ignoring elements order in xml validation against xsd

xml validation xsd

10,232

Yes, it is possible. Just create a choice (in some type or element content model, of course) with maxOccurs set to unbounded.

<xs:element name="headers">
    <xs:complexType>
        <xs:choice maxOccurs="unbounded">
            <xs:element name="subject" type="xs:string"/>
            <xs:element name="recipient" type="xs:string"/>
        </xs:choice>
    </xs:complexType>
</xs:element>

10,232

Author by

Segolas

Updated on June 14, 2022

Comments

Segolas almost 2 years
Ia processing an email and saving some header inside a xml document. I also need to validate the document against a xml schema.

As the subject suggest, I need to validate ignoring the elements order but, as far as I read this seems to be impossible. Am I correct?

If I put the headers in a<xsd:sequence>, the order obviously matter. If I us <xsd:all> the order is ignored but for some strange reason this imply that the elements must occur at least once.

My xml is something like this:
```
<headers>
  <subject>bla bla bla</subject>
  <recipient>[email protected]</recipient>
  <recipient>rcp02domain.com</recipient>
  <recipient>[email protected]</recipient>
</headers>
```
but I think the final document is valid even if subject and recipient elements are swapped.

There is really nothing to do?
InfantPro'Aravind' almost 14 years

@segolas, I can see that this solution meets your requirement, please show courtesy to accept the solution.
Segolas almost 14 years

I'm working on Netbeans, and using this solution gives me some errors I'm trying to figure out. So, by now I don't know if this answer works or not!
Segolas almost 14 years

Unfortunaly I posted just an example of what my xml is and in fact I have lots of elements. I understand your solution but I think would make my schema less readable and a little too hard to maintain...
Segolas almost 14 years

Hum... i think it worked, but right now jaxb generate a method getSubjectOrRecipient() instead of getSubject() AND getRecipient(). According to w3schools.com/Schema/el_choice.asp "XML Schema choice element allows only one of the elements contained in the <choice> declaration to be present within the containing element." So, it seems I can only have subject OR recipient inside the headers element... am I right?
xcut almost 14 years

Hi segolas; FYI, if you are using JAXB, then as soon as you create an unbounded sequence or unbounded choice (rather than unbounded elements within them), then JAXB is forced to generate this intermediate method to correctly reflect the repeating choice. However, regardless: you can repeat the elements as often as you want. Each choice can only have one, yes, but the choice itself is repeatable :)
Segolas almost 14 years

Ok, got it. Just one thing, I want both <subject> and <recipient> and a xml without one of these two tags should be invalid. Is this the case? Maybe I can try with minOccurs=1 ?
xcut almost 14 years

The default for minOccurs is 1 in any case. Unfortunately, the thing you want (unlimited mixed list AND at least one of each item) is impossible to express in XML Schema.. you'll have to validate it on the JAXB graph after loading.
Segolas almost 14 years

Ok, perfect. Thanks for your time!