Hi,

Forgot: you can use Thread.sleep() to wait (java.lang.Thread is also
part of the JRE)

regards

didier

On Jan 29, 3:35 pm, Didier Durand <[email protected]> wrote:
> Hi,
>
> LinkedBlokingQueue is part of JRE 
> WhiteList:http://code.google.com/appengine/docs/java/jrewhitelist.html. So, 
> you
> can use it.
>
> But, I dont see the need. Why don't you just from on the datastore on
> 1 side and read from it on the other. It would be very simple and rely
> on the most basic (i.e solid) mechanism of gae. (I would recommend
> Objectify for ds read/ write)
>
> As you have network round-trips, the read / write time will be
> negligible even it can seem high compared to an in-memory mechanism
> like a Queue.
>
> regards
>
> didier
>
> On Jan 29, 1:51 pm, arturad <[email protected]> wrote:
>
> > In my application an embedded device (no public IP) should connect to
> > the GAE in order to obtain some data from it. The data are provided by
> > the web browser.
>
> > The whole data-passing process looks like:
>
> >                                               web browser -> GAE ->
> > embedded standalone device
>
> > I developed a servlet the device connects to. It issues the HTTP GET.
> > On the other side the web browser sends data using standard GWT
> > RemoteServiceServlet.
>
> > In case there is no data for the device the doGet method in the
> > servlet should stop for some seconds until user enters data or time
> > out expires.
>
> > I'm trying to use LinkedBlockingQueue  to pass data between two
> > servlets. It does not work unfortunately. Seems like the GAE launches
> > new JVM for concurrent requests... I pushed the LinkedBlockingQueue
> > into memcache and get it by name from concurrent requests. Still does
> > not work. Memcache returns NOTnull. But there are no data in the
> > queue.
>
> > In order to investigate my issue I've made some tests with the
> > semaphore. Pushed the semaphore to the memcache and made some
> > concurrent operations ... -> does not work -> one process does not
> > release the other...
>
> > The problem occurs on GAE only. The whole mechanism works on the
> > development server.
>
> > Is there any way to stop/freeze one process (in the doGet method in
> > servlet) and unblock it by another one ?
>
> > Or... Is there any other way to solve my problem ?
> > Thank you for any suggestions.
> > Artur
>
>

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