I am not sure if I really understand the concept behind this. Is there any text 
about the general ideas behind these changes?

If I got this right, you propose that endpoints declare a kind of data type 
that can be verified as input and output types (like a specific XML schema) and 
the camel route will automatically validate this constraint. Did I get this 

Concerning this payload classification we have actually three kinds of 
endpoints in camel:
1. Endpoints that do not care about data content at all (e.g. a file)
2. Endpoints that do care about data content, however the specific content type 
definition may be part of the endpoint configuration. An example for this might 
be a CXF web service endpoint with a WSDL. The endpoint as such only demands 
that the payload is some kind of XML but the WSDL may (or may not e.g. if the 
message definition is xsd:any) put some additional restriction on the payload 
3. Endpoints that enforce some kind of (usually technical) format on the 
endpoint (data types are usually of that kind. If you are trying a zipfile 
unmarshal, you'd better have a zip file as a payload...).
Are you focusing any of these kinds of endpoint types or are you just focusing 
some special processors that operate on very specific data?

Best regards

-----Original Message-----
From: Tomohisa Igarashi [mailto:tm.igara...@gmail.com] 
Sent: Montag, 17. Oktober 2016 04:36
To: dev@camel.apache.org
Subject: Re: Adding type awareness in Camel route


I'd like to resume the discussion about this. I still think 3.0 would be the 
best target to get this feature fully supported, but to achieve it in better 
shape, I'd like to have it in 2.19 as well as an experimental, ask feedback and 
then reflect those for 3.0 full support. Fortunately this is purely an addition 
to existing features, i.e. is not breaking any existing API. What do you think?


On 09/17/2016 10:20 PM, Tomohisa Igarashi wrote:
> Hi Claus,
> Thanks for the reply. Sure that's fine, I agree 3.0 would be better to be 
> targeted than 2.x as this introduces some schema updates.
> Including this one, I'm always looking for the chance to make any 
> contribution to Camel. If there's anything I can help please let me know.
> Thanks,
> Tomo
> On 09/17/2016 06:33 PM, Claus Ibsen wrote:
>> Hey
>> Can we take this discussion post Camel 2.18 release.
>> We are working on the last details to get it ready, and its our main
>> focus to get this new release out.
>> After this release we will pickup talks about the next releases
>> whether that is 2.19 or 3.0, and for the latter what the broad goals
>> of that is. What you talk about seems more of a 3.0 candidate to me,
>> than on 2.x.
>> On Fri, Sep 16, 2016 at 6:50 AM, Tomohisa Igarashi
>> <tm.igara...@gmail.com> wrote:
>>> Hi Camel developers,
>>> I'd like to propose an enhancement on handling data types of Camel message
>>> contents. To start a smooth discussion I implemented the idea first:
>>> https://github.com/igarashitm/camel/tree/contract-based-type-awareness
>>> And these testcases demonstrates the declarative transformer usage according
>>> to the declared data types:
>>> [Java DSL]
>>> https://github.com/igarashitm/camel/commit/498c27d2ba99b04bbe7b90a93329d42b7c718a29#diff-c14a7e8e88a6e41492946e1537bfb1cf
>>> [Spring DSL]
>>> https://github.com/igarashitm/camel/commit/498c27d2ba99b04bbe7b90a93329d42b7c718a29#diff-b2506c84ddde91438fc6374039e21534
>>> This adds input/output content type declaration on from and all other
>>> processors. It also introduces well-known Exchange properties, INPUT_TYPE
>>> and OUTPUT_TYPE which are used to specify the current message content type.
>>> The data type is URN like string starts with scheme, like
>>> java:org.example.ItemA or xml:{org.example.xml}ItemA.
>>> If the content type is declared via inputType/outputType/contract, the
>>> ContractProcessor wraps the actual processor and process
>>> transformation/validation according to the type, say if INPUT_TYPE exchange
>>> property has xml:{org.example.xml}ItemA and the declared inputType is
>>> xml:{org.example.xml}ItemB, then it transforms xml:{org.example.xml}ItemA
>>> content into xml:{org.example.xml}ItemB. The <transformers> element which is
>>> introduced right under the <camelContext> is the one to declare the mappings
>>> between transformer implementation and those from/to data type. I
>>> implemented only transformer first, but validator would be brought in in a
>>> same way. This way allows users to make data types visible in the route
>>> definition and keep the transformation/validation apart from route
>>> definition itself.
>>> The most important thing is that the ContractProcessor is involved only when
>>> content type is explicitly declared in a route definition, so that it never
>>> breaks existing camel routes. Ofcourse programatic
>>> transformations/validations we're doing today are still fully available.
>>> It's purely an addition to the existing camel features.
>>> Any thoughts? Does it sound acceptable to get merged into camel? ANY
>>> feedback would be really appreciated!
>>> Thanks,
>>> Tomo

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