Nabble - DWR - Users

RE: Long time processing in the DwrServlet.service()

2008-05-13T06:51:35Z

> MW> I would suggest you try your application in a regular
> servlet engine,
> MW> like f ex Tomcat or Jetty, and report back if you still have any
> MW> problems. Reproducing your error in a "standard"
> environment will make
> MW> it much easier for other developers on the list to help you.
>
> Certainly it will be good, but unfortunately, I have not chance to do
> it easily. And it is why I ask you for ideas (potential solutions)
> about reason why/where DwrServlet keeps (can keep) request for a long
> time. And have not chance to debug it because of it is hard to
> reproduce this issue locally (with good network connection).

Ok, but be aware that you will get less help with an unknown
environment. It could be helpful if you deployed some of the DWR demo
apps on your custom environment, to see if you get the same problem
there (that would rule out one unknown variable = your application).

> I have no ideas how to localize the problem in a short term and why
> processing time the same with Comet request maximum connection time.

You need to provide a lot more information about your scenario:
- DWR version?
- Which request are you talking about? (Originating from a call on
a JavaScript proxy object or from a DWR Reverse Ajax poll?)
- Describe more about the call that you are timing, sequence of
operations, normal behaviour and expected times.
- Can you snoop and provide a HTTP log from when the problem appears?

Also think about this:
- DWR's Reverse Ajax request is designed to "hang" in the server
for one minute when in Full Streaming Mode. Is this what you are
seeing?
- Can you try the app with Reverse Ajax disabled, or try other
Reverse Ajax modes (Early Closing, Polling) ?
- Could you be hitting the Two Connections Limit?

> Maybe it is question to the developer mailing list, not sure...

No, the user list is appropriate for this.

> MW> BTW: What is your impression of Simple framework? (There
> doesn't seem
> MW> to have been much activity the last years.)
>
> Simple framework was an engine of the original application I started
> to support/rebuild several months ago. So, Simple framework was
> inherited from previous developers. But, as for me, it is a good
> solutions for project where you have a lot of _small_ requests to
> server. For example, JBoss creates separate thread for every
> connection and it is rather expensive operation if you have a lot of
> small AJAX requests from 1000 and more clients.

Yes, that makes sense. Although, JBOSS bundles Tomcat and Tomcat 6
supports non-blocking I/O which gets rid of the thread-per-connection
problem.

> Simple framework provides the article with comparisons of Simple's
> vs Apache and Resin.
> http://www.simpleframework.org/performance/comparison.php

Yes, I saw this article but all the software versions are quite
outdated so it would be interesting to see a comparison with modern
versions like Apache 2.2 Event MPM, Tomcat 6 NIO, etc.

Best regards
Mike

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Re: Nest List DWR Client Side Problem

2008-05-13T06:14:36Z

Nothing special. Why don't you send us some more specific information
(your dwr.xml and java class). Also you should check your server logs.

Nguyen, Thien 1 (N-Albin Engineering) wrote:

>
> I have a java POJO/Object that consists of nested LIST (2 levels). On
> the client side, using javascript, I always get an error when trying
> to get the innermost List. That is, I can retrieve the outermost List
> easily, but when I go deeper and get the innermost List, I get an
> “ERROR” on the DWR test page. Can someone give me an example on how to
> use nested LIST?
>
> Tim
>

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Re[2]: Long time processing in the DwrServlet.service()

2008-05-13T05:42:47Z

Greetings, Mike

MW> I would suggest you try your application in a regular servlet engine,
MW> like f ex Tomcat or Jetty, and report back if you still have any
MW> problems. Reproducing your error in a "standard" environment will make
MW> it much easier for other developers on the list to help you.

Certainly it will be good, but unfortunately, I have not chance to do
it easily. And it is why I ask you for ideas (potential solutions)
about reason why/where DwrServlet keeps (can keep) request for a long
time. And have not chance to debug it because of it is hard to
reproduce this issue locally (with good network connection).

I have no ideas how to localize the problem in a short term and why
processing time the same with Comet request maximum connection time.

Maybe it is question to the developer mailing list, not sure...

MW> BTW: What is your impression of Simple framework? (There doesn't seem
MW> to have been much activity the last years.)

Simple framework was an engine of the original application I started
to support/rebuild several months ago. So, Simple framework was
inherited from previous developers. But, as for me, it is a good
solutions for project where you have a lot of _small_ requests to
server. For example, JBoss creates separate thread for every
connection and it is rather expensive operation if you have a lot of
small AJAX requests from 1000 and more clients.

Simple framework provides the article with comparisons of Simple's
vs Apache and Resin. http://www.simpleframework.org/performance/comparison.php

And it is not bad approach for Web2.0 applications where you have one
main page and other content is generated dynamically. And when you
need to provide high interactively with server using AJAX requests.

Also, about Simple framework community: Mailing list is not very
active. But you can receive the helpful answer/suggestion for your
question rather quickly.

Thank you

>> I am using DWR with Simple framework
>> (http://www.simpleframework.org/). It has own Simple API which is
>> different from servlet-api. But I use Adaptor pattern to convert
>> simple.Request to HttpServletRequest and HttpServletResponse
>> to simple.Response.
>>
>> Also I am using Reverse Ajax in my web application.
>>
>> Simple request handler receives request and forwards it to the DWR
>> Servlet using DwrServlet.service(request, response) method. DWR
>> Servlet configured properly and it works.
>>
>> Sometimes I have strange behavior: request is being processed
>> 1 minute but
>> method on the class mapped to javascript works only 10 msec.
>>
>> I received this statistic wrapping DwrServlet.service with timer1 and
>> adding timer2 to the my Java class.
>>
>> timer1.maximum value = 1 minute (The maximum time is the same
>> as maximum time for Reverse Ajax request)
>> timer2.maximum value = 10 msec.
>>
>> This situation is hard to reproduce in my local version of the
>> application. But I have this statistic often in the live system. So it
>> is hard to debug it.
>>
>> It seems the number of these errors depends on browser (can't
>> reproduce it with FireFox) and connection quality. (Not sure).
>>
>> Have you idea where the request can be 60 sec in the
>> DwrServlet.service?
>>
>> Thanks in advance.

