Re: various exceptions with cayenne 1.2RC2

Wed, 28 Jun 2006 07:14:39 -0700

I see. In 1.2 Cayenne supports field-based persistence (albeit only on the remote client at the moment). As we move forward, this may become the default way to store properties (especially in light of JPA spec compliance). So the runtime has to work with both DataObject and POJO classes. The problem seems to be in the attempt to combine both approaches for the same entity class. Probably we shouldn't be mixing them when compiling ClassDescriptors.
I'd appreciate a bug report - with a reproducible test case, I'll take another look at how the ClassDescriptors are implemented. 

Andrus


On Jun 28, 2006, at 2:07 PM, Robert Zeigler wrote:


Found the issue.
AssignmentTransaction has a one-to-many relationship named
"studentResponses". It also had a private variable:
private List studentResponses. In certain situations (described
momentarily), it appears that the field accessor class is "seeing" the

private variable instead of the relationship. When I changed the  
name of

the private variable, the problem disappeared. I was also able to
duplicate the issue in an entirely unrelated (and much simpler) data

map. This seems like a bug to me; seems like FieldAccessor  
shouldn't be

able to grab/use my private variables. :) If you want, I can open up a
jira issue and attach a really simple map and bit of code that will
illustrate the issue.

In any event, here is the situation where the invalid access occurs:

X has a to-many relationship to Y. Z also has a to-many  
relationship to Y.

Y has a to-many relationship named k, and also has a private List k;
declaration.
xinstance, zinstance , and yinstance are instances of X, Z and Y,
respectively, and  xinstance and zinstance share a yinstance.
X loads its list of Y via xinstance.getY(). xinstance does some
processing that results in
k's initialization in the shared yinstance.  zinstance now does
zinstance.getY() and attempts to perform some operation on the list
(size(), get(0), iterator(), etc... something that forces cayenne to
fault the toManyList). While processing the shared yinstance, cayenne
will choke with a ClassCastException because it will see the private
variable k (now initialized, eg, to an ArrayList) rather than the
relationship with the same name.


Apologies if the explanation is a bit opaque... again... I'll work  
up a

trivial data map + code example that triggers the error.

Robert

Robert Zeigler wrote:

Didn't get back to this last night, sorry. Ok, I sat down and wrote a
quick test to call the same code, external of tapestry.
The code outside of tapestry didn't result in a class cast exception.
Instead, it resulted in an ExpressionException (unable to evaluate

assignment.name).  Turns out that the assignment object doesn't  
have a

"name" property (it's "title"). The thing that seems odd here is that
the code throws no exceptions with M5 (I suspect this has to do with
removing BeanUtils as a dependency?).

Anyway... the lack of a ClassCastException says that something weird

must be happening in tapestry or my code somewhere. I'll keep  
looking.

I don't define collection setters in the DO; neither my code nor

tapestry should be initializing the relationship, but I'll keep  
digging

to see what I can find.

Robert


Andrus Adamchik wrote:


In poking around, I saw a place where if something was

transient, an ArrayList was returned... but I can't find it  
again at the
moment; I'll look later tonight when I have a bit of time and  
see if I

can find it again.


Let us know if you find those - this shouldn't happen in  
DataObjects.

The code below looks clean, so the cause is somewhere else. Is it
possible that Tapestry or the user code initializes the relationship
list on its own? Do you define collection setters in your DO's
(Cayenne does not by default)?

Andrus



On Jun 27, 2006, at 2:54 AM, Robert Zeigler wrote:



Hi all,


Way back when 1.2B1 was released, I reported a weird fault  
resolving
exception. I didn't have time then to look into it further. I  
just tried
out cayenne 1.2RC2 and am still seeing the same weird behavior  
(maybe

I'm doing something weird. ;). I do have time now to look into it

further, but am getting stuck before I can get started by a  
separate

issue.

My code:
    public List getTransactionsForCourse(Course course) {
        List ret = this.getAssignmentTransactions();
        ret =

ExpressionFactory.matchExp 
("assignment.course.name",course.getName()).filterObjects(ret);


        List orderings = new ArrayList();
        orderings.add(new Ordering("assignment.name",true));
        orderings.add(new Ordering("scoreAsFloat",false));
        Ordering.orderList(ret,orderings);
        return ret;
    }

assignmentTransactions is a one to many relationship.

