Information Technology Reference
In-Depth Information
Configuring sequence flow elements
Sequence flows are the elements used to connect the Activities, Events, and Gateways in
our processes. Only the following two sequence flows' properties have an impact on the
jBPM6 engine:
Property
Description
For sequence flow elements coming from a diverging inclusive gateway or a diverging exclusive gateway, this property defines the
condition that needs to be evaluated. Depending on its result, the execution will either continue through this flow or not. Inside the
condition expression code, we can access all of the variables defined in our process.
Condition
expression
The process designer provides a guided editor to write conditions based on process instance variable evaluations, but if you wish
to write something more complex, it has a
Script
tab where you can write more complex scripts in a sentence of the following
form:
return <expression resolving to Boolean>;
Three different languages are allowed in the condition expression property: Java, MVEL, and Drools. We can use this property to
specify the language we want to use.
Condition
expression
language
If Java or MVEL is selected, the condition expression must be valid Java code or MVEL script, respectively. Other than the pro-
cess variables, a special variable with the name
kcontext
can be used to get extra information about the process instance.
If we use Drools as the condition expression language, the syntax we have to use in the condition expression is Drools' DRL.
Basically, we have to define a constraint using DRL that will evaluate to true or false.
As we are not using any diverging inclusive or exclusive gateway in the process that we are
designing, there is no need to modify either of these properties in any of the sequence flows
we have.
