Recursive XML Elements

[rankam]

Hi There,

We have a requirement for recursive elements within a XML document? Is
it possible to design it through XML Schema? And what are implications
using recursive elements when using DOM Parser in Java?

Any samples demonstrating this concept in XSD is helpful? I need a XML
structure something like this below :

<forms>
<form-name>formName</form-name>
<form-id>1234</form-id>
<secondary>
..... other elements
<secondary>
...... Other Elements
<secondary>
..... Other Elements
</secondary>
</secondary>
</secondary>
<forms>

thanks,
Ramesh ANKAM

 

[Martin Honnen]

We have a requirement for recursive elements within a XML document? Is
it possible to design it through XML Schema?

Yes, certainly.

And what are implications
using recursive elements when using DOM Parser in Java?

None in particular, of course if you do
xmlDocument.getElementsByTagName('element')
or
element.getElementsByTagName('element')
you could end up with elements on different nesting levels then but you
can still process them in document order.

Any samples demonstrating this concept in XSD is helpful?

Here is an XML sample:

<?xml version="1.0" encoding="UTF-8"?>
<element xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="test2005031301Xsd.xml">
<child-element />
<element>
<childElement />
<element>
<element />
</element>
</element>
</element>

and here the schema

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
version="1.0">

<xs:element name="element">
<xs:complexType>
<xs:sequence>
<xs:any processContents="skip" minOccurs="0" />
<xs:element ref="element" minOccurs="0" />
</xs:sequence>
</xs:complexType>
</xs:element>

</xs:schema>

So you can use
<xs:element ref
to refer to the element itself.

And you need to make sure that somewhere the recursion can stop, meaning
the nested element needs to be allowed to not occur where needed for
instance with minOccurs="0".

 

[Ramesh Ankam]

Thanks Martin

Now using "ref" attribute I was able to design a schema with recursive elements.

thanks,
Ramesh