--
Best regards,
Dmitry Kudrenko
ARDAS group (http://www.ardas.dp.ua)

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RE: Long time processing in the DwrServlet.service()

2008-05-13T04:46:40Z

Hi Dmitry,

I would suggest you try your application in a regular servlet engine,
like f ex Tomcat or Jetty, and report back if you still have any
problems. Reproducing your error in a "standard" environment will make
it much easier for other developers on the list to help you.

BTW: What is your impression of Simple framework? (There doesn't seem
to have been much activity the last years.)

Best regards
Mike Wilson

> -----Original Message-----
> From: Dmitry Kudrenko [mailto:dmitry@...]
> Sent: den 12 maj 2008 12:56
> To: users@...
> Subject: [dwr-user] Long time processing in the DwrServlet.service()
>
> Greetings
>
> I am using DWR with Simple framework
> (http://www.simpleframework.org/). It has own Simple API which is
> different from servlet-api. But I use Adaptor pattern to convert
> simple.Request to HttpServletRequest and HttpServletResponse
> to simple.Response.
>
> Also I am using Reverse Ajax in my web application.
>
> Simple request handler receives request and forwards it to the DWR
> Servlet using DwrServlet.service(request, response) method. DWR
> Servlet configured properly and it works.
>
> Sometimes I have strange behavior: request is being processed
> 1 minute but
> method on the class mapped to javascript works only 10 msec.
>
> I received this statistic wrapping DwrServlet.service with timer1 and
> adding timer2 to the my Java class.
>
> timer1.maximum value = 1 minute (The maximum time is the same
> as maximum time for Reverse Ajax request)
> timer2.maximum value = 10 msec.
>
> This situation is hard to reproduce in my local version of the
> application. But I have this statistic often in the live system. So it
> is hard to debug it.
>
> It seems the number of these errors depends on browser (can't
> reproduce it with FireFox) and connection quality. (Not sure).
>
> Have you idea where the request can be 60 sec in the
> DwrServlet.service?
>
> Thanks in advance.
>
> --
> Best regards,
> Dmitry Kudrenko
> ARDAS group (http://www.ardas.dp.ua)
>
>
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> To unsubscribe, e-mail: users-unsubscribe@...
> For additional commands, e-mail: users-help@...
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Nest List DWR Client Side Problem

2008-05-12T17:00:09Z

I have a java POJO/Object that consists of nested LIST (2 levels). On the client side, using javascript, I always get an error when trying to get the innermost List. That is, I can retrieve the outermost List easily, but when I go deeper and get the innermost List, I get an “ERROR” on the DWR test page. Can someone give me an example on how to use nested LIST?

Tim

RE: Version 2.0.4.rc1

2008-05-12T15:16:39Z

Joe, some feedback on the 2.0.4 codebase:

ContainerUtil.java:1788: container.addParameter("maxWaitAfterWrite", "500");
This doesn't seem to have any effect?
Pollhandler.java:148: alarms.add(new OutputAlarm(scriptSession, maxWaitAfterWrite));
We may end up here with maxWaitAfterWrite=-1 so parameter should be substituted for some chosen number in these cases?
web/WEB-INF/web.xml: "This enables full streaming mode."
... or Early Closing Mode with maxWaitAfterWrite=0 in IE

(Excuse me if I have misunderstood these parts.)

Best regards

Mike

RE: Input Read Failed / Failed HTTP POST

2008-05-12T14:38:56Z

My first guess is this not a DWR issue but rather a browser issue.
The error message is a typical app server message (Tomcat 4.1?)
because nothing is received on the server's socket. DWR just
passes the message along. IIRC I've seen this when refreshing a
page that is still loading, causing the the ongoing sending of
data to be aborted.

I see the second (faulty) request appears 30 secs after the first.
Is this your choice of poll time? What happens if you try say 10
or 100 secs?

Also search for IE bugs applicable for your version. There are a
number of different bugs relating to different combinations of
parameters (encoding type, transfer encoding, etc).

If still unlucky, post more info about your software versions and
see if someone can help here.

