Servlets and Workspaces (AND ClassCastExceptions)

Answer 1

          I have a similiar situation but am not getting a ClassCastException but rather a
          NullPointerException when I try
          to use a contained object in my stored object.
          I do this in the server:
          WorkspaceServicesDef workspaceServices = services.workspace();
          WorkspaceDef defaultWS = workspaceServices.getWorkspace();
          WorkspaceDef dataWS = defaultWS.getWorkspace("DATA_WORKSPACE",
          WorkspaceDef.CREATE,
          WorkspaceDef.SCOPE_SERVER);
          dataWS.store(cMSKey, ms);
          and this in the JSP page:
          // Get the default T3Client Workspace
          WorkspaceDef defaultWS = t3.services.workspace().getWorkspace();
          // Attach to the system subWorkspace already created
          WorkspaceDef myDataWS = defaultWS.getWorkspace("DATA_WORKSPACE",
          WorkspaceDef.ATTACH,
          WorkspaceDef.SCOPE_SERVER);
          MimicServer ms = (MimicServer) myDataWS.fetch("MimicServer");
          Questions:
          1)Must I make the Object I want to store in the WorkSpace Serializable?? The
          Documentation says it can just be
          a Java Object??
          2) In my JSP page I get a good Object reference, but its contents are null
          (Probably because I didn't implement write() and read()).
          Thanks,
          matt obrien
          [email protected]
          Mark Griffith wrote:
          > Alexandre:
          >
          > Although byte for byte the FooObject is the same, according to the VM they
          > are different class. This is because a class's type distinctiveness is
          > based not only its interfaces,methods,data members etc but ALSO on its
          > classloader. There is a different classloader for the
          > serversclasses_FooObject and the servletclasses_FooObject so they are
          > considered different, so you get a CCE.
          >
          > Problem is that the servletclasses directory is designed to solve the
          > problem of reloading servlet classes and objects they used when modified
          > without having to restart the server. But this introduces the problem
          > discussed above. The only solution currently is to put the FooObject only in
          > one place or another. Unfortunately if you want a class in servletclasses
          > to interact classes loaded by the system/server classloader you cannot put
          > the class in the servletclasses without getting a CCE on reload of the
          > servlet in servletclasses. In this case you must put the class only in the
          > serverclasses directory. And this means of course you can only reload the
          > FooObject in the serverclasses directory if you bounce the server. (the
          > default java classloading behavior).
          >
          > This will be handled more elegantly in our next major release Spring 2000,
          > however note (and prepare by designing accordingly) the solution is to allow
          > the Servlet to interact with interfaces not actual classes and these
          > interfaces can be stuffed into system/server loaded classes such as
          > workspaces and httpsessions, thus preventing CCE's.
          >
          > Cheers
          > Mark G
          >
          > Alexandre Aubry wrote:
          >
          > > I have a named workspace which is created at startup of the server
          > > within a starup class.
          > > When the startup method is called, I instantiate and put an object
          > > called FooObject in the workspace.
          > >
          > > Then, in a servlet, called Dispatcher, in the service method, I
          > > retrieved my named workspace and the object
          > > FooObject which is in this workspace. At this time, I have a
          > > ClassCastException.
          > >
          > > To give you more details about my configuration, here is my directory
          > > configuration:
          > > weblogic
          > > |----------- serverclasses
          > > |------------- startupObject
          > > |------------- FooObject
          > > |----------- servletclasses
          > > |------------- myServlet
          > > |------------- FooObject (which is exactly
          > > the same of the serverclasses one)
          > >
          > > Do you have any ideas ? The idea is to instantiate a given object at the
          > > startup of the web server and to retrieve
          > > these objects within servlets and JSPs.
          > >
          > > Regards.
          > >
          > > --
          > > Alexandre Aubry
          > > Consultant
          > > Fi System, The Web Agency
          > > http://www.fisystem.fr
          > > mailto:[email protected]
          > > Phone: [phone] Fax: [phone]
          >
          > --
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