Title: Namespace for the document fragment representing a part
I think that we should assume that the
elements under the part are fully qualified, meaning that their QName is associated with the namespace in the document
fragment of the part.
-----Original Message-----
From: Ugo Corda
[mailto:]
Sent: Thursday, August 07, 2003 12:56 PM
To:
;
Subject: RE: [wsbpel] Issue - 46 -
Namespace for the document fragment representing a part
Chris,
I don't think I agree with your
final conclusion.
If we decide, as
I proposed, to follow the BP 1.0 resolution, then a part defined
in terms of a type has no namespace (please notice: I am not talking about
default namespace here).
If the part has no namespace, there
is no prefix that can be used to identify the namespace of the top element (as
shown in the BP 1.0 example I pointed out below). This should still be
consistent with what XPath 1.0 says ("if the QName does not have a prefix,
then the namespace URI is null"). So a path starting with
"/PO/..." should be fine.
For what concerns the complete path
example you give, "/PO/tns:Header/tns:PONumber", I don't think the
tns prefix should be there. Assuming that
elementFormDefault="unqualified" for the corresponding schema (which
is the default value), the local elements of purchaseOrder should also be in no
namespace.
Ugo
-----Original Message-----
From: Chris Keller
[mailto:]
Sent: Wednesday, August 06, 2003 7:50 PM
To: Ugo Corda;
Subject: RE: [wsbpel] Namespace
for the document fragment representing a part
Ugo,
I brought up the
issue. I believe this requires
clarification. First in XPath 1.0
there is no default namespace for evaluation meaning that all names need to be
qualified with a prefix. In XPath
2.0 there is the use of a default namespace, but this specification is
referencing 1.0. Putting that aside
for a moment in both 1.0 and 2.0 no namespace is not equal to default
namespace. Let’s take an
example:
<message
name="poMessage">
<part name="PO"
type="tns:purchaseOrder"/>
</message>
<bpws:property
name="poNumber" type="xsd:positiveInteger"/>
<bpws:propertyAlias
propertyName="tns:poNumber"
messageType="tns:poMessage" part="PO"
query="/PO/Header/PONumber"/>
</bpws:propertyAlias>
If as you suggest we
assume that the Part PO is included in the query (which I agree with) and has
no namespace (namespace URI is null) association. This query in order to be correct in
XPath should be formulated as:
/PO/tns:Header/tns:PONumber
Note the section Node
Tests from XPath 1.0 (http://www.w3.org/TR/xpath#node-tests
– section 2.3 Node Tests)
“A node test that
is a QName is true if and only if the type of the node (see [5 Data Model]) is
the principal node type and has an expanded-name equal to the expanded-name
specified by the QName. For example, child::para selects the para element
children of the context node; if the context node has no para children, it will
select an empty set of nodes. attribute::href selects the href attribute of the
context node; if the context node has no href attribute, it will select an
empty set of nodes.
A QName in the node test
is expanded into an expanded-name using the namespace declarations from the
expression context. This is the same way expansion is done for element type
names in start and end-tags except that the default namespace declared with
xmlns is not used: if the QName does not have a prefix, then the namespace URI
is null (this is the same way attribute names are expanded). It is an error if
the QName has a prefix for which there is no namespace declaration in the
expression context.”
-- Note the statement
“except that the default namespace declared with xmlns is not used: if
the QName does not have a prefix, then the namespace URI is null”
Now in XPath 2.0 it is
slightly different (http://www.w3.org/TR/xpath20/#node-tests
– section 3.2.1.2 Node Tests)
“A node test that
consists of a QName is called a name test. A name test is true if and only if
the kind of the node is the principal node kind and the expanded-QName of the
node is equal to the expanded-QName specified by the name test. For example,
child::para selects the para element children of the context node; if the
context node has no para children, it selects an empty set of nodes.
attribute::abc:href selects the attribute of the context node with the QName
abc:href; if the context node has no such attribute, it selects an empty set of
nodes.
A QName in a name test is
expanded into an expanded-QName using the in-scope namespaces in the expression
context. It is a static error if the QName has a prefix that does not
correspond to any in-scope namespace. An unprefixed QName, when used as a name
test on an axis whose principal node kind is element, has the namespaceURI of
the default element namespace in the expression context; otherwise, it has no namespaceURI.”
-- Note the statement:
“An unprefixed QName, when used as a name test on an axis whose principal
node kind is element, has the namespaceURI of the default element namespace in
the expression context; otherwise, it has no namespaceURI.”
-- So in either case we
need to qualify the namespace for your message part declared as a type
example. And if we are following
the XPath 1.0 specification we should qualify all elements that have a
namespace since no default namespace is applied. In this case basically every query in
the bpel specification is incorrect and should contain prefixes for all element
names associated with namespaces in the XPath expressions.
I will continue to submit
the namespace in queries as a new issue unless we want to address it as part of
your original query clarification issue.
Please let me know your thoughts.
Chris
-----Original Message-----
From: Ugo Corda
[mailto:]
Sent: Wednesday, August 06, 2003 9:50 PM
To:
Subject: [wsbpel] Namespace for
the document fragment representing a part
During today's discussion of item 39, somebody
brought up the issue of which namespace is associated with the document
fragment representing a part. This is, of course, relevant to writing path
expressions in query attributes found in assignments and property aliases
declarations.
I imagine this should be an issue only in the case
where the part is defined in terms of a type. (If the part is defined in terms
of an element, I would assume the namespace should be the same as the element's
namespace).
In the case the part is defined in terms of a type, I
would follow what the WS-I Basic Profile 1.0 says in section 5.6.20, Namespace
for Part Accessors:
"R2735 A MESSAGE described with an rpc-literal
binding MUST place the part accessor elements for parameters and return value
in no namespace".
(See also the example in the following section
5.6.21).
In other words, I would follow the same direction and
say that the top element of a document fragment representing a part defined in
terms of a type does not belong to any namespace.
Ugo
