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From lassesvestergaard <>
Subject Conceptual understanding of altering routes runtime
Date Wed, 04 Sep 2013 16:53:15 GMT
Hi all.

This is a spinoff of a previous post:

I decided to start a new thread, because I think this question is of a more
general character.

First of all, I ran into a problem regarding how to update a camel route
runtime. My concrete problem is that I can't figure out how to update a sql
query runtime. If I, for instance, want to have a query that fetches the
first 3000 records of a table, on the first cycle of the camel route (let's
say I use a timer to "fire" the route). In the next cycle, I want to fetch
from record 3001 to 6000. I simply can't get my head around this problem,
which is extremely simple in regular java. My conclusion from this is, that
I have some fundamental misconceptions of what Apache camel is, and therefor
I want to use this thread to discuss runtime altering of routes.

For starters: As I understand, an Exchange is a entity that only exists
within a single cycle of a route. This means that I can't use the Exchange
object to save variables that I can use in the next cycle of the route. This
further means that I can't use Exchange to alter configurations of a
component - ex. I can't use it for giving the timer component a different
period and I can't use it for altering variables in a sql query.

Besides this, it seems that you can only write your route once, and the
first time it's run, all component configurations are set - they cannot be
altered from within the route it self. In my specific case, I have tried to
put java variables into my sql query (having them assigned as class scoped
attributes). In my route I have a Processor (see referenced thread at the
top), and in that I have altered the java attributes. This seems to work
fine, but the sql query doesn't get updated with the new value of my java

Furthermore, I haven't been able to find any good examples, that show how to
alter the route configurations runtime (actually the configurations of each
component in a route).

Since I can't Google the problem away, I conclude that I have issues on the
conceptual understanding of Camel. So, could someone please clarify how to
understand runtime alterings of routes, and it would be even better if you
have some concrete coding examples.

I have chosen to use the java DSL approach instead of Spring.

Best regards

Lasse Vestergaard

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