Be paranoid. Set hibernate.show_sql=true. Grab the SQL statement, and execute it manually.
Also, can you change Listing to be non-abstract - even if you never use it? > -----Original Message----- > From: Chris Lewis [mailto:[EMAIL PROTECTED] > Sent: Thursday, July 24, 2008 15:41 > To: Tapestry users > Subject: Re: T5.0.14-SNAPSHOT: strange behavior Dispatcher when using a > Session > > I haven't looked at the source of hibernate (or read) to see what > exactly goes on, but the erratic behavior of load() is precisely the > same as this: > > Listing listing = (Listing)session.createQuery("from Listing > where id=:id") > .setLong("id", Long.parseLong(sListingId)).uniqueResult(); > > I just replaced the load() call with this, so now the source is: > > public class BinaryFileDispatcher implements Dispatcher { > > private Session session; > > public BinaryFileDispatcher(Session session) { > this.session = session; > } > > public boolean dispatch(Request request, Response response) > throws IOException { > > String sListingId = request.getParameter("limg"); > if(sListingId== null) > return false; > > System.out.println("BinaryFileDispatcher.dispatch() -- " + > sListingId); > > Listing listing = (Listing)session.createQuery("from Listing > where id=:id") > .setLong("id", Long.parseLong(sListingId)).uniqueResult(); > > response.setHeader("Content-Type", "text/html"); > > String test = "<html><body><h1>" + listing.getTitle() + > "</h1></body></html>"; > response.setContentLength(test.length()); > PrintWriter writer = response.getPrintWriter("text/html"); > writer.append(test).flush(); > return true; > } > > } > > > Quick summary of the behavior with the following urls: > > 1) request /LStAug/?limg=1 > works > > 2) request /LStAug/?limg=1 (again) > works > > 3) request /LStAug/?limg=2 > breaks > > 4) request /LStAug/?limg=1 > breaks, where it worked before > > (restart container) > > 1) request /LStAug/?limg=2 > works > > 2) request /LStAug/?limg=1 > breaks > > 3) request /LStAug/?limg=2 > breaks > > so strange. > > > Jonathan Barker wrote: > > I'm not sure why it WORKED. > > > > Session.load will try to create an instance of Listing, which it can't > > because it is abstract. > > > > On the other hand, if you do a query, then even though you ask for a > > Listing, Hibernate will look for any descendant of Listing. > > > > The actual object type returned will depend on the actual type for any > > instance found. You can then cast to Listing without a problem. > > > > Get rid of load(). > > > > Jonathan > > > > > >> -----Original Message----- > >> From: Chris Lewis [mailto:[EMAIL PROTECTED] > >> Sent: Thursday, July 24, 2008 14:37 > >> To: Tapestry users > >> Subject: Re: T5.0.14-SNAPSHOT: strange behavior Dispatcher when using a > >> Session > >> > >> Hi Jonathan, > >> > >> Here is my dispatcher. As you can see it's in a very early stage so > it's > >> both small and messy. The query is being done via: > >> session.load(Listing.class, Long.parseLong(sListingId)); > >> > >> It was being done via createQuery and uniqueResult, with the same > results. > >> > >> public class BinaryFileDispatcher implements Dispatcher { > >> > >> private Session session; > >> > >> public BinaryFileDispatcher(Session session) { > >> this.session = session; > >> } > >> > >> public boolean dispatch(Request request, Response response) > >> throws IOException { > >> > >> String sListingId = request.getParameter("limg"); > >> if(sListingId== null) > >> return false; > >> > >> System.out.println("BinaryFileDispatcher.dispatch() -- > " > >> + sListingId); > >> Listing listing = (Listing)session.load(Listing.class, > >> Long.parseLong(sListingId)); > >> > >> response.setHeader("Content-Type", "text/html"); > >> > >> String test = "<html><body><h1>" + listing.getTitle() + > >> "</h1></body></html>"; > >> response.setContentLength(test.length()); > >> > response.getPrintWriter("text/html").append(test).flush(); > >> return