SOAP::WSDL::Manual::XSD(3) SOAP::WSDL's XML Schema implementation


SOAP::WSDL's XML Schema implementation translates XML Schema definitions into perl classes.

Every top-level type or element in a XML schema is translated into a perl class (usually in it's own file).

Atomic types are either directly included in the class of their parent's node, or as sub-package in their parent class' file.

While the implementation is still incomplete, it covers the XML schema definitions used by most object mappers.


You can use SOAP::WSDL::XSD based classes just like any perl class - you may instantiate it, inherit from it etc.

You should be aware, that SOAP::WSDL::XSD based classes are inside-out classes using Class::Std::Fast, though - things you would expect from hash-based classes like using the blessed hash ref as data storage won't work.

Moreover, most all SOAP::WSDL::XSD::Typelib based classes override Class::Std::Fast's default constructor for speed - you should not expect BUILD or START methods to work, unless you call them yourself (or define a new constructor).

All SOAP::WSDL::XSD based complexType classes allow a hash ref matching their data structure as only parameter to new(). You may mix hash and list refs and objects in the structure passed to new - as long as the structure matches, it will work fine.

All SOAP::WSDL::XSD based simpleType (and builtin) classes accept a single hash ref with the only key ``value'' and the value to be set as value.


Array dereference

All SOAP::WSDL::XSD based classes overload arrayification - that is being accessed as a list ref - with a method returning [ $self ].

This means that you can safely use the results of get_ELEMENT calls on complexTypes as list refs (you'll have to check for definedness, though - see SOAP::WSDL::XSD::Typelib::Builtin for details.

To iterate over a (potential) list of child elements just do the following:

 if (defined $obj->get_ELEMENT()) {
     for (@{ $obj->get_ELEMENT() }) {

This is especially useful in mini-languages like HTML::Template::Compiled, where you could say

 <%IF_DEFINED obj.get_ELEMENT %>
    <%LOOP obj.get_ELEMENT %>

Note that this does not work in HTML::Template::Compiled yet - the code generated for the template checks UNIVERSAL::isa instead of dereferencing. There's a ticket open in HTC to solve the issue.


SOAP::WSDL::XSD::Typelib::ComplexType based objects have a method as_hash_ref, which returns the object's content as a hash reference.

This can be convenient for cloning:

 my $class = ref $old;
 my $clone = $class->new( $old->as_hash_ref() );

To convert from one type to another, you can just say

 my $new = MyTypes::NewType->new( $old->as_hash_ref() );

Of course this will only work if MyTypes::NewType has a superset of the old object class' elements.

Note that XML attribute data is not included in the hash ref output yet.


Base classes

SOAP::WSDL::XSD provides a set of base classes for the construction of XML schema defined type classes.

Builtin types

SOAP::WSDL::XSD provides classes for all builtin XML Schema datatypes.

For a list and reference on these classes, see SOAP::WSDL::XSD::Typelib::Builtin.

Derivation classes

For derivation by list, the list derivation class SOAP::WSDL::XSD::Typelib::Builtin::list exists.

Derivation by restriction is handled without the help of additional classes.

Element construction class

For the construction of element classes, the element superclass SOAP::WSDL::XSD::Typelib::Element exists. All elements are ultimately derived from this class. Elements may inherit from type classes, too - see ``TRANSLATION RULES'' for details.

complexType construction class

For the construction of complexType classes, the construction class SOAP::WSDL::XSD::Typelib::ComplexType is provided. It provides a __factory method for placing attributes in generated classes, and generating appropriate setter/getter accessors.

The setters are special: They handle complex data structures of any type (meaning hash refs, list refs and objects, and any combination of them), as long as their structure matches the expected structure.



TODO add more elaborate description

element with type attribute

Elements defined by referencing a builtin or user defined type inherit from SOAP::WSDL::XSD::Typelib::Element and from the corresponding type class.

  Element       Type
  base class    class
     ^            ^
     |            |
 Element type="" class

element with ref attribute

Elements defined by referencing another element inherit from the corresponding element class.

 referenced Element class
 Element ref="" class

element with atomic simpleType

Elements defined by a atomic simpleType from SOAP::WSDL::XSD::Typelib::Element and from the base type of the atomic type.

   Element     atomic Type
  base class   base class
     ^              ^
     |              |
 element simpleType class

element with atomic complexType

Elements defined with a atomic complexType inherit from SOAP::WSDL::XSD::Typelib::Element and from SOAP::WSDL::XSD::Typelib::ComplexType.

   Element     complexType
  base class   base class
     ^              ^
     |              |
 element complexType class


TODO add more elaborate description

Some content models are not implemented yet. The content models implemented are described below.

complexType with ``all'' variety

Complex types with ``all'' variety inherit from SOAP::WSDL::XSD::Typelib::ComplexType, and call it's factory method for creating fields and accessors/mutators for the complexType's elements.

All element's type classes are loaded. Complex type classes have a ``has a'' relationship to their element fields.

Element fields may either be element classes (for element ref="``) or type classes (for element type=''"). No extra element classes are created for a complexType's elements.

  base class
 complexType all
 ----------------     has a
 element name="a" ------------> Element or type class object
 element name="b" ------------> Element or type class object

The implementation for all does enforce the order of elements as described in the WSDL, even though this is not required by the XML Schema specification.

complexType with ``sequence'' variety

The implementation of the ``sequence'' variety is the same as for all.

complexType with ``choice'' variety

The implementation for choice currently is the same as for all - which means, no check for occurrence are made.

complexType with complexContent content model

Note that complexType classes with complexContent content model don't exhibit their type via the xsi:type attribute yet, so they currently cannot be used as a replacement for their base type.

