one more thing: I also ran the code without the piece that retrieves
web pages and gets their length. Instead I just had the Calculator
class sleep for 10 seconds (which is longer than the http request
takes) and then return a random number. This worked fine. I can't see
what the difference is.
On Nov 11, 11:26 pm, Jack Widman <jack.wid...@gmail.com> wrote:
> David,
>
> I have attached my code. It runs but does not behave as I intended it to.
> The code does a web search on the term "scala" and displays a list of URLs
> of the results. Next to each URL it says "Page Length : -1". A process is
> running in the background which takes each URL, goes out and gets the page
> and takes the length of the page. The length of that page is then supposed
> to immediately appear on the page next to that URL. I put the lengths on a
> queue, as they come in, and I have the Comet page poll the queue and display
> the results. It would probably be better to have the results send a message
> to the Comet class so the page is only re-rendered when there is a change
> but for now I am polling.
>
> I can see the lengths coming in and being put on the queue, but the Comet
> page is not getting them till they are all retrieved. (This takes way too
> long and nothing changes on the screen till its too late). I need them to
> appear as they come in. Occasionally I can see a length being retrieved and
> the Comet page finds it but even then it is not displayed until all the
> lengths are in. I know this is not very clear but I think it will be clear
> from the code.
>
> I also know there are a lot of places in the code which can be improved and
> I welcome all of your input but what I would love is to have these numbers
> appear on the page as they they are retrieved. I have been stumped by this
> for a while and I suspect that somebody who knows Lift well might see the
> problem right away.
>
> The class that retrieves the page lengths is called Calculator and the queue
> is called SourceQueue. The classes are pretty small so hopefully it will be
> clear what is going on. I want you to know I think it is incredible how
> responsive you and the group are and I look forward to using Lift in the
> future.
>
> Thanks so much.
>
> Jack
>
> On Tue, Nov 10, 2009 at 1:27 AM, David Pollak <feeder.of.the.be...@gmail.com
>
> > wrote:
>
> > On Mon, Nov 9, 2009 at 10:10 PM, Jack Widman <jack.wid...@gmail.com>wrote:
>
> >> The only difference between your working code and mine is that mine has a
> >> process in the background that is always running and puts Foo objects on a
> >> queue whenever they are ready. Where can I start this long running process
> >> so that it doesn't interfere with the lowPriority method that takes things
> >> off the queue and rerenders the page. I tried starting the process in its
> >> own Actor that I start in localSetup but it seems somehow to be blocking
> >> the
> >> lowPriority method from doing its thing.
>
> > I have no idea what this means... sorry.
>
> > Please post actual runnable code and we can help you debug.
>
> >> On Sun, Nov 8, 2009 at 11:35 PM, David Pollak <
> >> feeder.of.the.be...@gmail.com> wrote:
>
> >>> Jack,
>
> >>> I reproduced your code and it seems to work fine. I've enclosed a
> >>> working copy.
>
> >>> Some comments about your code:
>
> >>> - The foos variable and the foo variable may be getting confused in
> >>> the code... the render method may be rendering the same thing based on
> >>> the
> >>> unchanging foos variable.
> >>> - Doing null testing is a sign that you have logic errors in your
> >>> code. I strongly recommend using either Box or Option for everything
> >>> that
> >>> can logically not contain a value/reference. If you're bridging out
> >>> to Java
> >>> code and are expecting null from the Java code, write a small bridge
> >>> that
> >>> will wrapper the Java return values in Box/Option.
> >>> - You have a case class (Tick) that contains no parameters. Please
> >>> use a case object instead.
> >>> - Your Tick look is a spin loop. You fire a Tick message as part of
> >>> processing the Tick message. I would suggest that if you're polling,
> >>> that
> >>> you have a reasonable poll interval, otherwise you'll starve your CPU.
> >>> Further, having reRender on each loop through means that you're
> >>> forcing a
> >>> lot of bytes over the wire rather than only doing a reRender on changed
> >>> values.