true; > >> } > >> > >> } > >> > >> > >> Jonathan Barker wrote: > >> > >>> Post your query and load code. > >>> > >>> > >>> > >>>> -----Original Message----- > >>>> From: Chris Lewis [mailto:[EMAIL PROTECTED] > >>>> Sent: Thursday, July 24, 2008 13:16 > >>>> To: Tapestry users > >>>> Subject: Re: T5.0.14-SNAPSHOT: strange behavior Dispatcher when using > a > >>>> Session > >>>> > >>>> It can't be a data issue. The records are persisted via hibernate and > >>>> work consistently as expected in pages. Like I said, I query the same > >>>> table to which the abstract class is mapped in my index page with no > >>>> problem at all. I also said that it works in the dispatcher for the > >>>> first entity I query, but any subsequent query to a _different_ > entity > >>>> throws that exception. The query is also just a read (select). Any > >>>> > >> other > >> > >>>> ideas? > >>>> > >>>> thanks > >>>> > >>>> Yunhua Sang wrote: > >>>> > >>>> > >>>>> It sounds more like a data issue, check your data in database > >>>>> > >> carefully. > >> > >>>>> Yunhua > >>>>> > >>>>> On Wed, Jul 23, 2008 at 11:18 PM, Chris Lewis > >>>>> > >>>>> > >>>> <[EMAIL PROTECTED]> wrote: > >>>> > >>>> > >>>>>> Hello, > >>>>>> > >>>>>> I have a dispatcher that uses a hibernate session. The dispatcher > is > >>>>>> auto bound and receives the session in the constructor. I'm using > >>>>>> tapestry-hibernate so that session instance is a proxy that gets > the > >>>>>> real session for the current thread (right?). Now in testing my > >>>>>> dispatcher, I give it a url like: > >>>>>> > >>>>>> /MyContext/?limg=2 > >>>>>> > >>>>>> The dispatcher looks for "limg" and if found, queries the session > >>>>>> assuming that its value is the PK of a mapped entity. When I > trigger > >>>>>> > >>>>>> > >>>> the > >>>> > >>>> > >>>>>> dispatcher for the first time it works fine. If I refresh the page, > >>>>>> fine. If I change the value to something else, say 3, then it > breaks > >>>>>> with a org.hibernate.InstantiationException: > >>>>>> > >>>>>> Cannot instantiate abstract class or interface: > >>>>>> > >>>>>> > >>>> com.mypackage.data.Listing > >>>> > >>>> > >>>>>> If I change the value back to 2, the same thing happens! "Listing" > is > >>>>>> > >>>>>> > >>>> an > >>>> > >>>> > >>>>>> abstract class mapped as a super class entity via: > >>>>>> > >>>>>> @Entity > >>>>>> @Inheritance(strategy = InheritanceType.JOINED) > >>>>>> > >>>>>> Any clue what's going on here? Two things are perplexing me: > >>>>>> > >>>>>> 1) Querying mapped super classes is legal, and I in fact the same > >>>>>> > >> thing > >> > >>>>>> on my Index page with no problem. > >>>>>> 2) The query works the first time, but as soon as the id changes it > >>>>>> > >> is > >> > >>>>>> forever broken until I restart the container. > >>>>>> > >>>>>> Thanks in advance! > >>>>>> > >>>>>> chris > >>>>>> > >>>>>> -- > >>>>>> http://thegodcode.net > >>>>>> > >>>>>> > >>>>>> ------------------------------------------------------------------- > -- > >>>>>> To unsubscribe, e-mail: [EMAIL PROTECTED] > >>>>>> For additional commands, e-mail: [EMAIL PROTECTED] > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>> -------------------------------------------------------------------- > - > >>>>> To unsubscribe, e-mail: [EMAIL PROTECTED] > >>>>> For additional commands, e-mail: [EMAIL PROTECTED] > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> > >>>> -- > >>>> http://thegodcode.net > >>>> > >>>> > >>> > >>> --------------------------------------------------------------------- > >>> To unsubscribe, e-mail: [EMAIL PROTECTED] > >>> For additional commands, e-mail: [EMAIL PROTECTED] > >>> > >>> > >>> > >>> > >> -- > >> http://thegodcode.net > >> > > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > -- > http://thegodcode.net --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