Best regards
Mike Wilson

> -----Original Message-----
> From: Chris Braun [mailto:cbb@...]
> Sent: den 19 april 2008 02:07
> To: users@...
> Subject: [dwr-user] Input Read Failed / Failed HTTP POST
>
> I'm receiving occasional "Input read failed" exceptions from the dwr
> servlet when my JS client polls for changes on the server. While it
> does not happen every time, it happens frequent enough that I
> was able
> to get an Ethereal capture of the transactions.
>
> It appears that somehow IE starts a POST request for the dwr
> call, but
> never actually posts the data (it doesn't seem to happen on
> FF). After
> the ~10 second timeout, dwr does what it's supposed to and
> times out the
> post request with the "Input read failed" exception. Below is an
> example of the captured HTTP transaction, the first request succeeds,
> while the second never actually posts the 259 bytes it claimed it was
> going to send, both were on the same socket and the socket is still
> active after the exception is returned. (The capture is from
> the client
> side so it's hard to blame network now).
>
> I am looking for people thoughts on what would cause the dwr
> request to
> start but never actually post the data.
>
> Thanks - Chris
>
> Please excuse my awful depiction of an ethereal capture
> represented in
> an email.
>
> > POST /oims/dwr/call/plaincall/ChangeQueueProxy.getChangedData.dwr
> HTTP/1.1
> > Accept: */*
> > Accept-Language: en-us
> > Referer: http://sunfire:8089/oims/index.jsp#Reports
> > Content-Type: text/plain
> > UA-CPU: x86
> > Accept-Encoding: gzip, deflate
> > User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT
> 5.1; .NET
> CLR 2.0.50727; .NET CLR 1.1.4322)
> > Host: sunfire:8089
> > Content-Length: 259
> > Connection: Keep-Alive
> > Cache-Control: no-cache
> > Cookie: gridSplitter_1=100;
> JSESSIONID=1853E064B9A2D7D780E970A0AD6B62A3
> >
> > callCount=1
> > page=/oims/index.jsp
> > httpSessionId=1853E064B9A2D7D780E970A0AD6B62A3
> > scriptSessionId=120DDA8CB4E0E5C4CDF77A1D6E5AADB0131
> > c0-scriptName=ChangeQueueProxy
> > c0-methodName=getChangedData
> > c0-id=0
> > c0-param0=number:58
> > c0-param1=number:552120343
> > batchId=400
> = HTTP/1.1 200 OK
> = Content-Type: text/javascript;charset=ISO-8859-1
> = Content-Length: 145
> = Date: Fri, 18 Apr 2008 21:51:41 GMT
> = Server: Apache-Coyote/1.1
> =
> = //#DWR-INSERT
> = //#DWR-REPLY
> = var s0=[];
> =
> dwr.engine._remoteHandleCallback('400','0',{changeList:s0,curr

entChangeNumber:58,reqChangeNumber:58});

> > POST /oims/dwr/call/plaincall/ChangeQueueProxy.getChangedData.dwr
> HTTP/1.1
> > Accept: */*
> > Accept-Language: en-us
> > Referer: http://sunfire:8089/oims/index.jsp#Reports
> > Content-Type: text/plain
> > UA-CPU: x86
> > Accept-Encoding: gzip, deflate
> > User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT
> 5.1; .NET
> CLR 2.0.50727; .NET CLR 1.1.4322)
> > Host: sunfire:8089
> > Content-Length: 259
> > Connection: Keep-Alive
> > Cache-Control: no-cache
> > Cookie: gridSplitter_1=100;
> JSESSIONID=1853E064B9A2D7D780E970A0AD6B62A3
> >
> = HTTP/1.1 200 OK
> = Content-Type: text/javascript;charset=ISO-8859-1
> = Content-Length: 332
> = Date: Fri, 18 Apr 2008 21:52:11 GMT
> = Server: Apache-Coyote/1.1
> =
> = //#DWR-REPLY
> = if (window.dwr) dwr.engine._remoteHandleBatchException({
> name:'org.directwebremoting.extend.ServerException',
> message:'Failed to
> read input' });
> = else if (window.parent.dwr)
> window.parent.dwr.engine._remoteHandleBatchException({
> name:'org.directwebremoting.extend.ServerException',
> message:'Failed to
> read input' });
>
>
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Long time processing in the DwrServlet.service()

2008-05-12T03:55:33Z

Greetings

I am using DWR with Simple framework
(http://www.simpleframework.org/). It has own Simple API which is
different from servlet-api. But I use Adaptor pattern to convert
simple.Request to HttpServletRequest and HttpServletResponse to simple.Response.

Also I am using Reverse Ajax in my web application.

Simple request handler receives request and forwards it to the DWR
Servlet using DwrServlet.service(request, response) method. DWR
Servlet configured properly and it works.

Sometimes I have strange behavior: request is being processed 1 minute but
method on the class mapped to javascript works only 10 msec.

I received this statistic wrapping DwrServlet.service with timer1 and
adding timer2 to the my Java class.

timer1.maximum value = 1 minute (The maximum time is the same as maximum time for Reverse Ajax request)
timer2.maximum value = 10 msec.

This situation is hard to reproduce in my local version of the
application. But I have this statistic often in the live system. So it
is hard to debug it.

It seems the number of these errors depends on browser (can't
reproduce it with FireFox) and connection quality. (Not sure).

Have you idea where the request can be 60 sec in the
DwrServlet.service?

Thanks in advance.

--
Best regards,
Dmitry Kudrenko
ARDAS group (http://www.ardas.dp.ua)

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Re: DWR Scalabilty And Early Closing Mode

2008-05-10T05:47:17Z

This is the same as with HttpSessions - there is a timeout, after which they are removed.

There is an experimental feature with v3, that registers an onunload handler to explicitly remove the session, however it is a little temperamental right now.

Joe.

On Thu, May 1, 2008 at 10:44 PM, r123 <ronberna@...> wrote:

Another question I have is with sessions. We use
serverContext.getScriptSessionsByPage("/test.html") to retrieve a Collection
of sessions that are accessing the page that we are sending data to. When I
first load this page the number of sessions ( I'm thinking these are script
sessions) in the Collection is 1. Each time I refresh the page the number
of sessions increments by 1. Is this normal? Once I refresh, should the
old session go away? What type of problems will this cause if the sessions
remain?

