1. Developing SOA Applications with Oracle SOA Suite
  2. Using the BPEL Process Service Component
  3. Manipulating XML Data in a BPEL Process
  4. Manipulating XML Data Sequences That Resemble Arrays
  5. How to Dynamically Index by Applying a Trailing XPath to an Expression
  6. Generating Functionality Equivalent to an Array of an Empty Element

Generating Functionality Equivalent to an Array of an Empty Element

The genEmptyElem function generates functionality equivalent to an array of an empty element to an XML structure. This function takes the following arguments: 

genEmptyElem('ElemQName',int?, 'TypeQName'?, boolean?)

Note the following issues:

  • The first argument specifies the QName of the empty elements.

  • The optional second integer argument specifies the number of empty elements. If missing, the default size is 1.

  • The third optional argument specifies the QName, which is the xsi:type of the generated empty name. This xsi:type pattern matches the SOAPENC:Array. If it is missing or is an empty string, the xsi:type attribute is not generated.

  • The fourth optional boolean argument specifies whether the generated empty elements are XSI - nil, provided the element is XSD-nillable. The default value is false. If missing or false, xsi:nil is not generated.

The following example shows an append statement initializing a purchase order (PO) document with 10 empty <lineItem> elements under po: 

<bpelx:assign> 
    <bpelx:append>
        <bpelx:from expression="ora:genEmptyElem('p:lineItem',10)" />
        <bpelx:to variable="poVar" query="/p:po" /> 
    </bpelx:append>
</bpelx:assign>

The genEmptyElem function in the previous example can be replaced with an embedded XQuery expression, as shown in the following example: 

ora:genEmptyElem('p:lineItem',10) 
== for $i in (1 to 10) return <p:lineItem />

The empty elements generated by this function are typically invalid XML data. You perform further data initialization after the empty elements are created. Using the same example above, you can perform the following:

  • Add attribute and child elements to those empty lineItem elements.

  • Perform copy operations to replace the empty elements. For example, copy from a web service result to an individual entry in this equivalent array under a flowN activity.