Re: Asynchronous Components
I used the onBeforeRender/onRender methods and was able to implement the desired feature using Callable and Future objects from the java.concurrent API. Thanks a lot. Seb Igor Vaynberg wrote: if you want the page to render all at once you have to spin off as many threads as there are components and block rendering until all threads are done. you can do this in page#onbeforerender() which is called before any components start to render. the problem with this is that if it takes a while someone can easily dos your app because you are blocking servlet thread pool. a better way to do this would be to drop each component into an iframe and make it poll for data which is retrieved using some global threadpool. -igor On Tue, Jul 22, 2008 at 2:12 PM, Sebastian [EMAIL PROTECTED] wrote: Hi, I have not yet looked much into Wicket but am quite interested in the project. We have a specific requirement where I could not yet find the right information/documentation for. We need to put multiple components onto a page receiving data through web services. A single web services call takes some time. In our scenario it would be bad to have the different components of a page to request their data sequentially, therefore we'd like to have components retrieve the required data in parallel by firing the web services call concurrenlty. What is the best approach to achieve this (preferable in a generic, reusable fashion). I do not want to use AJAX for this, the whole page needs to be rendered at once on the server side. Thanks for any hints and thoughts in advance, Seb - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Asynchronous Components
Hi Sebastian, If you intend to use Wicket's default detachable models to get data from those services, they will be called sequentially. So those are out. I see 2 options: - In the panel constructor get the data in parallel threads through standard java 5 constructs (dump all your Callables in a ExecutorService and when that is done call get() on the returned Futures). When you have the data continue as normal. This approach is a bit easier then the next option, but only works with stateless pages (unless you known the data is not going to change soon anyway). - Write your own model (extend LoadableDetachableModel) that in the constructor will start a new thread to get the data (put a Callable in an ExecutorService and store the Future). Method load() should block until the thread is done (simply call get() on the Future). The base class will clear the data upon detach. Unfortunately, there is no onAttach() method that Wicket calls when the model data is needed again. To remedy this, you could call an onAttach() method yourself from onBeforeRender() in the component that uses the model. The onAttach method should do nothing when the data is already there, or a Future is already present (which means the data is already being retrieved). (I assume you have read a book on concurrency. If not you should, for example Java Threads.) Regards, Erik. Sebastian wrote: Hi, I have not yet looked much into Wicket but am quite interested in the project. We have a specific requirement where I could not yet find the right information/documentation for. We need to put multiple components onto a page receiving data through web services. A single web services call takes some time. In our scenario it would be bad to have the different components of a page to request their data sequentially, therefore we'd like to have components retrieve the required data in parallel by firing the web services call concurrenlty. What is the best approach to achieve this (preferable in a generic, reusable fashion). I do not want to use AJAX for this, the whole page needs to be rendered at once on the server side. Thanks for any hints and thoughts in advance, Seb - 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]
Re: Asynchronous Components
O, I forgot, be aware that Wicket does not really tolerate pages that take too long to render. Make sure that the page rendering does not take more then 60 seconds in total. (Luckily the Future#get method accepts a timeout argument.) Erik van Oosten wrote: ...dump all your Callables in a ExecutorService and when that is done call get() on the returned Futures... Regards, Erik. -- View this message in context: http://www.nabble.com/Asynchronous-Components-tp18598968p18607531.html Sent from the Wicket - User mailing list archive at Nabble.com. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Asynchronous Components
I think users are less forgiving than Wicket :) Martijn On Wed, Jul 23, 2008 at 12:05 PM, Erik van Oosten [EMAIL PROTECTED] wrote: O, I forgot, be aware that Wicket does not really tolerate pages that take too long to render. Make sure that the page rendering does not take more then 60 seconds in total. (Luckily the Future#get method accepts a timeout argument.) Erik van Oosten wrote: ...dump all your Callables in a ExecutorService and when that is done call get() on the returned Futures... Regards, Erik. -- View this message in context: http://www.nabble.com/Asynchronous-Components-tp18598968p18607531.html Sent from the Wicket - User mailing list archive at Nabble.com. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- Become a Wicket expert, learn from the best: http://wicketinaction.com Apache Wicket 1.3.4 is released Get it now: http://www.apache.org/dyn/closer.cgi/wicket/1.3. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Asynchronous Components
if you want the page to render all at once you have to spin off as many threads as there are components and block rendering until all threads are done. you can do this in page#onbeforerender() which is called before any components start to render. the problem with this is that if it takes a while someone can easily dos your app because you are blocking servlet thread pool. a better way to do this would be to drop each component into an iframe and make it poll for data which is retrieved using some global threadpool. -igor On Tue, Jul 22, 2008 at 2:12 PM, Sebastian [EMAIL PROTECTED] wrote: Hi, I have not yet looked much into Wicket but am quite interested in the project. We have a specific requirement where I could not yet find the right information/documentation for. We need to put multiple components onto a page receiving data through web services. A single web services call takes some time. In our scenario it would be bad to have the different components of a page to request their data sequentially, therefore we'd like to have components retrieve the required data in parallel by firing the web services call concurrenlty. What is the best approach to achieve this (preferable in a generic, reusable fashion). I do not want to use AJAX for this, the whole page needs to be rendered at once on the server side. Thanks for any hints and thoughts in advance, Seb - 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]
Re: Asynchronous Components
you may also consider using a portal framework and portlets, for example apache jetspeed portal (and possibly others) has parallel portlet rendering option.. Igor Vaynberg wrote: if you want the page to render all at once you have to spin off as many threads as there are components and block rendering until all threads are done. you can do this in page#onbeforerender() which is called before any components start to render. the problem with this is that if it takes a while someone can easily dos your app because you are blocking servlet thread pool. a better way to do this would be to drop each component into an iframe and make it poll for data which is retrieved using some global threadpool. -igor On Tue, Jul 22, 2008 at 2:12 PM, Sebastian [EMAIL PROTECTED] wrote: Hi, I have not yet looked much into Wicket but am quite interested in the project. We have a specific requirement where I could not yet find the right information/documentation for. We need to put multiple components onto a page receiving data through web services. A single web services call takes some time. In our scenario it would be bad to have the different components of a page to request their data sequentially, therefore we'd like to have components retrieve the required data in parallel by firing the web services call concurrenlty. What is the best approach to achieve this (preferable in a generic, reusable fashion). I do not want to use AJAX for this, the whole page needs to be rendered at once on the server side. Thanks for any hints and thoughts in advance, Seb - 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] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Asynchronous Components
Hi, I have not yet looked much into Wicket but am quite interested in the project. We have a specific requirement where I could not yet find the right information/documentation for. We need to put multiple components onto a page receiving data through web services. A single web services call takes some time. In our scenario it would be bad to have the different components of a page to request their data sequentially, therefore we'd like to have components retrieve the required data in parallel by firing the web services call concurrenlty. What is the best approach to achieve this (preferable in a generic, reusable fashion). I do not want to use AJAX for this, the whole page needs to be rendered at once on the server side. Thanks for any hints and thoughts in advance, Seb - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