SOAP::WSDL's XSD deserializer backend does not recognize the xsi:type="" attribute either yet.

  • restriction variety

    ComplexType classes with restriction variety inherit from their base type. No additional processing or content checking is performed yet.

      base type class
  • extension variety

    ComplexType classes with extension variety inherit from the XSD base complexType class and from their base type.

    Extension classes are checked for (re-)defining all elements of their parent class.

    Note that a derived type's elements (=properties) overrides the getter / setter methods for all inherited elements. All object data is stored in the derived type's class, not in the defining class (See Class::Std for a discussion on inside out object data storage).

    No additional processing or content checking is performed yet.

      complexType        complexType
      base class       base type class
           ^                 ^
           |                 |


TODO add more elaborate description

Some derivation methods are not implemented yet. The derivation methods implemented are described below.

Derivation by list

Derivation by list is implemented by inheriting from both the base type and SOAP::WSDL::XSD::Typelib::XSD::list.

Derivation by restriction

Derivation by restriction is implemented by inheriting from a base type and applying the required restrictions.


XML Schema facets are not implemented yet.

They will probably implemented some day by putting constant methods into the correspondent classes.


The attribute set for a XML element (derived from anySimpleType or complexType) is implemented as a sub-package of the element derived from SOAP::WSDL::XSD::Typelib::AttributeSet.

The sub-package is named as the corresponding type or element package, suffixed with "XmlAttr". The suffix ``XmlAttr'' has carefully been chosen to avoid potential naming clashes: The name XmlAttr cannot be included as element or type name in XML schemas - the XML standard bans the use of names starting with ``xml'' (case-insensitive).

All XML attributes for a XML element are set- and retrievable via the method "attr". The name is chosen to allow mimicking SOAP::Lite's behaviour, which allows setting a SOAP::Data object's attributes via "attr".

 my $attrSet = $obj->attr();
     whitespace => 'preserve',
     nillable => 1,

SOAP::WSDL::XSD::Typelib::AttributeSet is derived from SOAP::WSDL::XSD::Typelib::ComplexType with content model "all". The individual attributes can be set and retrieved via the respective set_FOO / get_FOO methods.

The "attr" method provides auto-vivification: An xml object's attribute set is instantiated when accessed.

Auto-vivification is only triggered if there actually is a set of attributes for the class/object in question, so you may want to test whether the result of ->attr is defined:

 my $attr = $unknownObject->attr();
 if (defined($attr)) {
         some => 'value',


CAVEAT: Group resolution is not implemented yet.

XML Schema Group definitions are just treated as aliases that can be inserted in complexType definitions by referencing them. That is, there's no difference between a complexType with simpleContent and a sequence of three elements, and a complexType with simpleContent referencing a group containing the same sequence of elements.


  • START and BUILD are not being called

    In contrast to ``normal'' Class::Std::Fast based objects, the classes of the SOAP::WSDL::XSD::Typelib:: hierarchy (and all type and element classes generated by SOAP::WSDL) override Class::Std's constructor for performance reasons.

    If you inherit from such a class and place a START or BUILD method in it, it will not get called - at least not unless you place something like this at the top of you code:

     use Class::Std::Fast::Storable;

    In this case, Class::Std::Fast::Storable will export a new() method into your class, which in turn calls START and BUILD.

    The constructors of all SOAP::WSDL::XSD::Typelib:: classes don't !


The following XML Schema declaration elements are not supported yet:

XML Schema elements partially supported

Type definition elements
  • simpleContent

    simpleContent is only supported with a restriction or extension with a "base" attribute. simpleContent declarations deriving from a atomic type are not supported (yet).

Inclusion elements

  • import

    The import inclusion element requires the schemaLocation attribute for resolving the XML schema to import. Support for the import element is implemented in SOAP::WSDL::Expat::WSDLParser, so alternative parsers may or may not support the import element.

    SOAP::WSDL::Expat::WSDLParser keeps track of included schemas and prevents import loops.


The following XML Schema declaration elements are supported, but have no effect yet.

  • enumeration
  • fractionDigits
  • length
  • maxExclusive
  • maxInclusiove
  • maxLength
  • minExclusive
  • minInclusive
  • minLength
  • pattern
  • totalDigits
  • whitespace

XML Schema elements not implemented

Declaration elements
  • notation

Content model definition elements

  • any

    The horror of each XML schema implementation: Just anything...

    "any" declarations are not supported yet.

  • anyAttribute
  • attributeGroup

    "attributeGroup" declarations actually just are macros for XML Schema writers: Including an attributeGroup in a declaration has the same effect as including all attributes in the group.

    Just not implemented yet.

  • group

    The group definition element is not supported yet.

Identity definition elements

These declaration elements don't declare XML elements, but apply identity constraints. They have no effect yet.

  • field
  • key
  • keyref
  • selector
  • unique

Inclusion elements

  • include

    Use of the include inclusion element is forbidden by the WS-I basic profile. It is not supported (yet).

  • redefine

    Not supported (yet).

* Documentation elements

  • appinfo

    The appinfo documentation element is ignored.


Copyright 2007,2008 Martin Kutter.

This file is part of SOAP-WSDL. You may distribute/modify it under the same terms as perl itself


Martin Kutter <martin.kutter>


 $Rev: 390 $
 $LastChangedBy: kutterma $
 $Id: 390 2007-11-16 22:18:32Z kutterma $
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