Scope Activity in BPEL
This activity consists of a collection
of nested activities that can have their own local variables, fault handlers,
compensation handlers, and so on. A scope activity is analogous to a { } block
in a programming language.
Each scope has a primary activity that
defines its behavior. The primary activity can be a complex structured
activity, with many nested activities within it to arbitrary depth. The scope
is shared by all the nested activities.
Figure A-33
shows the Scope dialog in BPEL 1.1. Define appropriate activities inside the
scope activity.
In BPEL 2.0, the Scope dialog includes a
Documentation tab and does not include a Skip Condition
tab.
Fault handling is associated with a
scope activity. The goal is to undo the incomplete and unsuccessful work of a
scope activity in which a fault has occurred. You define catch activities in a
scope activity to create a set of custom fault-handling activities. Each catch
activity is defined to intercept a specific type of fault.
Figure A-34
shows the Add Catch icon inside a scope activity.
Figure A-35
shows the catch activity area that appears when you click the Add Catch
icon.
Within the area defined as Drop Activity Here, you drag additional
activities to create fault handling logic to catch and manage exceptions.
For example, a client provides a social
security number to a Credit Rating service when applying for a loan. This
number is used to perform a credit check. If a bad credit history is identified
or the social security number is identified as invalid, an assign activity
inside the catch activity notifies the client of the loan offer rejection. The
entire loan application process is terminated with a terminate activity.
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