Hi
Take a look at the polling consumer EIP pattern
http://camel.apache.org/polling-consumer.html
It allows you to poll messages on-demand from any Camel endpoint.
And you can use the ConsumerTemplate API to do it from a few lines of code.
Then you do not need any Camel routing, etc.
On Tue, Jan 3, 2012 at 3:48 PM, David Wynter <david_wyn...@yahoo.com> wrote:
> Hi,
>
> I implemented my HaltProcessor. But it still does not behave as I thought. I
> could not see where in the documentation it explains the route behaviour for
> shutdown. I have this:
>
> String sourcePath = createFromUri();
> if(sourcePath == null)
> return;
> String to = localName.length()>0?localName:"";
> RouteDefinition routeD = new RouteDefinition();
> routeD.from(sourcePath);
>
> routeD.to(localPath+"?fileExist=Override");
> HaltProcessor pHalt = new HaltProcessor();
> pHalt.setContext(camelContext);
> routeD.routeId(sourcePath);
> pHalt.setRouteId(sourcePath);
> routeD.process(pHalt);
> camelContext.addRouteDefinition(routeD);
>
> camelContext.startRoute(routeD);
>
> where Halt Processor has this process method body:
>
> if(context!=null && routeId != null) {
> // remove myself from the in flight registry so we can stop this
> route without trouble
> context.getInflightRepository().remove(exchange);
> // stop this route
> context.stopRoute(routeId);
>
> My problem is this. The startRoute occurs and starts the route then
> immediately hits the HaltProcessor. It hits the HaltProcessor before
> completing the ftp download, which might be a 2KB file or a hundred 1MB
> files. Then it all exits and my next task in a workflow executes. It depends
> on the file being completely downloaded from the download the route provides.
> But it seems the calling thread is terminated but some other thread continues
> the task of doing the download, this isn't completed by the time the route
> returns.
>
> My requirement is simple, download the file from ftp, do not return until
> this is done, do it once only, do not poll, just return at this point. Do I
> need my own ShutdownStrategy for this simple requirement, if so, is there a
> listener I can setup to know the file has completed the download?
>
> A separate problem is even using noop=true it still polls.
>
> Thx.
>
> David
>
>
>
> ________________________________
> From: Taariq Levack <taar...@gmail.com>
> To: "users@camel.apache.org" <users@camel.apache.org>
> Sent: Thursday, 29 December 2011, 19:35
> Subject: Re: NPE for FTP endpoint
>
> The processor[1] is exactly that class so give it a try, also see the file
> language [2] for dynamically setting filename.
>
> [1] http://camel.apache.org/processor.html
> [2] http://camel.apache.org/file-language.html
>
> On 29 Dec 2011, at 9:14 PM, David Wynter <david_wyn...@yahoo.com> wrote:
>
>> Hi,
>>
>> Yes it is a dynamic path for producer and consumer. Restricted in this case
>> as ftp to file or in another case from file to ftp. This use case is very
>> restricted, my intent is to use Camel in a less restricted way in another
>> use case from within this same application later, otherwise I would have
>> just used FTPClient
>>
>> So you are saying I just need a class in the route that has access to the
>> exchange to be able to stop it. I'll have a dig around in the JavaDoc to see
>> what I can find. Are there more examples somewhere of how to use the API?
>>
>> Thx.
>>
>>
>> ________________________________
>> From: Taariq Levack <taar...@gmail.com>
>> To: "users@camel.apache.org" <users@camel.apache.org>
>> Sent: Thursday, 29 December 2011, 18:56
>> Subject: Re: NPE for FTP endpoint
>>
>> Why do you want to create a processor definition that way?
>> The example only uses the processor to illustrate the point, it has access
>> to the exchange and can easily remove it from the inflight repo of the camel
>> context.
>> To do it your way I don't know without an IDE handy, I avoid working with
>> low level camel API in my apps, so maybe first try to avoid it in this case
>> or help me understand why you need it.
>>
>> Maybe you're only doing this to set a dynamic path for the consumer and
>> producer?
>>
>> Taariq
>>
>> On 29 Dec 2011, at 8:26 PM, David Wynter <david_wyn...@yahoo.com> wrote:
>>
>>> Ok, I misunderstood the "Stopping a route during routing an existing
>>> message is a bit tricky. The reason for that is Camel will Graceful
>>> Shutdown the route you are stopping. And if you do that while a message is
>>> being routed the Graceful Shutdown will try to wait until that message has
>>> been processed." Which made me think the Processor method described an
>>> alternate way and therefore would stop the route during the message
>>> transfer. In fact you are saying it is an equivalent operation, I think.
