[Building Sakai] ClassCastException implementing CourseGradesToSpreadsheetConverter

[Bryan Holladay]

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/calendar/"
+ 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.CourseGradesToSpreadsheetConverterSample
>>>"
>>> 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-grad
>>>e
>>>book-tool].[sakai.gradebook.tool]:691 - Servlet.service() for servlet
>>>sakai.gradebook.tool threw exception
>>>java.lang.ClassCastException:
>>>org.sakaiproject.gradebooksample.CourseGradesToSpreadsheetConverterSample
>>>cannot be cast to
>>>org.sakaiproject.tool.gradebook.CourseGradesToSpreadsheetConverter
>>>        at
>>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.getSpreadsheetDa
>>>t
>>>a(CourseGradeDetailsBean.java:322)
>>>        at
>>>org.sakaiproject.tool.gradebook.ui.CourseGradeDetailsBean.exportCsv(Course
>>>G
>>>radeDetailsBean.java:296)
>>>...
>>>
>>>
>>>--
>>>
>>>Christopher Gross
>>>University of Florida
>>>
>>>_______________________________________________
>>>sakai-dev mailing list
>>>sakai-dev at collab.sakaiproject.org
>>>http://collab.sakaiproject.org/mailman/listinfo/sakai-dev
>>>
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>>
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