Thanks
r123

Joe Walker-3 wrote:
>
> The plan says that 3.0 (including Gears integration) will be out in June.
> That does seem optimistic though.
> Joe
>
> On Fri, Apr 11, 2008 at 4:03 PM, r123 <ronberna@...> wrote:
>
>>
>> How does DWR handle fault tolerance? Also is there any idea of when
>> Gears
>> may be integrated in DWR?
>>
>> Thanks
>> r123
>>
>> Joe Walker-3 wrote:
>> >
>> > On Tue, Apr 8, 2008 at 10:54 PM, r123 <ronberna@...> wrote:
>> >
>> >>
>> >> Thanks for the links. Will do some reading on this. Another question
>> >> that
>> >> came up were concerns about security as well as slow message
>> consumption
>> >> by
>> >> the client. Since DWR is residing within the application server, the
>> >> application servlet container should handle security correct? Also, I
>> >> think
>> >> I read somewhere that DWR security features can be integrated with
>> J2EE
>> >> role
>> >> based authentication.
>> >
>> >
>> > http://getahead.org/dwr/server/dwrxml/creators
>> > See the docs on the auth element.
>> >
>> >
>> >> As far as the slow message consumption, does DWR have anything to
>> handle
>> >> this? I'm guessing there is no mechanism for guaranteed message
>> delivery
>> >> to
>> >> the client as of yet correct? Sorry for asking so many questions.
>> Just
>> >> want to make sure we have as much info as possible on DWR in order to
>> >> ease
>> >> some individual concerns.
>> >
>> >
>> > We haven't finished the Gears integration yet. However that doesn't
>> imply
>> > that DWR is likely to lose messages. The Gears integration is more to
>> do
>> > with pathalogical cases like network instability.
>> >
>> > Joe.
>> >
>> >
>>
>> --
>> View this message in context:
>> http://www.nabble.com/DWR-Scalabilty-And-Early-Closing-Mode-tp16080860p16627858.html
>> Sent from the DWR - Users mailing list archive at Nabble.com.
>>
>>
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>
>

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View this message in context: http://www.nabble.com/DWR-Scalabilty-And-Early-Closing-Mode-tp16080860p16995077.html

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RE: Reverse AJAX and ie6

2008-05-09T02:37:56Z

Thank you for your reply.

I set maxWaitAfterWrite to -1, like in the demo. With 2.0.4.rc1, it worked like a charm in both ie and Firefox.

For the leak problem, I tried the clock demo, and it was still present with 2.0.4.rc1. To be sure, I tested with another computer, and I got no leak at all. So the problem must comes from ie, maybe a missing update or something like that. I will investigate on this side.

Thank you again for your help,

Damien

mikewse wrote:

I'm trying to use reverse ajax to publish online events to a web browser.
Everything works fine with firefox.

In ie6, I get a low update rate. The update period is equal to the parameter
I set in "maxWaitAfterWrite" (if I set 5000, the values are updated once
every 5 seconds).

This is because Firefox's and IE's XHR implementations behave differently;
the Firefox XHR supports streaming which lets HTTP response data become
available before the request is closed. In IE it only becomes available
after the request is closed.

The maxWaitAfterWrite parameter determines how long after writing response
data before the request is closed, and it is thus not until then that the
data will become available in IE.

Setting a lower value increase the update rate but then I get a "memory
hog", memory consumption of ie grows very fast until I minimize the window
(very strange behaviour).

We have fixed a number of memory leaks in 2.0.4 so could you please check
with the RC again? You may also want to try, and compare with, DWR's Reverse
Ajax Clock example that have been verified not to leak.

Best regards
Mike Wilson

Re: hello

2008-05-09T02:28:12Z

hello

2008/5/9 技术邮箱 <qj_2002@...>:

hello

2008-05-09

技术邮箱

Re: Enable Dynamically named checkbox

2008-05-09T02:27:38Z

You could either give each checkbox an id and dwr.util.byId(i + "cb").disabled = false

Or you can try
document.choiceForm[name].disabled = false

Cheers,
Lance.

2008/5/8 Lauren Riley <Lauren.Riley@...>:

I have a list of objects that have ID's. I'm creating a checkbox for each, naming the checkbox id+"cb" as I iterator through the list. I am disabling the checkboxes to begin with. At a certain point in time, I want to enable the checkboxes one at a time. Is that possible with DWR? This is what I have now and it is not working. Anybody know how I could do this in DWR or how I could tweak this code to work? Thank you...

function enableCheckbox(){
var id = dwr.util.getValue("selectOutbuilding");
var name = id+'cb';
document.choiceForm.+ name + .disabled = false;
}

<c:forEach items="${outbuildings}" var="building">
<input type="checkbox" name="${building.id}cb" disabled="true">${building.description}</><BR>
</c:forEach>

__________________________________________
The information contained in this message may be privileged and confidential and protected from disclosure. If you are not the intended recipient of this message, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message, and please delete it from your computer.

hello

2008-05-08T19:42:00Z

hello

2008-05-09

技术邮箱

Enable Dynamically named checkbox

2008-05-08T12:33:35Z

I have a list of objects that have ID's. I'm creating a checkbox for each, naming the checkbox id+"cb" as I iterator through the list. I am disabling the checkboxes to begin with. At a certain point in time, I want to enable the checkboxes one at a time. Is that possible with DWR? This is what I have now and it is not working. Anybody know how I could do this in DWR or how I could tweak this code to work? Thank you...

function enableCheckbox(){
var id = dwr.util.getValue("selectOutbuilding");
var name = id+'cb';
document.choiceForm.+ name + .disabled = false;
}

<c:forEach items="${outbuildings}" var="building">
<input type="checkbox" name="${building.id}cb" disabled="true">${building.description}</><BR>
</c:forEach>

__________________________________________
The information contained in this message may be privileged and confidential and protected from disclosure. If you are not the intended recipient of this message, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message, and please delete it from your computer.

Re: Re: Keep track of ScriptSessions for one browser

2008-05-08T07:44:34Z

getScriptSessionById is a method of ServerContext. Here's the javadoc (from 3.0 HEAD)

getScriptSessionById

ScriptSession getScriptSessionById(java.lang.String sessionId)

You can request access to a specific ScriptSession if you know it's ID.