>
> >>> Thanks,
>
> >>> David
>
> >>> On Sun, Nov 8, 2009 at 3:47 PM, Jack Widman <jack.wid...@gmail.com>wrote:
>
> >>>> Sorry. Here it is: As I said, I know that when render is called,
> >>>> foo.getValue has the right value. But it does not show on the screen,
> >>>> unless
> >>>> I refresh the browser.
>
> >>>> package com.foo.comet
>
> >>>> import net.liftweb._
> >>>> import http._
> >>>> import js._
> >>>> import JsCmds._
> >>>> import net.liftweb.util._
> >>>> import net.liftweb.http._
> >>>> import _root_.scala.xml._
> >>>> import scala.actors._
> >>>> import com.authoritude.snippet._
> >>>> import scala.collection.mutable.Queue
> >>>> import net.liftweb.http.SessionVar
>
> >>>> class MyComet extends CometActor {
>
> >>>> override def defaultPrefix = Full("auth")
>
> >>>> private var foos = FooManager.getFoos
>
> >>>> def createDisplay(foos:List[Foo]):NodeSeq = {
> >>>> <span id="go"><table>
> >>>> {
> >>>> for {foo <- foos} yield <tr><td>{foo.getValue}</td></tr>
> >>>> }
>
> >>>> </table></span>
> >>>> }
>
> >>>> def render = { bind("foo" -> createDisplay(foos)) }
>
> >>>> override def localSetup = {
> >>>> super.localSetup
> >>>> this ! Tick
> >>>> }
>
> >>>> var foo:Foo = null
> >>>> override def lowPriority = {
> >>>> case Tick => {
> >>>> foo=FooQueue.getLatest
> >>>> if (foo!=null && foo.getValue > -1) {
> >>>> blogs = FooManager.process(foo, foos)
> >>>> } else if (foo!=null){
> >>>> foos = foos.remove((f:Foo)=>(f.id==foo.id))
> >>>> }
> >>>> reRender(false)
> >>>> this ! Tick
> >>>> }
> >>>> }
> >>>> }
>
> >>>> case class Tick
>
> >>>> On Sun, Nov 8, 2009 at 5:31 AM, Timothy Perrett <
> >>>> timo...@getintheloop.eu> wrote:
>
> >>>>> Without posting your code it's going to be tough to help you.
>
> >>>>> Cheers, Tim
>
> >>>>> Sent from my iPhone
>
> >>>>> On 8 Nov 2009, at 08:14, jack <jack.wid...@gmail.com> wrote:
>
> >>>>> > By the way, I know that when render is called, all the variables have
> >>>>> > the right values. I just don't see it on the screen unless I refresh
> >>>>> > it.
>
> >>>>> > On Nov 8, 3:12 am, jack <jack.wid...@gmail.com> wrote:
> >>>>> >> I have a CometActor. render is called when it is supposed to be but
> >>>>> I
> >>>>> >> don't see the changes. If I refresh the page at anytime, I do see
> >>>>> the
> >>>>> >> changes. Any idea what might cause this?
>
> >>>> --
> >>>> Jack Widman
>
> >>>> co-founder / cto, Authoritude, Inc.
>
> >>>> 203-641-9355
>
> >>> --
> >>> Lift, the simply functional web frameworkhttp://liftweb.net
> >>> Beginning Scalahttp://www.apress.com/book/view/1430219890
> >>> Follow me:http://twitter.com/dpp
> >>> Surf the harmonics
>
> >> --
> >> Jack Widman
>
> >> co-founder / cto, Authoritude, Inc.
>
> >> 203-641-9355
>
> > --
> > Lift, the simply functional web frameworkhttp://liftweb.net
> > Beginning Scalahttp://www.apress.com/book/view/1430219890
> > Follow me:http://twitter.com/dpp
> > Surf the harmonics
>
>
>
> widman.tgz
> 187KViewDownload
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