Calling said code is resulting in the following exception:

    *

org.objectstyle.cayenne.property.AbstractCollectionProperty.ensureC 
ollectionValueHolderSet(AbstractCollectionProperty.java:159)



    *

org.objectstyle.cayenne.property.AbstractCollectionProperty.injectV 
alueHolder(AbstractCollectionProperty.java:142)



    *

org.objectstyle.cayenne.property.BaseClassDescriptor.injectValueHol 
ders(BaseClassDescriptor.java:218)



    *

org.objectstyle.cayenne.access.DataContext.localObject 
(DataContext.java:1924)



    *

org.objectstyle.cayenne.access.ObjectResolver.objectFromDataRow 
(ObjectResolver.java:237)



    *

org.objectstyle.cayenne.access.ObjectResolver.objectsFromDataRows 
(ObjectResolver.java:155)



    *

org.objectstyle.cayenne.access.ObjectResolver.synchronizedObjectsFr 
omDataRows(ObjectResolver.java:134)



    *

org.objectstyle.cayenne.access.DataDomainQueryAction.interceptObjec 
tConversion(DataDomainQueryAction.java:373)



    *

org.objectstyle.cayenne.access.DataDomainQueryAction.execute 
(DataDomainQueryAction.java:151)



    *

org.objectstyle.cayenne.access.DataDomain.onQuery 
(DataDomain.java:766)


    *

org.objectstyle.cayenne.util.ObjectContextQueryAction.runQuery 
(ObjectContextQueryAction.java:253)



    *

org.objectstyle.cayenne.access.DataContextQueryAction.execute 
(DataContextQueryAction.java:90)



    *

org.objectstyle.cayenne.access.DataContext.onQuery 
(DataContext.java:1422)



    *

org.objectstyle.cayenne.access.DataContext.performQuery 
(DataContext.java:1411)



    *

org.objectstyle.cayenne.access.ToManyList.resolvedObjectList 
(ToManyList.java:343)



    *
org.objectstyle.cayenne.access.ToManyList.size(ToManyList.java:296)
    *

org.objectstyle.cayenne.exp.Expression.filterObjects 
(Expression.java:458)



    * org.eledge.domain.User.getTransactionsForCourse(User.java:92)

    * org.eledge.domain.User.getGradebookGradedResponses 
(User.java:197)

    *

org.eledge.domain.User.getGradedGradebookGradedResponses 
(User.java:192)


    *

org.eledge.domain.User.getHasGradedGradebookGradedResponses 
(User.java:188)



    * sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    *

sun.reflect.NativeMethodAccessorImpl.invoke 
(NativeMethodAccessorImpl.java:39)



    *

sun.reflect.DelegatingMethodAccessorImpl.invoke 
(DelegatingMethodAccessorImpl.java:25)



    * java.lang.reflect.Method.invoke(Method.java:585)
    * ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:491)
    * ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:785)

    * ognl.ObjectMethodAccessor.callMethod 
(ObjectMethodAccessor.java:61)

    * ognl.OgnlRuntime.callMethod(OgnlRuntime.java:819)
    * ognl.ASTMethod.getValueBody(ASTMethod.java:75)
    * ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    * ognl.SimpleNode.getValue(SimpleNode.java:210)
    * ognl.ASTChain.getValueBody(ASTChain.java:109)
    * ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
    * ognl.SimpleNode.getValue(SimpleNode.java:210)
    * ognl.Ognl.getValue(Ognl.java:333)
    * ognl.Ognl.getValue(Ognl.java:310)
    *

org.apache.tapestry.binding.ExpressionBinding.resolveProperty 
(ExpressionBinding.java:201)



    *

org.apache.tapestry.binding.ExpressionBinding.getObject 
(ExpressionBinding.java:194)



    *

org.apache.tapestry.binding.AbstractBinding.getBoolean 
(AbstractBinding.java:77)



    *

org.apache.tapestry.param.BooleanParameterConnector.setParameter 
(BooleanParameterConnector.java:51)