Take care with this method because it allows actions from one browser to affect another which could be a bad thing. It is certainly a VERY BAD idea to let session id's from one browser escape into another.

Consider that it is entirely possible that the ScriptSession may timeout while you are holding a reference to it.

Parameters:: sessionId - The script session ID to lookup
Returns:: The ScriptSession for the given ID, or null if it does not exist

On Thu, May 8, 2008 at 4:18 PM, Lance Java <lance.java@...> wrote:

One solution is to implement your own script session manager which intercepts script session creation, adding attributes to the script session based on the http session.

Later on, a reverse ajax thread can then differentiate between script sessions by their attributes.

<servlet>
    <servlet-name>dwr-invoker</servlet-name>
    <display-name>DWR Servlet</display-name>
    <description>Direct Web Remoter Servlet</description>
    <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
    <init-param>
        <param-name>org.directwebremoting.extend.ScriptSessionManager</param-name>
        <param-value>foo.bar.MyScriptSessionManager</param-value>
    </init-param>
</servlet>

Not sure about looking up a script session by id... what's your use case?

Cheers,
Lance.
2008/5/8 Erlend Sobec <erlend.sobec@...>:
If this question has been asked so many times, I agree that it should definitely be in the FAQ. However, since it isn't, perhaps you could tell me where I can find the answer rather than just tell me that it's been answered. I did search and only found the solution for threads started by DWR, but in my case, the thread is NOT started by DWR so I can't just use WebContextFactory.get().getScriptSession().

Also, I asked where I can find info about the function getScriptSession(String id). Has that also been answered? If so where?

Thanks,

Erlend
On Wed, May 8, 2008 at 9:53 AM, Jose Noheda <jose.noheda@...> wrote:
> I think that we need a FAQ somewhere because this has been answered hundreds
> of times by now
> 
> On Wed, May 7, 2008 at 10:39 PM, Erlend Sobec <erlend.sobec@...> wrote:



> 
> > Is there a way to send back information to only one browser even though
> > multiple browsers are on the given page?
> >
> > My problem is that I have multiple users logged in accessing their data.



> > If there is an update for any given user, I don't want it to be sent to all
> > users currently logged in.
> >
> > I saw a post on how to deal with this if the thread is started by DWR, but



> > in my case it isn't.  Also, in the javadoc there is mention of
> > getScriptSession(String id) but I can't find the method anywhere.  Maybe I
> > could use this to determine which ScriptSession I need to send updates to.



> >
> > Thanks,
> >
> > Erlend
> >

Re: Re: Keep track of ScriptSessions for one browser

2008-05-08T07:18:09Z

One solution is to implement your own script session manager which intercepts script session creation, adding attributes to the script session based on the http session.

Later on, a reverse ajax thread can then differentiate between script sessions by their attributes.

<servlet>
    <servlet-name>dwr-invoker</servlet-name>
    <display-name>DWR Servlet</display-name>
    <description>Direct Web Remoter Servlet</description>
    <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
    <init-param>
        <param-name>org.directwebremoting.extend.ScriptSessionManager</param-name>
        <param-value>foo.bar.MyScriptSessionManager</param-value>
    </init-param>
</servlet>

Not sure about looking up a script session by id... what's your use case?

Cheers,
Lance.

2008/5/8 Erlend Sobec <erlend.sobec@...>:

If this question has been asked so many times, I agree that it should definitely be in the FAQ. However, since it isn't, perhaps you could tell me where I can find the answer rather than just tell me that it's been answered. I did search and only found the solution for threads started by DWR, but in my case, the thread is NOT started by DWR so I can't just use WebContextFactory.get().getScriptSession().

Also, I asked where I can find info about the function getScriptSession(String id). Has that also been answered? If so where?

Thanks,

Erlend
On Wed, May 8, 2008 at 9:53 AM, Jose Noheda <jose.noheda@...> wrote:
> I think that we need a FAQ somewhere because this has been answered hundreds
> of times by now
> 
> On Wed, May 7, 2008 at 10:39 PM, Erlend Sobec <erlend.sobec@...> wrote:


> 
> > Is there a way to send back information to only one browser even though
> > multiple browsers are on the given page?
> >
> > My problem is that I have multiple users logged in accessing their data.


> > If there is an update for any given user, I don't want it to be sent to all
> > users currently logged in.
> >
> > I saw a post on how to deal with this if the thread is started by DWR, but


> > in my case it isn't.  Also, in the javadoc there is mention of
> > getScriptSession(String id) but I can't find the method anywhere.  Maybe I
> > could use this to determine which ScriptSession I need to send updates to.


> >
> > Thanks,
> >
> > Erlend
> >

Re: Keep track of ScriptSessions for one browser

2008-05-08T07:11:52Z

If this question has been asked so many times, I agree that it should definitely be in the FAQ. However, since it isn't, perhaps you could tell me where I can find the answer rather than just tell me that it's been answered. I did search and only found the solution for threads started by DWR, but in my case, the thread is NOT started by DWR so I can't just use WebContextFactory.get().getScriptSession().

Also, I asked where I can find info about the function getScriptSession(String id). Has that also been answered? If so where?

Thanks,

Erlend

On Wed, May 8, 2008 at 9:53 AM, Jose Noheda <jose.noheda@...> wrote:

> I think that we need a FAQ somewhere because this has been answered hundreds
> of times by now
> 
> On Wed, May 7, 2008 at 10:39 PM, Erlend Sobec <erlend.sobec@...> wrote:

> 
> > Is there a way to send back information to only one browser even though
> > multiple browsers are on the given page?
> >
> > My problem is that I have multiple users logged in accessing their data.

