How implement customed transaction section in camel?

[ext2 <xu...@tongtech.com>]

Hi:
	Camel 's transaction-policy is applied for all processors in the
route;  but how to use this features to implement a customized transaction
section in camel? Etc: if I could assign a transaction-policy to a single
pipe-line processor(not the whole route), I could define custom transaction
section easily;

To illustrate this usage I give a sample , and I want to know is there
a-better solution to  use camel;

For example: A application which read message from jms and, save the message
to 2 different database table(A, B). This application asks for this
transaction features: 

Two  database table must keep in a same transaction: one failed another
rollback; 

Jms  must take part in seperate transaction, that's to say if both database
success, the jms will commit; if one database failed, I will log the jms
message in a storage, and jms will commit;  But if logging failed, the jms
will rollback;
 
And how to full-fill this transaction features using camel? 
Must I separate the complete route into different route piece just for
transaction support? 
Could camel support the define a transaction range (but not a
transaction-policy)?

Even I separate the complete route into different route just for transaction
support, it still has a difficult: how to declared a new transaction for a
processing route( in this sample , I need to declare a new transaction for
table-A and table-B processors);   if I declared a required-new-transaction
policy, all the processor in route act in a separate transaction; and it
cannot full-fill such demand: table A and table B act in a transaction;
To resolve this problem , I must introduce another route just act as a
bridge for the new-tx-range);following is a solution use camel's current
transaction policy to  this example, but it's hard to understand:

routeA: (jms)
	(from-jms)-->(required-tx-policy)-->doTry-->(to
direct:new-tx-op)-->(docatch)-->(log);

routeB:(this is the hardest part for usage)
(from direct:new-tx-op)-->new-tx -policy-->(to direct:db-op)

Route C:
(from direct:db-op)-->(required-tx-policy)-->(table A save)-->(table B save)

So does camel support a feature to define transaction range? So the route
will looks like

(from jms)-->pipeline(required-tx) -->[dotry-->pipeline(new-tx)-->[(table
A)-->(table B)]-->docatch-->log];

If camel could assign a transaction-policy to single pipe-line process ,
this feature could be achieved easily;

Re: How implement customed transaction section in camel?

[Claus Ibsen <cl...@gmail.com>]

Hi

This requires Camel 2.2 onwards.
And check out chapter 9 in the book as it covers using multiple TX demarcations.



On Wed, Apr 21, 2010 at 4:41 PM, ext2 <xu...@tongtech.com> wrote:
>
> Hi:
>        Camel 's transaction-policy is applied for all processors in the
> route;  but how to use this features to implement a customized transaction
> section in camel? Etc: if I could assign a transaction-policy to a single
> pipe-line processor(not the whole route), I could define custom transaction
> section easily;
>
> To illustrate this usage I give a sample , and I want to know is there
> a-better solution to  use camel;
>
> For example: A application which read message from jms and, save the message
> to 2 different database table(A, B). This application asks for this
> transaction features:
>
> Two  database table must keep in a same transaction: one failed another
> rollback;
>
> Jms  must take part in seperate transaction, that's to say if both database
> success, the jms will commit; if one database failed, I will log the jms
> message in a storage, and jms will commit;  But if logging failed, the jms
> will rollback;
>
> And how to full-fill this transaction features using camel?
> Must I separate the complete route into different route piece just for
> transaction support?
> Could camel support the define a transaction range (but not a
> transaction-policy)?
>
> Even I separate the complete route into different route just for transaction
> support, it still has a difficult: how to declared a new transaction for a
> processing route( in this sample , I need to declare a new transaction for
> table-A and table-B processors);   if I declared a required-new-transaction
> policy, all the processor in route act in a separate transaction; and it
> cannot full-fill such demand: table A and table B act in a transaction;
> To resolve this problem , I must introduce another route just act as a
> bridge for the new-tx-range);following is a solution use camel's current
> transaction policy to  this example, but it's hard to understand:
>
> routeA: (jms)
>        (from-jms)-->(required-tx-policy)-->doTry-->(to
> direct:new-tx-op)-->(docatch)-->(log);
>
> routeB:(this is the hardest part for usage)
> (from direct:new-tx-op)-->new-tx -policy-->(to direct:db-op)
>
> Route C:
> (from direct:db-op)-->(required-tx-policy)-->(table A save)-->(table B save)
>
> So does camel support a feature to define transaction range? So the route
> will looks like
>
> (from jms)-->pipeline(required-tx) -->[dotry-->pipeline(new-tx)-->[(table
> A)-->(table B)]-->docatch-->log];
>
> If camel could assign a transaction-policy to single pipe-line process ,
> this feature could be achieved easily;
>
>
>



-- 
Claus Ibsen
Apache Camel Committer

Author of Camel in Action: http://www.manning.com/ibsen/
Open Source Integration: http://fusesource.com
Blog: http://davsclaus.blogspot.com/
Twitter: http://twitter.com/davsclaus