    *

org.apache.tapestry.param.ParameterManager.setParameters 
(ParameterManager.java:105)



    *

org.apache.tapestry.AbstractComponent.prepareForRender 
(AbstractComponent.java:898)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:853)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)



    *

org.apache.tapestry.components.RenderBody.renderComponent 
(RenderBody.java:45)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)



    *

org.apache.tapestry.components.RenderBody.renderComponent 
(RenderBody.java:45)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)



    * org.apache.tapestry.html.Body.renderComponent(Body.java:269)
    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)



    *

org.apache.tapestry.components.RenderBody.renderComponent 
(RenderBody.java:45)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)




    * org.apache.tapestry.html.Shell.renderComponent(Shell.java: 
124)

    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.BaseComponent.renderComponent 
(BaseComponent.java:118)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.BaseComponent.renderComponent 
(BaseComponent.java:118)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.AbstractComponent.renderBody 
(AbstractComponent.java:624)



    * org.mb.tapestry.base.IfBean.renderComponent(IfBean.java:83)
    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.BaseComponent.renderComponent 
(BaseComponent.java:118)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)


    *

org.apache.tapestry.BaseComponent.renderComponent 
(BaseComponent.java:118)



    *

org.apache.tapestry.AbstractComponent.render 
(AbstractComponent.java:857)



    * org.apache.tapestry.AbstractPage.renderPage 
(AbstractPage.java:300)

    *

org.apache.tapestry.engine.RequestCycle.renderPage 
(RequestCycle.java:368)



    *

org.apache.tapestry.engine.AbstractEngine.renderResponse 
(AbstractEngine.java:749)



    *
org.apache.tapestry.engine.PageService.service(PageService.java:77)
    *

org.apache.tapestry.engine.AbstractEngine.service 
(AbstractEngine.java:889)



    * org.eledge.EledgeEngine.service(EledgeEngine.java:60)
    *

org.apache.tapestry.ApplicationServlet.doService 
(ApplicationServlet.java:198)



    *

org.apache.tapestry.ApplicationServlet.doGet 
(ApplicationServlet.java:159)



    * javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
    * javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
    *

org.mortbay.jetty.servlet.ServletHolder.handle 
(ServletHolder.java:428)


    *

org.mortbay.jetty.servlet.WebApplicationHandler 
$CachedChain.doFilter(WebApplicationHandler.java:830)



    *

org.eledge.OldEledgePagesFilter.doFilter 
(OldEledgePagesFilter.java:64)


    *

org.mortbay.jetty.servlet.WebApplicationHandler 
$CachedChain.doFilter(WebApplicationHandler.java:821)



    *

org.mortbay.jetty.servlet.WebApplicationHandler.dispatch 
(WebApplicationHandler.java:471)



    *

org.mortbay.jetty.servlet.ServletHandler.handle 
(ServletHandler.java:568)


    * org.mortbay.http.HttpContext.handle(HttpContext.java:1530)
    *

org.mortbay.jetty.servlet.WebApplicationContext.handle 
(WebApplicationContext.java:633)



    * org.mortbay.http.HttpContext.handle(HttpContext.java:1482)
    * org.mortbay.http.HttpServer.service(HttpServer.java:909)

    * org.mortbay.http.HttpConnection.service 
(HttpConnection.java:816)

    *
org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:982)

    * org.mortbay.http.HttpConnection.handle(HttpConnection.java: 
833)

    *

org.mortbay.http.SocketListener.handleConnection 
(SocketListener.java:244)




    * org.mortbay.util.ThreadedServer.handle(ThreadedServer.java: 
357)
    * org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java: 
534)




This is a tapestry (3.0.3) webapp, running with the  
JettyLauncher. I've
done a clean recompile, but no good. I dug into the code, and it  
looks
like ensureCollectionValueHolderSet is trying to cast an  
ArrayList as a
ValueHolder.  In poking around, I saw a place where if something  
was
transient, an ArrayList was returned... but I can't find it  
again at the
moment; I'll look later tonight when I have a bit of time and  
see if I

can find it again.  Anyway... thoughts? Cayenne bug? Something I've
screwed up?

Robert
































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