> > If there is an update for any given user, I don't want it to be sent to all
> > users currently logged in.
> >
> > I saw a post on how to deal with this if the thread is started by DWR, but

> > in my case it isn't.  Also, in the javadoc there is mention of
> > getScriptSession(String id) but I can't find the method anywhere.  Maybe I
> > could use this to determine which ScriptSession I need to send updates to.

> >
> > Thanks,
> >
> > Erlend
> >

how to make the server aware of ReverseAjax

2008-05-08T02:34:51Z

Seems like i'm messing too much with connection limit problem. But, here goes my query.
In my application, i do "dwr.engine.setActiveReverseAjax(true)" and "dwr.engine.setActiveReverseAjax(false)" time-to-time to reduce the burden of keeping one permanent connection for reverse ajax even if the client does not need it.

I want my server also to be aware of this thing i.e, whether there is a reverse ajax connection with a client or not. Explicitly Calling the server is not a reliable approach. I want some sort of listener at the server end which keeps track of when ActiveReverseAjax has been set true/false.

Otherwise, can somebody suggest my some way to set ActiveReverseAjax true or false from server side only.

Plz somebody help me out.. Hey Joe, are you listening?

RE: Reverse AJAX and ie6

2008-05-08T01:54:13Z

I'm trying to use reverse ajax to publish online events to a web browser. Everything works fine with firefox.

In ie6, I get a low update rate. The update period is equal to the parameter I set in "maxWaitAfterWrite" (if I set 5000, the values are updated once every 5 seconds).

This is because Firefox's and IE's XHR implementations behave differently; the Firefox XHR supports streaming which lets HTTP response data become available before the request is closed. In IE it only becomes available after the request is closed.

The maxWaitAfterWrite parameter determines how long after writing response data before the request is closed, and it is thus not until then that the data will become available in IE.

Setting a lower value increase the update rate but then I get a "memory hog", memory consumption of ie grows very fast until I minimize the window (very strange behaviour).

We have fixed a number of memory leaks in 2.0.4 so could you please check with the RC again? You may also want to try, and compare with, DWR's Reverse Ajax Clock example that have been verified not to leak.

Best regards

Mike Wilson

RE: synchronizing the java function calls in DWR

2008-05-08T01:46:42Z

> There's the ordered setting on the DWR engine too... that I think
> would do it... I'm not clear if under the covers this makes
> XMLHttpRequest synchronous (usually bad) or if the engine just
> manages making it all asynchronous itself

DWR manages it asynchronously so you don't have to be worried about
synchronus XHRs.

Best regards
Mike

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Re: Keep track of ScriptSessions for one browser

2008-05-08T00:53:20Z

I think that we need a FAQ somewhere because this has been answered hundreds of times by now

On Wed, May 7, 2008 at 10:39 PM, Erlend Sobec <erlend.sobec@...> wrote:

Is there a way to send back information to only one browser even though multiple browsers are on the given page?

My problem is that I have multiple users logged in accessing their data. If there is an update for any given user, I don't want it to be sent to all users currently logged in.

I saw a post on how to deal with this if the thread is started by DWR, but in my case it isn't. Also, in the javadoc there is mention of getScriptSession(String id) but I can't find the method anywhere. Maybe I could use this to determine which ScriptSession I need to send updates to.

Thanks,

Erlend

Re: how to get linked collections from Hibernate to the client

2008-05-07T23:26:28Z

Hi Josh,

thanks a lot for the tip with

Hibernate.initialize()

It works like a charm. Only for many-to-many i have to think of something else.But that's not really the problem.

Greetings Martin

2008/5/7 Josh Holtzman <jholtzman@...>:

I had run into a similar issue when I was serializing hibernate proxies. I now avoid sending these proxies to the client for a variety of reasons, but if you're sure that you want to do this, you have a couple of options that I know of:

1) Manually initialize the proxies that you want access to in the client. In other words, loop through each folder and each sheet on the server, calling sheet.getTags().
2) Call Hibernate.initialize() on each folder object. I've found that this will recurse into all of the fields on the proxy, but according to the API it isn't guaranteed to navigate the entire object graph, so you may need to loop through all of the sheet objects anyway.

Good luck,
Josh

martin krüger wrote:
Hi everybody,

I'm getting a little headache at the moment because of my little test project. I'm writing a small test application using Hibernate and since yesterday also DWR. I already managed to request Collections from Hibernate and display them on the client with this lines:

<convert converter="hibernate3" match="com.topdesk.training.accounting.hibernate.pojos.Tag" />
<convert converter="collection" match="java.util.Collection"/>

The problem now is that i have in some POJOS collections of other POJOS.

example:
1 folder has zero or more sheets
1 sheet has zero or more tags
(which are stored in a collection)

When i request all sheets from the server i return a collection of sheets. That works perfectly. I want to display all sheets in a simple HTML table. Per sheet i also want to list all tags that belong to that sheet. The problem now is that the collection that holds all the tags per sheet is null. Is there another way (another option) that i missed to let DWR also return the collections that belong to one object?

Thanks a lot already for DWR. It's a really nice tool.

Keep track of ScriptSessions for one browser

2008-05-07T13:39:22Z

Is there a way to send back information to only one browser even though multiple browsers are on the given page?

My problem is that I have multiple users logged in accessing their data. If there is an update for any given user, I don't want it to be sent to all users currently logged in.

I saw a post on how to deal with this if the thread is started by DWR, but in my case it isn't. Also, in the javadoc there is mention of getScriptSession(String id) but I can't find the method anywhere. Maybe I could use this to determine which ScriptSession I need to send updates to.

Thanks,

Erlend

Re: how to resize image returned from dwr call bufferedImage

2008-05-07T13:01:02Z

Hi, XMaNIac,

Thanks for your response, I got it working now.

