well, its either we lock on the page, or you have to make sure all
your code is threadsafe.
yes, this can be a problem for a lot of concurrent ajax requests, you
just have to make sure your responses are fast. eg if you have a
time-consuming operation do it in a background thread and make ajax
calls poll instead of block.
-igor
On Tue, Nov 10, 2009 at 2:09 PM, Pamir Erdem <pamir.er...@gmail.com> wrote:
> Hi
>
> There are parts in web which make ajax calls. In this situtation on request
> blocks the piece of code till it returns a value. Do you recommend anything
> about ajax calls in a web page?
>
> Thanks
> Pamir
> On Tue, Nov 10, 2009 at 9:28 PM, Igor Vaynberg <igor.vaynb...@gmail.com>wrote:
>
>> can you submit a quickstart that reproduces this?
>>
>> the lock on session only blocks concurrent requests from the browser,
>> which is usually not a big deal because most users operate one window
>> at a time.
>>
>> also we do not get the same results in our wicket-threadtest project.
>>
>> -igor
>>
>> On Tue, Nov 10, 2009 at 10:17 AM, Pamir Erdem <pamir.er...@gmail.com>
>> wrote:
>> > From wicket source code WebRequestCycleProcessor has a lock on session.
>> > (Look at the source code below).
>> > From a profiler we can easily observe that %57 of the time is spent on
>> this
>> > function especially on lock region.
>> > Is there any way to speed it up this source code ?
>> >
>> >
>> > /**
>> > * @see
>> >
>> org.apache.wicket.request.IRequestCycleProcessor#resolve(org.apache.wicket.RequestCycle,
>> > * org.apache.wicket.request.RequestParameters)
>> > */
>> > public IRequestTarget resolve(final RequestCycle requestCycle,
>> > final RequestParameters requestParameters)
>> > {
>> > IRequestCodingStrategy requestCodingStrategy =
>> requestCycle.getProcessor()
>> > .getRequestCodingStrategy();
>> >
>> > final String path = requestParameters.getPath();
>> > IRequestTarget target = null;
>> >
>> > // See whether this request points to a bookmarkable page
>> > if (requestParameters.getBookmarkablePageClass() != null)
>> > {
>> > target = resolveBookmarkablePage(requestCycle, requestParameters);
>> > }
>> > // See whether this request points to a rendered page
>> > else if (requestParameters.getComponentPath() != null)
>> > {
>> > // marks whether or not we will be processing this request
>> > boolean processRequest = true;
>> > synchronized (requestCycle.getSession())
>> > {
>> > // we need to check if this request has been flagged as
>> > // process-only-if-path-is-active and if so make sure this
>> > // condition is met
>> > if (requestParameters.isOnlyProcessIfPathActive())
>> > {
>> > // this request has indeed been flagged as
>> > // process-only-if-path-is-active
>> >
>> > Session session = Session.get();
>> > IPageMap pageMap =
>> > session.pageMapForName(requestParameters.getPageMapName(),
>> > false);
>> > if (pageMap == null)
>> > {
>> > // requested pagemap no longer exists - ignore this
>> > // request
>> > processRequest = false;
>> > }
>> > else if (pageMap instanceof AccessStackPageMap)
>> > {
>> > AccessStackPageMap accessStackPageMap = (AccessStackPageMap)pageMap;
>> > if (accessStackPageMap.getAccessStack().size() > 0)
>> > {
>> > final Access access = (Access)accessStackPageMap.getAccessStack()
>> > .peek();
>> >
>> > final int pageId = Integer
>> > .parseInt(Strings.firstPathComponent(requestParameters
>> > .getComponentPath(), Component.PATH_SEPARATOR));
>> >
>> > if (pageId != access.getId())
>> > {
>> > // the page is no longer the active page
>> > // - ignore this request
>> > processRequest = false;
>> > }
>> > else
>> > {
>> > final int version = requestParameters.getVersionNumber();
>> > if (version != Page.LATEST_VERSION &&
>> > version != access.getVersion())
>> > {
>> > // version is no longer the active version -
>> > // ignore this request
>> > processRequest = false;
>> > }
>> > }
>> > }
>> > }
>> > else
>> > {
>> > // TODO also this should work..
>> > }
>> > }
>> > }
>> > if (processRequest)
>> > {
>> > try
>> > {
>> > target = resolveRenderedPage(requestCycle, requestParameters);
>> > }
>> > catch (IgnoreAjaxRequestException e)
>> > {
>> > target = EmptyAjaxRequestTarget.getInstance();
>> > }
>> > }
>> > else
>> > {
>> > throw new PageExpiredException("Request cannot be processed");
>> > }
>> > }
>> > // See whether this request points to a shared resource
>> > else if (requestParameters.getResourceKey() != null)
>> > {
>> > target = resolveSharedResource(requestCycle, requestParameters);
>> > }
>> > // See whether this request points to the home page
>> > else if (Strings.isEmpty(path) || ("/".equals(path)))
>> > {
>> > target = resolveHomePageTarget(requestCycle, requestParameters);
>> > }
>> >
>> > // NOTE we are doing the mount check as the last item, so that it will
>> > // only be executed when everything else fails. This enables URLs like
>> > // /foo/bar/?wicket:bookmarkablePage=my.Page to be resolved, where
>> > // is either a valid mount or a non-valid mount. I (Eelco) am not
>> > // absolutely sure this is a great way to go, but it seems to have been
>> > // established as the default way of doing things. If we ever want to
>> > // tighten the algorithm up, it should be combined by going back to
>> > // unmounted paths so that requests with Wicket parameters like
>> > // 'bookmarkablePage' are always created and resolved in the same
>> > // fashion. There is a test for this in UrlMountingTest.
>> > if (target == null)
>> > {
>> > // still null? check for a mount
>> > target = requestCodingStrategy.targetForRequest(requestParameters);
>> >
>> > if (target == null && requestParameters.getComponentPath() != null)
>> > {
>> > // If the target is still null and there was a component path
>> > // then the Page could not be located in the session
>> > throw new PageExpiredException(
>> > "Cannot find the rendered page in session [pagemap=" +
>> > requestParameters.getPageMapName() + ",componentPath=" +
>> > requestParameters.getComponentPath() + ",versionNumber=" +
>> > requestParameters.getVersionNumber() + "]");
>> > }
>> > }
>> > else
>> > {
>> > // a target was found, but not by looking up a mount. check whether
>> > // this is allowed
>> > if (Application.get().getSecuritySettings().getEnforceMounts() &&
>> > requestCodingStrategy.pathForTarget(target) != null)
>> > {
>> > String msg = "Direct access not allowed for mounted targets";
>> > // the target was mounted, but we got here via another path
>> > // : deny the request
>> > log.error(msg + " [request=" + requestCycle.getRequest() + ",target="
>> +
>> > target +
>> > ",session=" + Session.get() + "]");
>> > throw new
>> > AbortWithWebErrorCodeException(HttpServletResponse.SC_FORBIDDEN, msg);
>> > }
>> > }
>> >
>> > // (WICKET-1356) in case no target was found, return null here.
>> > RequestCycle will deal with it
>> > // possible letting wicket filter to pass the request down the filter
>> > chain
>> > /*
>> > if (target == null)
>> > {
>> > // if we get here, we have no recognized Wicket target, and thus
>> > // regard this as a external (non-wicket) resource request on
>> > // this server
>> > return resolveExternalResource(requestCycle);
>> > }
>> > */
>> >
>> > return target;
>> > }
>> >
>> >
>> > --
>> > Pamir Erdem
>> >
>>
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>>
>
>
> --
> Pamir Erdem
>
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