[ODE-371] Auto Complete Copy Destination (L-Value)

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2
• Fix Version/s: 1.3.2
• Environment: platform-independent
• Assignee: Karthick Sankarachary
• Reporter: Karthick Sankarachary
• Created: 12/Sep/08 20:59
• Updated: 24/Apr/09 00:54
• Resolved: 04/Nov/08 20:24

Description

A lot of times, users expect the <copy> operation in a WS-BPEL assign activity to behave such that the path specified by the destination ("to-spec") is automatically created, if it doesn't already exist. By default, if the to-spec used within a <copy> operation does not select exactly one XML information item during execution, then the standard fault bpel:selectionFailure is thrown (as mandated by the spec).

To override this default behavior, we introduce a insertMissingToData attribute in the <copy> operation, which if it is set to "yes", will instruct the runtime to complete the (XPath) L-value specified by the to-spec, if no items were selected. For the sake of simplicity, we will complete the to-spec if and only if:
a) It's a path expression whose steps are separated by "/", and
b) Its steps have an axis, which is either "child" or "attribute", and
c) Its steps have no following predicates, and
d) Its steps test the name of a node, without the use of wildcards.

Formally, the grammar of the to-spec, for which auto-complete is enabled, may be defined in terms of these productions:
PathExpr ::= ("/" RelativePathExpr?) | RelativePathExpr
RelativePathExpr ::= ForwardStep (("/" ) ForwardStep)*
ForwardStep ::= (ForwardAxis QName) | AbbrevForwardStep
AbbrevForwardStep ::= "@"? QName
ForwardAxis ::= ("child" "::") | ("attribute" "::")

The example below illustrates the use of the insertMissingToData attribute. Let's say that the variable "response" is uninitialized. In that case, the first <copy> operation will fail, whereas the second one will succeed.

<copy>
<from>$request.requestMessageData/typeIndicators/types:indicatorTwo</from>
<to>$response/typeIndicators/types:indicatorTwo</to>
</copy>

<copy insertMissingToData="yes">
<from>$request.requestMessageData/typeIndicators/types:indicatorTwo</from>
<to>$response/typeIndicators/child::types:indicatorTwo</to>
</copy>

Best Regards,
Karthick Sankarachary