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From Jon Anstey <jans...@gmail.com>
Subject Re: Newbie Question - Content Filtering
Date Thu, 19 Feb 2009 19:03:19 GMT
Try filtering using a custom bean expression instead. Something like this

from("jms:queue:testQueue").filter().method("myTestDBFilter",
"hasNewContent").to("jms:queue:otherTestQueue");

Where your bean would be something like this

    class TestDBFilter {
        public static boolean hasNewContent(@Body YourCustomObject body) {
            // 1. extracts the content from the body
            // 2. performs the DB lookup
            // 3. returns true if it has new content
        }
    }

Also your message will be discarded if you don't have any other steps in
your route so your other requirement is good too.

On Thu, Feb 19, 2009 at 3:20 PM, triswork <tristan.koen@gmail.com> wrote:

>
> I am new to Camel and am trying to migrate some code I wrote using the
> javax.jms classes across to Camel. I have a specific problem and I am not
> too sure if my approach is the optimal solution. I would really appreciate
> some feedback from the veterans on this list.
>
> Basically, my application performs the following:
> 1) A consumer retrieves a Serialized Java object from a Queue.
> 2) The contents of a data field within the object are matched against a set
> of database records.
> 3) If the content corresponds to an existing record, the database record is
> updated and the object is discarded.
> 4) If the content is new, it is written to the database, some of the object
> data is updated and it is routed to another JMS queue for further
> processing.
>
> My approach in Camel has been to create a RouteBuilder that works something
> like this
> from("jms:queue:testQueue")
>  .process(new TestDBFilter())
>
>
> .filter(header("newContent").isEqualTo("true")).to("jms:queue:otherTestQueue");
>
> My TestDBFilter class basically
>  - extracts the content from the message using getIn();
>  - Performs the DB lookup
>  - Updates the message headers on getOut()
>
> Is this a valid approach? It seems a bit contrived to me that I have to put
> a filter on a header field after my processor executes. Two specific
> questions:
> 1) Is there a simpler/more efficient way to do this?
> 2) Do I have to do anything special to the message to get rid of it (in
> cases where the DB record already exists). Or will it just be discarded
> when
> it fails on my filter predicate?
>
> Thanks in advance for any feedback/advice
>
> Tristan
> --
> View this message in context:
> http://www.nabble.com/Newbie-Question---Content-Filtering-tp22107198s22882p22107198.html
> Sent from the Camel - Users mailing list archive at Nabble.com.
>
>


-- 
Cheers,
Jon

http://janstey.blogspot.com/

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