[Building Sakai] ClassCastException implementing CourseGradesToSpreadsheetConverter

Wed Aug 17 12:09:46 PDT 2011

We are already building our own edu-services (1.1.x) because of custom
code we had to put in for the course management service and we have made
sure to remove the edu-services-assembly dependency from the core-deploy
pom.

-Chris

On 8/17/11 2:28 PM, "Bryan Holladay" <holladay at longsight.com> wrote:

>I just ran into this issue again today... I seriously just copied a
>Class Cast line of code from a line above it and it complained...  I
>was able to fix it by building edu-services_trunk in my own tomcat,
>then building gradebook again.  I think it's an issue w/the
>edu-service dependency jar's being compiled w/a different compiler.
>
>-Bryan
>
>On Wed, Aug 17, 2011 at 1:41 PM, Gross,Christopher <ufchrisg at ufl.edu>
>wrote:
>> Your emails gave me one idea, and that was to remove the
>> <scope>provided</scope> from the following dependency in the pom.xml for
>> both converters:
>>
>> <dependency>
>>        <groupId>org.sakaiproject.edu-services.gradebook</groupId>
>>        <artifactId>gradebook-service-hibernate</artifactId>
>>        <scope>provided</scope>
>> </dependency>
>>
>> At the very least it did one thing I was expecting and that was it
>>placed
>> the gradebook-service-hibernate-1.1.2.jar in the WEB-INF/lib for the
>> converters.  Unfortunately, this did not resolve the issue and the
>> exception persists.
>>
>> -Chris
>>
>>
>> On 8/17/11 10:28 AM, "Bryan Holladay" <holladay at longsight.com> wrote:
>>
>>>A recent example I ran into was
>>>https://jira.sakaiproject.org/browse/SAM-1121
>>>
>>>Just adding this one line:
>>>
>>>Calendar calendar =
>>>org.sakaiproject.calendar.cover.CalendarService.getCalendar("/calendar/c
>>>al
>>>endar/"
>>>+ siteId + "/main");
>>>
>>>Threw this exception:
>>>
>>>Bean named 'org.sakaiproject.calendar.api.CalendarService' must be of
>>>type [org.sakaiproject.calendar.api.CalendarService], but was actually
>>>of type [org.sakaiproject.calendar.impl.DbCalendarService]
>>>
>>>
>>>You can look at my patch to get an idea of an approach to take
>>>(hopefully).  It basically comes down to: move it to a different part
>>>of the architecture.
>>>
>>>-Bryan
>>>
>>>
>>>On Wed, Aug 17, 2011 at 10:23 AM, Bryan Holladay
>>><holladay at longsight.com>
>>>wrote:
>>>> This is an issue I see a lot.  It basically comes down to this:
>>>>
>>>> "The class objects were loaded in different classloaders, therefore
>>>> the instances created from in each of classes are seen as
>>>> 'incompatible'. This is a common issue in a an environment where there
>>>> are many different classloaders being used and objects are being
>>>> passed around. These issues can easily arise in JEE and portal
>>>> environments."
>>>>
>>>> -Source: Internet/Google
>>>>
>>>>  just throwing out quick ideas w/o knowing how your code is set up:
>>>>
>>>> Try to implement this in the same layer as the API or don't import
>>>> jars, but instead use what's already there or access it from
>>>> Edu-services if that's where it's create, ect...
>>>>
>>>>
>>>> Thanks,
>>>> Bryan
>>>>
>>>>
>>>>
>>>> On Wed, Aug 17, 2011 at 10:12 AM, Gross,Christopher <ufchrisg at ufl.edu>
>>>>wrote:
>>>>> The jars are there (the converters appear in tomcat/components/).
>>>>> Besides, a missing jar would likely give me some problems when tomcat
>>>>>is
>>>>> starting up and/or result in a bean failing to initialize.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> -Chris
>>>>>
>>>>> On 8/17/11 4:26 AM, "DAVID ROLDAN MARTINEZ" <darolmar at upvnet.upv.es>
>>>>>wrote:
>>>>>
>>>>>>I suggest checking if you have all the *.jar you need available.
>>>>>>
>>>>>>Hope this helps.
>>>>>>
>>>>>>David
>>>>>>________________________________________
>>>>>>De: sakai-dev-bounces at collab.sakaiproject.org
>>>>>>[sakai-dev-bounces at collab.sakaiproject.org] En nombre de
>>>>>>Gross,Christopher [ufchrisg at ufl.edu]
>>>>>>Enviado el: martes, 16 de agosto de 2011 22:54
>>>>>>Para: sakai-dev at collab.sakaiproject.org
>>>>>>Asunto: [Building Sakai] ClassCastException implementing
>>>>>>CourseGradesToSpreadsheetConverter
>>>>>>
>>>>>>Hello!
>>>>>>
>>>>>>We are attempting to create our own implementation of the
>>>>>>CourseGradesToSpreadsheetConverter interface (gradebook service),
>>>>>>however
>>>>>>we are receiving a ClassCastException when attempting to export
>>>>>>course
>>>>>>grades from the gradebook tool. To ensure this was not a problem in
>>>>>>our
>>>>>>code we set gradebook.coursegrades.converter to
>>>>>>"org.sakaiproject.gradebooksample.CourseGradesToSpreadsheetConverterS
>>>>>>am
>>>>>>ple
>>>>>>"
>>>>>> in sakai.properties, which is the sample that is included in the
>>>>>>gradebook tool's source. The result is that both implementations are
>>>>>>causing the same ClassCastException when a user attempts to export
>>>>>>the
>>>>>>course grades in the gradebook.
>>>>>>
>>>>>>This setup is using gradebook 2.8.x and edu-services 1.1.x
>>>>>>
>>>>>>A small snippet of the output is below.
>>>>>>
>>>>>>I am hoping that someone may see something that I am not or will
>>>>>>confirm
>>>>>>that this is something that needs to be submitted to the JIRA.
>>>>>>
>>>>>>Thanks!
>>>>>>
>>>>>>----
>>>>>>
>>>>>>2011-08-16 16:28:05.634 [ERROR]
>>>>>>org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/sakai
>>>>>>-g
>>>>>>rad
>>>>>>e
>>>>>>book-tool].[sakai.gradebook.tool]:691 - Servlet.service() for servlet
>>>>>>sakai.gradebook.tool threw exception
>>>>>>java.lang.ClassCastException:
>>>>>>org.sakaiproject.gradebooksample.CourseGradesToSpreadsheetConverterSa
>>>>>>mp
>>>>>>le
>>>>>>cannot be cast to
>>>>>>org.sakaiproject.tool.gradebook.CourseGradesToSpreadsheetConverter
>>>>>>        at
>>>>>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.getSpreadsh
>>>>>>ee
>>>>>>tDa
>>>>>>t
>>>>>>a(CourseGradeDetailsBean.java:322)
>>>>>>        at
>>>>>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.exportCsv(C
>>>>>>ou
>>>>>>rse
>>>>>>G
>>>>>>radeDetailsBean.java:296)
>>>>>>...
>>>>>>
>>>>>>
>>>>>>--
>>>>>>
>>>>>>Christopher Gross
>>>>>>University of Florida
>>>>>>
>>>>>>_______________________________________________
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>>>>>>
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>>>>>
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>>
>>