Syntactic Convention for Attributes

Folks,

As I promised on Monday's concall, I have crafted a syntactic convention 
for WSDL. It is not perfect (not done much proof reading), but just to 
give you an idea what I am thinking. This *is* a syntactic sugar, not a 
proposal to change the component model. It is complementary to the rules 
that are defined in [1].

This is basically reverse engineering of what we have with one added 
rule, (4) and clarifications with  (5) and (6). Rule (4) allows the 
capability for bulk set/get that needs to be defined later, elsewhere.

Let me know what you think about this proposal. Again, I would like to 
discuss this proposal within the context of  [1].
This is NOT to create another discussion about why some people don't 
like attributes. ;-)  So I will appreciate if you could send comments 
with this goal in mind.

Thanks.

--umit

[1] 
http://lists.w3.org/Archives/Public/public-ws-desc-state/2003Oct/0020.html

-- 
Umit Yalcinalp                                  
Consulting Member of Technical Staff
ORACLE
Phone: +1 650 607 6154                          
Email: umit.yalcinalp@oracle.com

Syntactic Sugar for Defining Attributes in WSDL 2.0: 


(1) Define the schema for defining an attribute:

<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'
           targetNamespace='http://www.w3.org/@@@@/@@/wsdl/style/attribute'
           xmlns:attributes='http://www.w3.org/@@@@/@@/wsdl/style/attribute'
           elementFormDefault='qualified'>

        <xs:element name="attribute">
	        <xs:complexType>
			<xs:attribute name="elementReference" 
				type="xs:QName" use="required"/>
			<xs:attribute name="access" 
				type="attributes:enumeration" 
				use="required"/>
			<xs:attribute name="style" 
				type="xs:anyURI"/>
		</xs:complexType>
	</xs:element>

	<xs:simpleType name="enumeration">
		<xs:restriction base="xs:string">
			<xs:enumeration value="read"/>
			<xs:enumeration value="write"/>
			<xs:enumeration value="read-write"/>
		</xs:restriction>
	</xs:simpleType>

</xs:schema>

Note that this attribute is in its own namespace, "attribute", since
we can not share the namespace from "get-attribute" or
"set-attribute". 


(2) The attribute element may appear as a child of the interface
definition as an extension. 

Example: 

<definitions>
  <interface>
    <operation
          name="xs:NCName" 
          pattern="xs:anyURI"
          style="xs:anyURI"? >
      <documentation />?
      [ <feature /> | <property /> | 
        [ <input /> | <output /> | <infault /> | <outfault /> ]+
      ]*
    </operation>
  <attributes:attribute elementReference="tns:foo"
                        access="read-write"/>*
  </interface>
</definitions>

(3) If an attribute element appears as a child of the interface
definition in a WSDL document, it indicates a shortcut for defining a
set of operations that use the styles, "get-attribute" and
"set-attribute" as follows:

3.1 The elementReference element must be the QName of an
element in the document.

3.2 For each elementReference element specified within an
attribute element, the following operations are assumed. 

3.2.1. If the value of the access attribute is "read",
then, the presence of the attribute element is equivalent to the 
following declarations:

Types: The following two elements must be present. 

(a) a global empty element declaration named "get_{Y}".  

(b) a global element declaration named get_{Y}Response defined as a
complex type that contains a sequence that contains with a single
child element. The element must be a reference to the element designated 
by the QName specified in the elementReference attribute.

Operations: One operations must be present in WSDL 
definition and contrained as follows: 

(c) 

- An interface operation must be named "get_{Y}. 

- The interface operation must have the style attribute and its value
must be "http://www.w3.org/@@@@/@@/wsdl/style/get-attribute".

- The interface operation must have a pattern attribute and its value
must be "http://www.w3.org/@@@@/@@/wsdl/in-out". 

- The body attribute of the input element must contain the QName of
the empty element declared in (a). 

- The body attribute of the output element must contain the QName of
the element declared in (b). 

3.2.2 If the value of the access attribute is "write", then the
presence of the attribute element in an interface declaration is
equivalent to the following declarations: 

Types: 

(d) a global element declaration named set_{Y} defined
as a complex type that contains a sequence with a single child element. 
The element must be a reference to the element designated 
by the QName specified in the elementReference attribute. 

(e)A global empty element declaration named "set_{Y}Response". 


Operations: One operations must be present in WSDL 
definition and contrained as follows: 

(c) 

- An interface operation must be named "set_{Y}. 

- The interface operation must have the style attribute and its value
must be "http://www.w3.org/@@@@/@@/wsdl/style/set-attribute".

- The interface operation must have a pattern attribute and its value
must be "http://www.w3.org/@@@@/@@/wsdl/in-out". 

- The body attribute of the input element must contain the QName of
the empty element declared in (d). 

- The body attribute of the output element must contain the QName of
the element declared in (e). 

3.2.3 If the value of the access attribute is "read-write", then the
presence of the attribute element in an interface declaration is
equivalent to having both the declarations specified in 3.2.1 and
3.2.2.  

In addition, the naming conventions for choosing a value for {Y}
must follow the restrictions that are specified for WSDL get/set
attribute style document.

(4) Typically, the style attribute in an attribute declaration will
not contain a value. If this attribute has a value, it may indicate
additional operations that may be relevant for a WSDL processor that
would process these styles. For example, additional rules and
operations may be defined for bulk get/set operations and would be
indicated with an appropriate style URI that the processors may
utilize.

(5) It is an error if operations/types that are named and further
defined in 3.2.1, 3.2.2 and 3.2.3 as a result of this convention do
exist in the WSDL document, but their definitions do not match the
requirements presented in these sections. 

(6) This syntactic convention is a normative for declaring
attributes. This syntactic convention is not required to be understood
for WSDL processors, but recommended to be supported by those that
recognize get/set attribute styles as additional convenience for
users.