immutable adaptor for
> the class); immutable objects are simple retained, not copied.
>
> Still working the kinks out, which is why 2.4 is still alpha!
>
> --
> Howard M. Lewis Ship
> Creator, Tapestry: Java Web Components
> http://jakarta.apache.org/proposals/tapestry
>
>
>
> > -----Original Message-----
> > From: Andrus Adamchik [mailto:andru..bjectstyle.org]
> > Sent: Wednesday, February 19, 2003 1:08 PM
> > To: dsoli..egosoft.com.mx
> > Cc: cayenne-use..bjectstyle.org
> > Subject: Re: Hollow state
> >
> >
> > Hmm.. the code in question in CayenneDataObject is:
> >
> > if (persistenceState == PersistenceState.HOLLOW) {
> > dataContext.refetchObject(objectId);
> > }
> >
> > The failure means that object is both HOLLOW and has no
> > associated DataContext. Normally only TRANSIENT objects have
> > null DataContext. I suspect the root cause of this is
> > deserialization in Tapestry. The fact that it works on 2.3,
> > but not 2.4 also points to that.
> >
> > I haven't looked at Tapestry 2.4 yet, is there changes in how
> > serialization works between pages?
> >
> > Andrus
> >
> >
> >
> > > I'm developing an application with Cayenne 1.0a5 and Tapestry 2.4
> > > alpha 3. I'm getting exceptions like this:
> > >
> > > java.lang.NullPointerException
> > > *
> > >
> >
> org.objectstyle.cayenne.CayenneDataObject.readProperty(CayenneDataObje
> > > ct
> > > .java:183)
> > >
> > > *
> > >
> >
> com.ixe.isis.ixenetadmin.model._CustomerService.getService(_CustomerSe
> > > rv
> > > ice.java:134)
> > >
> > > *
> > >
> >
> com.ixe.isis.ixenetadmin.model.CustomerService.getDescription(Customer
> > > Se
> > > rvice.java:18)
> > >
> > > *
> > >
> >
> com.ixe.isis.ixenetadmin.pages.customer.ServiceSignatureGroups.getTitl
> > > e(
> > > ServiceSignatureGroups.java:64)
> > >
> > > * java.lang.reflect.Method.invoke(Native Method)
> > >
> > > * ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java)
> > >
> > > * ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java)
> > >
> > > *
> > >
> >
> ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor
> > > .j
> > > ava)
> > >
> > > *
> > >
> ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java)
> > >
> > > * ognl.OgnlRuntime.getProperty(OgnlRuntime.java)
> > >
> > > * ognl.ASTProperty.getValueBody(ASTProperty.java)
> > >
> > > * ognl.SimpleNode.getValue(SimpleNode.java)
> > >
> > > * ognl.Ognl.getValue(Ognl.java)
> > >
> > > * ognl.Ognl.getValue(Ognl.java)
> > >
> > > *
> > >
> >
> net.sf.tapestry.binding.ExpressionBinding.resolveProperty(ExpressionBi
> > > nd
> > > ing.java:232)
> > >
> > > *
> > >
> >
> net.sf.tapestry.binding.ExpressionBinding.getObject(ExpressionBinding.
> > > ja
> > > va:225)
> > >
> > > *
> > >
> >
> net.sf.tapestry.binding.AbstractBinding.getString(AbstractBinding.java
> > > :1
> > > 41)
> > >
> > > The real problem is some cayenne EOs are in hollow state
> > and refetch
> > > is not automatic.
> > >
> > > ixenetadmin/ServiceSignatureGroups/customer {[]<oid:
> > > com.ixe.isis.ixenetadmin.model.Customer: <RIM_NO: 34177>; state:
> > > hollow>}
> > > ixenetadmin/ServiceSignatureGroups/service {[]<oid:
> > > com.ixe.isis.ixenetadmin.model.CustomerService:
> > <ID_CLIENTE_SERVICIO:
> > > 4e5817c2-c0a8-141e-0069-cc0e0373ff20>; state: hollow>}
> > >
> > > I can "patch" the code to refetch every EO in hollow state, but is
> > > this the "normal" behavior?
> > >
> > > Note: these objects are persistant properties to the page.
> > >
> > > I developed a prototype using Tapestry 2.3 and didn't experience
> > > something similar.
> > >
> > > Any ideas?
> > >
> > > Regards
> > >
> > > David
> > >
> > >
> >
> >
> >
>
>
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