BPEL - Append multiple elements to a list

Problem: I had a list of XML elements like so:

<Messages> <Message Area="RES" Code="Code1"/> <Message Area="RES" Code="Code2"/> <Message Area="RES" Code="Code3"/> </Message>

This is the XSD:

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://danytests.com/soa/bpel-append" targetNamespace="http://danytests.com/soa/bpel-append" elementFormDefault="qualified"> <xsd:element name="Messages" type="MessagesType"> <xsd:annotation> <xsd:documentation>A sample element</xsd:documentation> </xsd:annotation> </xsd:element> <xsd:complexType name="MessagesType"> <xsd:sequence> <xsd:element name="Message" maxOccurs="unbounded"> <xsd:complexType> <xsd:attribute name="Area" type="xsd:string"/> <xsd:attribute name="Code" type="xsd:string"/> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:schema>

What I needed to do was append more items to the already existing list without affecting the ones that were already in there.

At first what I was doing was adding the new items to add to a BPEL variable ($varMessages) that was also of MessagesType. Then, with another variable ($messageCount), I would assign the count of Messages/Message PLUS 1 to it (so, in this case, it would be 4). In a foreach loop, starting with $messageCount, I would do a simple Copy to Messages/Message[$messageCount] and setting the insertMissingToData flag. This, however, isn't really the right way to go about this.

Solution: Use the BPEL Append action instead of the Copy action.

To accomplish this, I would still have the $varMessages variable assigned with the new items to add, but instead my BPEL assign activity would look like this:

<assign name="appendMessages"> <extensionAssignOperation> <bpelx:append> <bpelx:from>$varMessages/ns1:Message</bpelx:from> <bpelx:to>$outputVariable.payload</bpelx:to> </bpelx:append> </extensionAssignOperation> </assign>

That is, I'd assign the Messages from $varMessages to the final list ($outputVariable) in the Messages complexType.

The results were as expected while looking at it in the audit trail. First I'd assign a Message element to the $outputVariable:

Then I'd add elements to $varMessages:

Finally, after the append action, the output variable's final list would look like this:

Neat!