[jboss-user] [JBoss jBPM] - Re: BPEL workflow - who to determine whats the next step?

alex.guizar@jboss.com do-not-reply at jboss.com
Fri Sep 15 00:29:51 EDT 2006


TNT,

You are thinking in terms of the jBPM object model. In BPEL the concept of process instance is rather abstract and the token does not exist.

Consider the ATM example. The process instance sits waiting for an ATM to send a log-on message. This might take an arbitrarily long time, hours, perhaps days. During this time the process is stopped and the process objects are stored in the database. To resume the process, you send a log-on message to the front end web service and provide the ticket number assigned to the ATM.

Internally, the BPEL runtime will take the ticket number, "correlate" it to a dormant token, load it from the database and signal it for you. There are some other actions the engine must perform, such as assigning the message data to the process variables, ensuring the correlation constraint and registering an outstanding request in case the request expects a response.

I cannot think of a reason why you would want to perform these actions yourself, so why do you need direct access to the token? Take into account that one of the selling points of BPEL is its being a standard. If you dive into a particular implementation, you won't be able to switch to a different implementation easily (should you ever want to :-)

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