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Posted to users@camel.apache.org by davsclaus <ci...@yahoo.dk> on 2008/11/01 09:41:18 UTC

Re: Multicast with choice

Hi

A bit late with the answer, but Camel uses Pipeline (pipes and filters EIP
pattern) by default, when doing directly routing from -> to.

There is a FAQ entry here:
http://activemq.apache.org/camel/how-to-send-the-same-message-to-multiple-endpoints.html

Multicast = same message being sent to all destinations
Pipeline = like a chain (pipes and filters). 
 
/Claus, a Camel rider



Louis Polycarpou wrote:
> 
> Thanks. I'll try that.  The multicast fluent builder example 
> http://activemq.apache.org/camel/multicast.html here   doesn't use end:
> 
> from("direct:a").multicast().to("direct:x", "direct:y", "direct:z");
> 
> What's the difference between:
> 
>  multicast().to("direct:x", "direct:y", "direct:z").end(); 
> 
> and
> 
>  to("direct:x", "direct:y", "direct:z");
> 
> Thanks.
> 
> Hadrian Zbarcea wrote:
>> 
>> Hi,
>> 
>> Did you try end() to terminate the multicast?  As in:
>> from(uri).
>>    choice().
>>      when(expr).multicast().to(uris).end().
>>      otherwise().to(pojo);
>> 
>> Cheers
>> Hadrian
>> 
>> 
>> On Aug 6, 2008, at 8:28 PM, Louis Polycarpou wrote:
>> 
>>>
>>>
>>>
>>> Louis Polycarpou wrote:
>>>>
>>>> I'm trying to broadcast a feed to multiple endpoints but with
>>>> content-based selection. I assume I need to use multicast, however, I
>>>> can't achieve conditional multicast based on content selection  
>>>> since I
>>>> can't use an otherwise() method after using  
>>>> multicast().to("endpoint1",
>>>> "endpoint2")
>>>>
>>>> Furthermore, the to() method supports a list of endpoints without
>>>> requiring a multicast first so what is the difference between that  
>>>> and a
>>>> multicast().to(...)?
>>>>
>>>> feed in -> multicast to two outputs
>>>>
>>>> To recap with code:
>>>>
>>>> 1) I can't use otherwise after a multicast...
>>>>
>>>>        from(cnn).
>>>>                choice().
>>>>                when(xpath(filter)).multicast().to(im, archive); // I
>>>> can't now use otherwise()...
>>>>
>>>> 2) Do I really need multicast or can I just do the following...?
>>>>
>>>>        from(cnn).
>>>>                choice().
>>>>                when(xpath(filter)).to(im, archive).
>>>>                otherwise().to(myPojo);
>>>>
>>>>
>>>
>>> One way I've worked around this is to inverse the filter and do the
>>> multicast in the otherwise() part but clearly this doesn't answer my
>>> original question:
>>>
>>> from(cnn).
>>>                choice().
>>>                when(xpath(filter)).to(stdout).
>>>                otherwise().multicast().to(im, archive);
>>>
>>> -- 
>>> View this message in context:
>>> http://www.nabble.com/Multicast-with-choice-tp18861976s22882p18862033.html
>>> Sent from the Camel - Users mailing list archive at Nabble.com.
>>>
>> 
>> 
>> 
> 
> 

-- 
View this message in context: http://www.nabble.com/Multicast-with-choice-tp18861976s22882p20278430.html
Sent from the Camel - Users mailing list archive at Nabble.com.


Re: Multicast with choice

Posted by Hadrian Zbarcea <hz...@gmail.com>.
Louis, actually, there is no difference, end() is implicit.  There  
would be a difference if you had something like:

multicast 
().to("direct:x").to("direct:y").to("direct:z").end().to("direct:a")

Without the end() they'd be all done in parallel, with end()  
"direct:a" is done after all the other exchanges finish.  The reason  
end() is optional is because Blocks were added a bit later (in 1.3  
iirc) and we wanted to keep backwards compatibility, i.e. not make  
end() mandatory and have existing users update their routes.

My $0.02,
Hadrian


On Nov 1, 2008, at 4:41 AM, davsclaus wrote:

>
> Hi
>
> A bit late with the answer, but Camel uses Pipeline (pipes and  
> filters EIP
> pattern) by default, when doing directly routing from -> to.
>
> There is a FAQ entry here:
> http://activemq.apache.org/camel/how-to-send-the-same-message-to-multiple-endpoints.html
>
> Multicast = same message being sent to all destinations
> Pipeline = like a chain (pipes and filters).
>
> /Claus, a Camel rider
>
>
>
> Louis Polycarpou wrote:
>>
>> Thanks. I'll try that.  The multicast fluent builder example
>> http://activemq.apache.org/camel/multicast.html here   doesn't use  
>> end:
>>
>> from("direct:a").multicast().to("direct:x", "direct:y", "direct:z");
>>
>> What's the difference between:
>>
>> multicast().to("direct:x", "direct:y", "direct:z").end();
>>
>> and
>>
>> to("direct:x", "direct:y", "direct:z");
>>
>> Thanks.
>>
>> Hadrian Zbarcea wrote:
>>>
>>> Hi,
>>>
>>> Did you try end() to terminate the multicast?  As in:
>>> from(uri).
>>>   choice().
>>>     when(expr).multicast().to(uris).end().
>>>     otherwise().to(pojo);
>>>
>>> Cheers
>>> Hadrian
>>>
>>>
>>> On Aug 6, 2008, at 8:28 PM, Louis Polycarpou wrote:
>>>
>>>>
>>>>
>>>>
>>>> Louis Polycarpou wrote:
>>>>>
>>>>> I'm trying to broadcast a feed to multiple endpoints but with
>>>>> content-based selection. I assume I need to use multicast,  
>>>>> however, I
>>>>> can't achieve conditional multicast based on content selection
>>>>> since I
>>>>> can't use an otherwise() method after using
>>>>> multicast().to("endpoint1",
>>>>> "endpoint2")
>>>>>
>>>>> Furthermore, the to() method supports a list of endpoints without
>>>>> requiring a multicast first so what is the difference between that
>>>>> and a
>>>>> multicast().to(...)?
>>>>>
>>>>> feed in -> multicast to two outputs
>>>>>
>>>>> To recap with code:
>>>>>
>>>>> 1) I can't use otherwise after a multicast...
>>>>>
>>>>>       from(cnn).
>>>>>               choice().
>>>>>               when(xpath(filter)).multicast().to(im,  
>>>>> archive); // I
>>>>> can't now use otherwise()...
>>>>>
>>>>> 2) Do I really need multicast or can I just do the following...?
>>>>>
>>>>>       from(cnn).
>>>>>               choice().
>>>>>               when(xpath(filter)).to(im, archive).
>>>>>               otherwise().to(myPojo);
>>>>>
>>>>>
>>>>
>>>> One way I've worked around this is to inverse the filter and do the
>>>> multicast in the otherwise() part but clearly this doesn't answer  
>>>> my
>>>> original question:
>>>>
>>>> from(cnn).
>>>>               choice().
>>>>               when(xpath(filter)).to(stdout).
>>>>               otherwise().multicast().to(im, archive);
>>>>
>>>> -- 
>>>> View this message in context:
>>>> http://www.nabble.com/Multicast-with-choice-tp18861976s22882p18862033.html
>>>> Sent from the Camel - Users mailing list archive at Nabble.com.
>>>>
>>>
>>>
>>>
>>
>>
>
> -- 
> View this message in context: http://www.nabble.com/Multicast-with-choice-tp18861976s22882p20278430.html
> Sent from the Camel - Users mailing list archive at Nabble.com.
>