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From Claus Ibsen <claus.ib...@gmail.com>
Subject Re: URI references to Objects in the Registry
Date Thu, 14 Feb 2013 14:30:23 GMT
Hi Scott

On Thu, Feb 14, 2013 at 1:38 PM, Scott Cranton <scott@cranton.com> wrote:
> I've just noticed the reference syntax that some components use, but
> its not clear to me exactly how it works, and more importantly how new
> components are supposed to use it correctly... I don't see any
> documentation on it, and I've only found some mentions of it in the
> JIRA where it was created and in the camel code itself.
>
> Sorry if I missed an earlier thread on this, but I couldn't find it...
>

Yeah Camel has many many pages. Its documented here:
http://camel.apache.org/configuring-camel.html

At the section .. Referring beans from Endpoint URIs.

Maybe we should add a FAQ as well?
And if you have suggestions for other places in the docs to add
reference / note about this, then feel free to change the docs /
suggest.


> It looks like Camel will resolve "#name" values for endpoint uri
> properties to the a Registry id instance.
>
> <bean id="bar" class="some.java.clazz"/>
>
> <to uri="someEndpoint:foo?objectProperty=#bar" />
>
> The above syntax will set the Component's configuration, internally
> resolving "#bar" to the bean instance from the Camel Registry...
>
> setObjectProperty(some.java.clazz value)
>

Yes the # is a reference lookup in the registry and will match with
the bean type as well.


> I'm also seeing some cases where it looks like there is magic if you
> suffix a property name with "Ref" that will do the same thing...
>

There is no magic. There is an option with that name.

> <to uri="someEndpoint:foo?objectPropertyRef=bar"/>
>

They are typically from the earlier days of Camel where we did not
have the # lookup.
Then we needed to have 2 options for the same thing. So you can
configure it as a java type.
And as well sometimes to refer to the registry. And hence we had the
xxx and xxxRef options.



> I assume its the same base Component and Endpoint code that's
> resolving this, but I can't find it (yet)...
>
> The confusing bit is that some Processors and Component doc use
> different conventions...
>
> It looks like an effort was made to normalize this convention around
> version 2.2 or 2.3 timeframe, hence some of the inconsistencies... My
> question is what is the current "best practice" and/or what would we
> like the convention, both in code and in doc, for version 3
>
> BTW: I like the reference syntax, but it did take me a bit to figure
> out "is this a Spring thing" or "Camel magic", and "is it just '#name'
> that is magic and/or is suffixing with Ref magic", etc.
>
> Thanks,
> Scott

You can check the source code for DefaultComponent as thats the one
that usually handles this.

We have some helper classes that does all the hard work

  EndpointHelper.setReferenceProperties(getCamelContext(), bean, parameters);
        EndpointHelper.setProperties(getCamelContext(), bean, parameters);



-- 
Claus Ibsen
-----------------
Red Hat, Inc.
FuseSource is now part of Red Hat
Email: cibsen@redhat.com
Web: http://fusesource.com
Twitter: davsclaus
Blog: http://davsclaus.com
Author of Camel in Action: http://www.manning.com/ibsen

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