Dave

XMaNIaC wrote:

I haven't suffered this problem but if setting image width and height does
not work (I can't understand why really) in IWebMvc you can see code to
generate thumbnails on the fly

On Wed, May 7, 2008 at 5:31 PM, ddduuu <davidkdu@gmail.com> wrote:

>
> Hi, all,
> I can successfully display the images returned from dwr call as
> bufferedImage which is retrieved from database, my problem is that the
> image
> is too big to fit my javascript window, I want the image exactly to fit
> the
> window, and resize with the window on the browser without going back to
> call
> dwr java function again to recalculate, so I mean my javascript program
> can
> recalculate the size of the image, with setup like this:
>
> day1.jpg
>
> I can do that with javascript, but with the dwr retrieved image like this:
>
> /webapp/dwr/download/10ED6EDB38A3C797840F9AB2E2764FD2
>
> I can not set style with the size, if I do, it will not display anymore.
>
> Any suggestions for me in terms of what to do to resize it with
> javascript?
>
> Thanks in advance.
>
> Dave
> --
> View this message in context:
> http://www.nabble.com/how-to-resize-image-returned-from-dwr-call-bufferedImage-tp17106418p17106418.html
> Sent from the DWR - Users mailing list archive at Nabble.com.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@dwr.dev.java.net
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>
>

Re: how to resize image returned from dwr call bufferedImage

2008-05-07T08:58:34Z

I haven't suffered this problem but if setting image width and height does not work (I can't understand why really) in IWebMvc you can see code to generate thumbnails on the fly

On Wed, May 7, 2008 at 5:31 PM, ddduuu <davidkdu@...> wrote:

Hi, all,
I can successfully display the images returned from dwr call as
bufferedImage which is retrieved from database, my problem is that the image
is too big to fit my javascript window, I want the image exactly to fit the
window, and resize with the window on the browser without going back to call
dwr java function again to recalculate, so I mean my javascript program can
recalculate the size of the image, with setup like this:

day1.jpg

I can do that with javascript, but with the dwr retrieved image like this:

/webapp/dwr/download/10ED6EDB38A3C797840F9AB2E2764FD2

I can not set style with the size, if I do, it will not display anymore.

Any suggestions for me in terms of what to do to resize it with javascript?

Thanks in advance.

Dave
--
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how to resize image returned from dwr call bufferedImage

2008-05-07T08:31:48Z

Hi, all,
I can successfully display the images returned from dwr call as bufferedImage which is retrieved from database, my problem is that the image is too big to fit my javascript window, I want the image exactly to fit the window, and resize with the window on the browser without going back to call dwr java function again to recalculate, so I mean my javascript program can recalculate the size of the image, with setup like this:

img src="day1.jpg" title="day1.jpg." style="width: 115px; height: 126px; visibility: hidden;"

I can do that with javascript, but with the dwr retrieved image like this:

img id="image-day1.jpg" src="/webapp/dwr/download/10ED6EDB38A3C797840F9AB2E2764FD2" title="day1.jpg"

I can not set style with the size, if I do, it will not display the image anymore.

Any suggestions for me in terms of what to do to resize it with javascript?

Thanks in advance.

Dave

Re: synchronizing the java function calls in DWR

2008-05-07T08:01:07Z

There's the ordered setting on the DWR engine too... that I think would
do it... I'm not clear if under the covers this makes XMLHttpRequest
synchronous (usually bad) or if the engine just manages making it all
asynchronous itself, which would mean the UI probably wouldn't lock up
and it might be acceptable... there's a separate async setting that
according to the docs does make XMLHttpRequest synchronous (or not)...
playing with ordered might be worth a shot.

--
Frank W. Zammetti
Author of "Practical DWR 2 Projects"
and "Practical JavaScript, DOM Scripting and Ajax Projects"
and "Practical Ajax Projects With Java Technology"
for info: apress.com/book/search?searchterm=zammetti&act=search
Java Web Parts - javawebparts.sourceforge.net
Supplying the wheel, so you don't have to reinvent it!
My "look ma, I have a blog too!" blog: zammetti.com/blog

FrankJose Noheda wrote:

> call it in the callback of the first one. there are other means but
> they're not as reliable. with gears integration things could improve in
> this area
>
> On Wed, May 7, 2008 at 3:58 PM, Nitin Thakur <myegotrip@...
> <mailto:myegotrip@...>> wrote:
>
>
> Is there any way to synchronize java-function-calls from javascript
> without
> server explicitly sending acknowledgment through reverse Ajax. Say,
> i want
> to make a call to method2 (JavaClass.method2) only after my previous
> call
> has been completed (JavaClass.method1). is there any way to assure this.
> --
> View this message in context:
> http://www.nabble.com/synchronizing-the-java-function-calls-in-DWR-tp17105611p17105611.html
> Sent from the DWR - Users mailing list archive at Nabble.com.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@...
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>
>

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Re: synchronizing the java function calls in DWR

2008-05-07T07:51:14Z

call it in the callback of the first one. there are other means but they're not as reliable. with gears integration things could improve in this area

On Wed, May 7, 2008 at 3:58 PM, Nitin Thakur <myegotrip@...> wrote:

Is there any way to synchronize java-function-calls from javascript without
server explicitly sending acknowledgment through reverse Ajax. Say, i want
to make a call to method2 (JavaClass.method2) only after my previous call
has been completed (JavaClass.method1). is there any way to assure this.
--
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synchronizing the java function calls in DWR

2008-05-07T06:58:47Z

Is there any way to synchronize java-function-calls from javascript without server explicitly sending acknowledgment through reverse Ajax. Say, i want to make a call to method2 (JavaClass.method2) only after my previous call has been completed (JavaClass.method1). is there any way to assure this.

