How to handle minoccurs="0" when calling web services?

Question

I have a web service I am trying to call using a mainframe integration product (DataDirect Shadow z/Services), but my question is more of a general one. I want to know how an element defined as minOccurs="0" is typically handled. The operation on the 3rd party service I am calling has a complexType element where all of the elements within it are marked minOccurs="0".

Example from WSDL

<xs:element minOccurs="0" name="Request">
    <xs:complexType>
        <xs:sequence>
            <xs:element minOccurs="0" name="startDate" type="xs:dateTime"/>
            <xs:element minOccurs="0" name="endDate" type="xs:dateTime"/>
            <xs:element minOccurs="0" name="requestId" type="tns:ObjectName"/>
            <xs:element minOccurs="0" name="reasonCode" type="xs:string"/>
            <xs:element minOccurs="0" name="actionType" type="xs:string"/>
            <xs:element minOccurs="0" maxOccurs="unbounded" name="option" type="xs:string"/>
            <xs:element minOccurs="0" name="comments" type="xs:string"/>
            <xs:element minOccurs="0" name="Name" type="xs:string"/>
        </xs:sequence>
    </xs:complexType>
</xs:element>

The way this service works on the other end, if a value is passed to the service, even if it is null or blank or default, the value will be updated on the 3rd party system. I need a way to OMIT that element in the payload to the service. How is that generally handled? I have tried using C# as a client for this service but the only thing I can find that they provide is the Specified suffixed variable for non-primitive types, but didn't find a way to omit primitive ones. If I was calling this web service by simply POSTing the SOAP message to the 3rd party server I could simply omit the XML for the value I did not want to pass, but I am just wondering how different web service client implementations handle this.

If it helps I believe the 3rd party is using Apache Axis and said they could omit the optional arguments.

Answer 1

When you tried POSTing with the xml part relating to the default/optional arg missing, did you notice any update for that arg at the server (apache axis) side? If you did, then it may be a problem with how the server-side logic had been implemented for that WSDL (not strictly respecting the contract/schema as defined by the WSDL).

Answer 2

I've worked with 3rd Party Web Services that require you to pass a value for all available tags that has a Specified parameter. You can pass pretty much anything in there as long as you set the Specified=false.

Usually you'll get your primitive types to have the Specified tag as well as handling types such as int, bool, double is a problem since they've got default values defined and not setting the Specified tag will cause those values to default to their default defined value.