>>>
>>> Since I am doing this in code I am not sure which of the many impl of
>>> ProcessDefinition I should be adding to a RouteContext and then adding to
>>> the Route.
>>>
>>> Is it like this?
>>>
>>> RouteDefinition routeD = new RouteDefinition();
>>> routeD.from(sourcePath);
>>>
>>> routeD.to(localPath+"?fileExist=Override");
>>> RouteContext rContext = new DefaultRouteContext(camelContext);
>>> ProcessorDefinition pDefn = ?
>>> rContext.createProcessor(pDefn);
>>> routeD.createProcessor(rContext);
>>> routeDefn.put(sourcePath+localPath+"?fileExist=Override", routeD);
>>> camelContext.addRouteDefinition(routeD);
>>> camelContext.startRoute(routeD);
>>>
>>> Not sure which ProcessorDefinition type I need.
>>>
>>> Thx.
>>>
>>> David
>>>
>>> ________________________________
>>> From: Taariq Levack <taar...@gmail.com>
>>> To: "users@camel.apache.org" <users@camel.apache.org>
>>> Sent: Thursday, 29 December 2011, 17:50
>>> Subject: Re: NPE for FTP endpoint
>>>
>>> Hmmm, can you talk more about your use case?
>>> Because the FAQ seems a perfect fit, you consume the file and then stop the
>>> route, later it starts again in whatever way you want.
>>>
>>> No idea on the NPE, sorry.
>>>
>>> Taariq
>>>
>>> On 29 Dec 2011, at 7:29 PM, David Wynter <david_wyn...@yahoo.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I do not want to stop the route mid flight as that FAQ seems to be
>>>> suggesting. I would be happy to use DefaultShutdownStrategy, if it worked.
>>>> My problem is that it is inconsistent, which seems bad design, on a slow
>>>> machine the route is not considered started by the time I hit the
>>>> stopRoute, whereas on a fast machine it is considered started. I even used
>>>> Thread delays but that did not give consistent results either. Thus I
>>>> decided to leave the route running, but that polls the server, a no no
>>>> with this service provider. There does not seem a way to just do it once
>>>> and then be certain the fetch has occurred before stopping the route to
>>>> prevent the polling. I'd like to poll until my fetch from the ftp server
>>>> is complete, and then stop polling and stop the route, I'll start it again
>>>> when I am ready. There does not seem to be a way of adding a listener to
>>>> the route to ask it, "hey have you actually completed the route for the
>>>> file specified?" The only way
> I
>>>> can think of doing this is adding a custom endpoint as a next step, this
>>>> custom endpoint then calls for the route to be stopped.
>>>>
>>>> But these are the least of my worries since on my customers machine I get
>>>> the NPE, but in testing here I do not? Any ideas on this NPE?
>>>>
>>>> Thx.
>>>>
>>>> David
>>>>
>>>>
>>>> ________________________________
>>>> From: Taariq Levack <taar...@gmail.com>
>>>> To: "users@camel.apache.org" <users@camel.apache.org>
>>>> Sent: Thursday, 29 December 2011, 17:14
>>>> Subject: Re: NPE for FTP endpoint
>>>>
>>>> Hi
>>>>
>>>> Did you try this FAQ[1] on how to stop a route from a route?
>>>> [1] http://camel.apache.org/how-can-i-stop-a-route-from-a-route.html
>>>>
>>>> Taariq
>>>>
>>>> On 29 Dec 2011, at 6:12 PM, David Wynter <david_wyn...@yahoo.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I tested on my machine and deployed to my customer, It went boom as
>>>>> follows, names etc. changed to protect the innocent.
>>>>>
>>>>> All I want to do with this route is grab a file from a ftp service, once,
>>>>> don't poll it annoys them, leave the file intact on their server. I will
>>>>> control when this route is run externally. I tried it with start() follow
>>>>> by stop(),
>>>>>
>>>>> camelContext.addRouteDefinition(routeD);
>>>>> camelContext.startRoute(routeD);
>>>>> but the DefaultShutdownStrategy is flaky, on a slow machine it does not
>>>>> consider the route started before the stop() is hit, whereas on a fast
>>>>> machine it does. So I am forced to leave the route running
--
Claus Ibsen
-----------------
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Email: cib...@fusesource.com
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