Support for <xsd:choice>

An <xsd:choice> element indicates that only one of the options in the element can be used. The CICS® assistants provide varying degrees of support for <xsd:choice> elements at the various mapping levels.

Support for <xsd:choice> at mapping level 2.2 and higher

At mapping level 2.2 and higher, DFHWS2LS and DFHSC2LS provide improved support for <xsd:choice> elements. The assistants generate a new container that stores the value associated with the <xsd:choice> element. The assistants generate language structures containing the name of a new container and an extra field:
fieldname-enum
The discriminating field to indicate which of the options the <xsd:choice> element will use.
fieldname-cont
The name of the container that stores the option to be used. A further language structure is generated to map the value of the option.
The following XML schema fragment includes an <xsd:choice> element:
<xsd:element name="choiceExample">
   <xsd:complexType>
      <xsd:choice>
         <xsd:element name="option1" type="xsd:string" />
         <xsd:element name="option2" type="xsd:int" />
         <xsd:element name="option3" type="xsd:short" maxOccurs="2" minOccurs="2" />
      </xsd:choice>
   </xsd:complexType>
</xsd:element>
If this XML schema fragment is processed at mapping level 2.2 or higher, the assistant generates the following COBOL language structures:
   03 choiceExample.
      06 choiceExample-enum         PIC X DISPLAY.
          88 empty                     VALUE X'00'.
          88 option1                   VALUE X'01'.
          88 option2                   VALUE X'02'.
          88 option3                   VALUE X'03'.
      06 choiceExample-cont         PIC X(16).


01 Example-option1.
   03 option1-length                PIC S9999 COMP-5 SYNC.
   03 option1                       PIC X(255).

01 Example-option2.
   03 option2                       PIC S9(9) COMP-5 SYNC.

01 Example-option3.
   03 option3 OCCURS 2             PIC S9999 COMP-5 SYNC.

Limitations for <xsd:choice> at mapping level 2.2 and higher

DFHSC2LS and DFHWS2LS do not support nested <xsd:choice> elements; for example, the following XML is not supported:
<xsd:choice>
   <xsd:element name ="name1" type="string"/>
   <xsd:choice>
      <xsd:element name ="name2a" type="string"/>
      <xsd:element name ="name2b" type="string"/>
   </xsd:choice>
</xsd:choice>
DFHSC2LS and DFHWS2LS do not support recurring <xsd:choice> elements; for example, the following XML is not supported:
<xsd:choice maxOccurs="2">
   <xsd:element name ="name1" type="string"/>
</xsd:choice>

DFHSC2LS and DFHWS2LS support a maximum of 255 options in an <xsd:choice> element.

Support for <xsd:choice> at mapping level 2.1 and below

At mapping level 2.1 and below, DFHWS2LS provides limited support for <xsd:choice> elements. DFHWS2LS treats each of the options in an <xsd:choice> element as though it is an <xsd:sequence> element that can occur at most once.

Only one of the options in an <xsd:choice> element can be used, so take care when you implement an application using the <xsd:choice> element that you generate only valid combinations of options. Each of the elements has its own count field in the generated languages structure, exactly one of which must be set to 1 and the others must all be set to 0. Any other combination of values is incorrect, except when the <xsd:choice> is itself optional, in which case it is valid for all of the fields to be set to 0.