XMLChoice

Map a BDL Record to an XML Schema choice structure. The choice of the record's member is performed at runtime, and changes dynamically depending on a mandatory member. This specific member must be of type SMALLINT or INTEGER, and have an XMLSelector attribute set.

The XMLChoice attribute also supports a "nested" value that removes the surrounding XML tag.
  1. The compiler indexes all elements of a record with an XMLChoice attribute but the Genero Web Server (GWS) only serializes the element set by the selector value as the member to be serialized. If the selected element has no XMLName attribute, it will use the Genero BDL name as the XML tag.
  2. Nested choice records cannot be defined as main variables; there must always be a surrounding variable.

Example 1: Record with XMLChoice

In the sample record, note the index value of the record element shown in the comment with the hash symbol ( # ).

DEFINE mychoice RECORD ATTRIBUTES(XMLChoice,XMLName="Root")
  val1  INTEGER   ATTRIBUTES(XMLName="Val1"),              #1 
  val2  FLOAT     ATTRIBUTES(XMLAttribute,XMLName="Val2"), #2 
  sel   SMALLINT  ATTRIBUTES(XMLSelector),                 #3 selector node
  val3  STRING    ATTRIBUTES(XMLName="Val3")               #4 
END RECORD

Case where "sel" value is set to 4 (LET mychoice.sel = 4). The XML output is:

<Root Val2="25.8">
  <Val3>Hello world</Val3>
</Root>

Case where "sel" value is set to 1 (LET mychoice.sel = 1). The XML output is:

<Root Val2="25.8">
  <Val1>148</Val1>
</Root>

Example 2: Record with nested XMLChoice record

In this example, the XMLChoice attribute is set on the choice record, which is a record nested in the myvar record. It has a selector node (nestedSel), which is set with the XMLSelector attribute. The index value of the nested record elements is shown in the comment with the hash symbol ( # ) for clarity. The selector node is also part of the index. 
DEFINE myVar RECORD ATTRIBUTES(XMLName="Root")
  val1  INTEGER   ATTRIBUTES(XMLName="Val1"),               
  val2  FLOAT     ATTRIBUTES(XMLAttribute,XMLName="Val2"),  
  choice RECORD   ATTRIBUTES(XMLChoice="nested")
    choice1   INTEGER   ATTRIBUTES(XMLName="ChoiceOne"),    #1 
    choice2   FLOAT     ATTRIBUTES(XMLName="ChoiceTwo"),    #2 
    nestedSel SMALLINT  ATTRIBUTES(XMLSelector)             #3 selector node
  END RECORD,
  val3  STRING    ATTRIBUTES(XMLName="Val3")
END RECORD
Case where "nestedSel" value is set to 1 (LET myVar.choice.nestedSel = 1). The XML output is:
<Root Val2="25.8">
  <Val1>148</Val1>
  <ChoiceOne>6584</ChoiceOne>
  <Val3>Hello world</Val3>
</Root>
Case where "nestedSel" value is set to 2 (LET myVar.choice.nestedSel = 2). The XML output is: 
<Root Val2="25.8">
  <Val1>148</Val1>
  <ChoiceTwo>85.8</ChoiceTwo>
  <Val3>Hello world</Val3>
</Root>

Example 3: Using XMLChoice="nested" for substitutionGroup

In this example the XMLChoice="nested" option produces an XML output supporting a substitutionGroup. If you have a WSDL containing a substitutionGroup as in the following XSD schema example, the "name" element can be represented as a simple string type (simple-name) or as a more complex type (full-name). 
<xs:element name="name" />
<xs:element name="simple-name" type="xs:string" substitutionGroup="name" />
<xs:element name="full-name" substitutionGroup="name">
  <xs:complexType>
    <xs:all>
      <xs:element name="first" type="xs:string" minOccurs="0"/>
      <xs:element name="middle" type="xs:string" minOccurs="0"/>
      <xs:element name="last" type="xs:string"/>
    </xs:all>
  </xs:complexType>
</xs:element>

<xs:element name="Identity"/>
  <xs:sequence>
    <xs:element ref="name"/>
  </xs:sequence>
</xs:element>
In the next example, a BDL RECORD (Identity) is defined to specify the XML representation for the schema:
DEFINE Identity RECORD ATTRIBUTE(XMLSequence,XMLName="Identity")
         name RECORD ATTRIBUTE(XMLChoice="nested")
           _SELECTOR_ SMALLINT ATTRIBUTE(XMLSelector),
           name STRING,                                             #1
           simple_name STRING ATTRIBUTE(XMLName="simple-name"),     #2
           full_name RECORD ATTRIBUTE(XMLAll,XMLName="full-name")   #3
             first STRING ATTRIBUTE(XMLOptional),
             middle STRING ATTRIBUTE(XMLOptional),
             last STRING 
           END RECORD
         END RECORD
       END RECORD
Where:
  • The name element is the substitutionGroup tag. The XMLChoice="nested" attribute is set on this variable. This element is not serialized in XML.
  • The selector node (_SELECTOR_) is set with the XMLSelector attribute.
  • name is a STRING.
  • simple-name is a STRING set with an XMLName attribute.
  • full-name is a RECORD set with an XMLAll and XMLName attribute. It has two optional STRING elements, first and middle set with XMLOptional attributes. Its last element is a STRING.

You can choose at runtime one of the available options for name: name, simple-name, or full-name. You set the selector node to the index value of the record element, for example LET Identity._SELECTOR_= 2. The index value of record elements is shown in the comment with the hash symbol ( # ) for clarity.

This is an example of the XML output when the _SELECTOR_ value is 3:
<Identity>
  <full-name>
     <first>John</first>
     <last>Smith</last>
  </full-name>
</Identity>
This is an example of the XML output when the _SELECTOR_ value is 2:
<Identity>
  <simple-name>John Smith</simple-name>
</Identity>