Re: how to get linked collections from Hibernate to the client

2008-05-07T06:29:31Z

I had run into a similar issue when I was serializing hibernate proxies. I now avoid sending these proxies to the client for a variety of reasons, but if you're sure that you want to do this, you have a couple of options that I know of:

1) Manually initialize the proxies that you want access to in the client. In other words, loop through each folder and each sheet on the server, calling sheet.getTags().
2) Call Hibernate.initialize() on each folder object. I've found that this will recurse into all of the fields on the proxy, but according to the API it isn't guaranteed to navigate the entire object graph, so you may need to loop through all of the sheet objects anyway.

Good luck,
Josh

martin krüger wrote:

Hi everybody,

I'm getting a little headache at the moment because of my little test project. I'm writing a small test application using Hibernate and since yesterday also DWR. I already managed to request Collections from Hibernate and display them on the client with this lines:

<convert converter="hibernate3" match="com.topdesk.training.accounting.hibernate.pojos.Tag" />
<convert converter="collection" match="java.util.Collection"/>

The problem now is that i have in some POJOS collections of other POJOS.

example:
1 folder has zero or more sheets
1 sheet has zero or more tags
(which are stored in a collection)

When i request all sheets from the server i return a collection of sheets. That works perfectly. I want to display all sheets in a simple HTML table. Per sheet i also want to list all tags that belong to that sheet. The problem now is that the collection that holds all the tags per sheet is null. Is there another way (another option) that i missed to let DWR also return the collections that belong to one object?

Thanks a lot already for DWR. It's a really nice tool.

Reverse AJAX and ie6

2008-05-07T06:11:41Z

Hi,

I'm trying to use reverse ajax to publish online events to a web browser. Everything works fine with firefox.

In ie6, I get a low update rate. The update period is equal to the parameter I set in "maxWaitAfterWrite" (if I set 5000, the values are updated once every 5 seconds). Setting a lower value increase the update rate but then I get a "memory hog", memory consumption of ie grows very fast until I minimize the window (very strange behaviour).

The memory problem seems to be triggered by javascript method call on the java side. I tried to disable all my application logic, but the problem persists.

I tried severeral version of DWR (from 2.0.1 to 2.0.4rc1) with no luck. My web application is based on Spring and is deployed on a Jetty6 web server.

Any ideas ? Maybe I am doing something wrong ?

Damien

DWR Dinner

2008-05-07T05:24:51Z

If you're at JavaOne, and fancy a meal, or just a few beers, we could all hook up after the comet talk this evening. The talk is in 307-310 and from 6:30 to 7:20.
It would be good to meet up, and I'll buy at least the first round.

Joe.

RE: getting form FORM to Java Object (JSF)

2008-05-07T01:35:29Z

> Now I tried the table editing example of DWR with
> dwr 2.0.1 (appfuse-jsf 2.0). It works well, but when I change the
>
> <input id="name"
>
> to
>
> <h:inputText id="name" (JSF)
>
> And the resulting HTML source prefix "j_id2:" with the JSF
> component.
>
> <input id="j_id2:name" name="j_id2:name" type="text" value="" />
> <input id="salary" type="text" size="20" />
> <input type="text" id="address" size="40" />
>
> The dwr.util.setValues(person) is not showing the name field value.

Ok, your problem here is with JSF's generated id/name attributes. Your
specified id="name" is prepended with a parent's id acting as naming
container.

As DWR's get/setValue[s] functions are purely client-side implementations,
and not dependent on your server-side framework, they can only consider
the resulting id/name and these are now different from the property names
in your person object.

Possible solutions:

1) Ask JSF not to rewrite the ids on these elements. I'm by no means a JSF
expert but I've seen this:
JSF 1.2: form prependId=false
Myfaces: input forceId=true
Check what your chosen JSF implementation can offer. It's probably
better to ask further questions on this subject in a JSF forum but it
would be nice if you can report back your findings here.
[Not rewriting the ids assume you don't have any other elements with
the same id that may interfere.]

2) Change the members of your person object to match the generated ids.
Probably not desired, but anyway:
person["j_id2:name"] = "Donald";
dwr.util.setValues(person);

3) Use setValue calls for every property instead of setValues:
dwr.util.setValue("j_id2:name", person.name);
... etc ...

4) Updating setValues() in 2.0.4 as it currently has almost the support
you need:
dwr.util.setValues(person, {prefix:"j_id2"});
The above will map
person.name -> id "j_id2.name"
and so forth. Note the separating dot instead of colon. We could add
a new option for configuring the separator character:
dwr.util.setValues(person, {prefix:"j_id2",separator:":"});
that would then map
person.name -> id "j_id2:name"
What does everybody think - is this the correct (and desired) way
of tackling this issue or is the JSF id thingie too complex to
handle properly anyway, and should be avoided?

Best regards
Mike

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how to get linked collections from Hibernate to the client

2008-05-07T01:13:40Z

Hi everybody,

I'm getting a little headache at the moment because of my little test project. I'm writing a small test application using Hibernate and since yesterday also DWR. I already managed to request Collections from Hibernate and display them on the client with this lines:

<convert converter="hibernate3" match="com.topdesk.training.accounting.hibernate.pojos.Tag" />
<convert converter="collection" match="java.util.Collection"/>

The problem now is that i have in some POJOS collections of other POJOS.

example:
1 folder has zero or more sheets
1 sheet has zero or more tags
(which are stored in a collection)

When i request all sheets from the server i return a collection of sheets. That works perfectly. I want to display all sheets in a simple HTML table. Per sheet i also want to list all tags that belong to that sheet. The problem now is that the collection that holds all the tags per sheet is null. Is there another way (another option) that i missed to let DWR also return the collections that belong to one object?

Thanks a lot already for DWR. It's a really nice tool.