Value equality - and following siblings

Value equality - and following siblings (a co-constraint use case)

Make the content model depend on the value of a particular child element. (In this case, only the following part of the content model need vary.)

source: Valeri Gavrilovets [1]

Other use cases: Co-constraint Use Cases.

Description

The schema should describe two distinct kinds of possible documents:

         <result type="java.util.Hashtable">
            <STATUS>OK</STATUS>
            <Key1>123</Key1>
            <Key2>234</Key2>
            <Key3>324</Key3>
            <Key4>256</Key4>
         </result>

and

    
         <result type="java.util.Hashtable">
            <STATUS>INIT</STATUS>
            <ERROR>200</ERROR>
         </result>

Analysis

(Add your analysis here; see your name in pixels!)

MSM

It's hard to escape the feeling that this would be better done by specifying distinct status_ok and status_nok elements. If there are reasons why that would not work in some situations, I'm having trouble identifying them.

If we removed the Element Declarations Consistent constraint, I suppose one could write something like this:

 <xsd:complexType name="result">
  <xsd:choice>
   <xsd:sequence>
    <xsd:element name="STATUS">
     <xsd:simpleType>
      <xsd:restriction base="xsd:NMTOKEN">
       <xsd:enumeration value="OK">
       </xsd:enumeration>
      </xsd:restriction>
     </xsd:simpleType>
    </xsd:element>
    <xsd:element ref="key1"/>
    <xsd:element ref="key2"/>
    <xsd:element ref="key3"/>
    <xsd:element ref="key4"/>
   </xsd:sequence>

   <xsd:sequence>
    <xsd:element name="STATUS">
     <xsd:simpleType>
      <xsd:restriction base="xsd:NMTOKEN">
       <xsd:enumeration value="INIT">
       </xsd:enumeration>
      </xsd:restriction>
     </xsd:simpleType>
    </xsd:element>
    <xsd:element ref="ERROR"/>
   </xsd:sequence>
  </xsd:choice>
 </xsd:complexType>

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