in fact this is way better because the lock granularity is flexible and
in the hands of the target implementation!
in the bookmarkable page case, the bookmarkable page is locked, but not
when it's a redirect:
/**
* @see wicket.IRequestTarget#getLock(RequestCycle)
*/
public Object getLock(RequestCycle requestCycle)
{
// we need to lock when we are not redirecting, i.e. we are
// actually rendering the page
return !requestCycle.getRedirect() ? requestCycle.getSession() :
null;
}
one can imagine other locking techniques as the result of getLock()
implementations...
Jonathan Locke wrote:
no, no, you're right. that call to get the request target from the
request cycle should just be above the factory call and the lock
should work.
sorry, i was jumping to conclusions...
Igor Vaynberg wrote:
currently we lock the processing on the target.getLock()....why not
lock the page instantiation on the same lock?
-Igor
On 1/5/06, *Jonathan Locke * <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
also, because we have Session.get(), any non-locked object (image
object, for example)
that accesses the session this way could have threading
problems. but
that doesn't
seem very likely.
Jonathan Locke wrote:
>
> just realized that the target lock problem will get much worse
if igor
> ever gets his way with delayed init. then components could
naively
> do something involving the parent that wound up accessing the
session.
>
> Jonathan Locke wrote:
>>
>> i think you should be synchronizing on the target's lock,
retrieved
>> by target.getLock()
>>
>> Martijn Dashorst wrote:
>>> Here's my patch for this code. I think this should work but
I'd like
>>> others to take a look at it:
>>>
>>> I changed the page construction, such that it is done within a
>>> synchronized block which synchronizes on the session object.
>>>
>>> In class:
wicket.request.compound.DefaultRequestTargetResolverStrategy
>>>
>>> protected IRequestTarget
resolveBookmarkablePage(RequestCycle
>>> requestCycle,
>>> RequestParameters requestParameters)
>>> {
>>> String bookmarkablePageClass =
>>> requestParameters.getBookmarkablePageClass();
>>> Session session = requestCycle.getSession();
>>> Application application = session.getApplication();
>>> Class pageClass;
>>> try
>>> {
>>> pageClass =
>>> session.getClassResolver().resolveClass(bookmarkablePageClass);
>>> }
>>> catch (RuntimeException e)
>>> {
>>> return new
>>> WebErrorCodeResponseTarget(HttpServletResponse.SC_NOT_FOUND,
>>> "Unable to load Bookmarkable Page");
>>> }
>>>
>>> try
>>> {
>>> final IPageFactory pageFactory =
session.getPageFactory();
>>> synchronized (session) {
>>> Page newPage = pageFactory.newPage(pageClass,
>>> new
>>> PageParameters(requestParameters.getParameters()));
>>> // the response might have been set in the
>>> constructor of
>>> // the bookmarkable page
>>> IRequestTarget requestTarget =
>>> requestCycle.getRequestTarget();
>>> // is it possible that there is already
another
>>> request target at
>>> // this point then the 2 below?
>>> if (!(requestTarget instanceof
IPageRequestTarget ||
>>> requestTarget instanceof IBookmarkablePageRequestTarget))
>>> {
>>> requestTarget = new
PageRequestTarget(newPage);
>>> }
>>> return requestTarget;
>>> }
>>> }
>>> catch (RuntimeException e)
>>> {
>>> throw new WicketRuntimeException("Unable to
instantiate
>>> Page class: "
>>> + bookmarkablePageClass + ". See below for
>>> details.", e);
>>> }
>>> }
>>>
>>>
>>> On 1/5/06, *Martijn Dashorst* < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
>>> <mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>> wrote:
>>>
>>> Testcase:
>>>
>>> Take wicket examples, linkomatic.
>>>
>>> Put a breakpoint on the Page3 constructor. Click on the
pagelink
>>> to the Page3 page twice (on the same page) and see two
threads
>>> waiting.
>>>
>>> The synchronized block seems to be too late.
>>>
>>> Martijn
>>>
>>>
>>>
>>> On 1/5/06, *Martijn Dashorst* < [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
>>> <mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>> wrote:
>>>
>>> According to our limited test, BookmarkablePageTargets
are
>>> executed outside the synchronized block. This means
that any
>>> session access in the constructor of the Page is not
>>> synchronized, and will get you into trouble. This is
what
>>> happens in our application.
>>>
>>> Questions:
>>> - is this by design?
>>> - has anyone changed this behavior since december 16?
>>>
>>> Martijn
>>>
>>> -- Living a wicket life...
>>>
>>> Martijn Dashorst - http://www.jroller.com/page/dashorst
>>> <http://www.jroller.com/page/dashorst>
>>>
>>> Wicket 1.1 is out:
http://wicket.sourceforge.net/wicket-1.1
>>>
>>>
>>>
>>> -- Living a wicket life...
>>>
>>> Martijn Dashorst - http://www.jroller.com/page/dashorst
>>>
>>> Wicket 1.1 is out: http://wicket.sourceforge.net/wicket-1.1
>>>
>>>
>>>
>>>
>>> --
>>> Living a wicket life...
>>>
>>> Martijn Dashorst - http://www.jroller.com/page/dashorst
<http://www.jroller.com/page/dashorst>
>>>
>>> Wicket 1.1 is out: http://wicket.sourceforge.net/wicket-1.1
>>
>>
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