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updated proposal on issue #144 - array metadata in SOAP Encoding

From: Jacek Kopecky <jacek@systinet.com>
Date: Tue, 6 Nov 2001 11:16:54 +0100 (CET)
To: <xml-dist-app@w3.org>
Message-ID: <Pine.LNX.4.33.0111061023580.16358-100000@mail.idoox.com>
 Hello all. 8-)
 This message is an updated proposal for how we can encode arrays
in SOAP Encoding in more XML-like way.

 See [1] for background information on this proposal.

 Summary of the changes in this update:
 1) offset indicates nothing is below it (see [2])
 2) elements must appear in order (see [2])
 3) Andrew's algorithm (see [3]) added - this removes the
constraint that if any member specifies its position, every
member in the same array must do so.
 4) made rule #8 just point to the subsection on array
serialization because otherwise the rule is confusingly long
compared with the rest of rules.


 ------------------------------ the proposal begin
 4.1 rule #8
 Arrays are compound values. SOAP Encoding
arrays are defined as having a type of "enc:Array" or a type
derived there from. See subsection 4.4.2 for specific rules on
array serialization.


 4.4.2 Arrays
 SOAP Encoding arrays have one or more dimensions. An array value
is represented as a series of elements reflecting the array. There
is no specific constraint on the names of the member elements. The
members MUST appear in ascending ordinal sequence; for
multi-dimensional arrays the dimension on the right side varies
most rapidly.
 Array types derived from enc:Array MUST be restrictions of the
enc:Array type and can be used to represent, for example, arrays
limited to integers or arrays of some user-defined enumeration.
 SOAP Encoding arrays can be single-reference or multi-reference
values, and consequently may be represented as the content of
either an embedded or independent element. The elements which make
up the array can themselves can be of any type, including nested
arrays.
 A SOAP Encoding array MAY contain an enc:arraySize attribute of
the type "List of (positiveInteger or '*')" whose items mean the
sizes in each of the array's dimensions (unspecified size in case
of the asterisk). The number of the sizes representes the number
of dimensions of this array. The default value of this attribute
is "*". For example, enc:arraySize="3 5" attribute signifies a
two-dimensional array with three rows and five columns.
enc:arraySize="* 5" signifies a two-dimensional array with an
unspecified number of rows and five columns.
 In case there is an asterisk on other than the first position,
all the members in the array MUST specify their position.
 A SOAP Encoding array MAY contain an enc:itemType attribute of
the type QName. This type specifies the base type for the type of
every member of the array. The default value of this attribute is
anyType. Each member's type MUST be a subtype of itemType or it
must be the itemType itself.
 A SOAP Encoding array MAY contain an enc:offset attribute
indicating that there is no member in this array on position below
the value of this attribute. This can be used to indicate the
offset position of a partially represented array (see 4.4.2.1
Partially Transmitted Arrays).
 Likewise, members of an array MAY contain an enc:position
attribute indicating the position of that member in the enclosing
array. This can be used to describe members of sparse arrays (see
4.4.2.1 Partially Transmitted Arrays). The position attribute MUST
NOT indicate a position below the offset (if present) or below the
position of the previous member in the array.
 The value of the enc:offset and the enc:position attribute is of
type "List of nonNegativeInteger" with offsets and positions based
at 0.
 In the presence of both offset and position the position
attribute is absolute, it is not relative to the offset value.
 The highest position of a member in an array must not be greater
than the size of the array. No two members in an array may specify
the same position.
 The position of a member is computed assording to the following:

If the member has an explicit position attribute,
    that position attribute indicates the position exactly
Else
    If there was a prior element in the encoding,
        the member has the position following the prior element's
        position in the array,
    Else
        If there is an offset attribute, position is given by
            the value of the offset,
        Else position is zero in all dimensions.



 [stripped examples and schemata updated according to the rules above]

 4.4.2.1 Partially Transmitted Arrays
 SOAP Encoding provides support for partially transmitted arrays -
arrays in which some members are not transmitted. SOAP Encoding
provides two options of skipping some members:
 1) skipping the beginning and the ending of an array,
 2) specifying the exact positions of members in an array.
 The first option uses the attribute enc:offset to specify
how much of the beginning of the array is skipped. Skipping the
ending of an array is done by simply not transmitting the members
at the end. For example:

<enc:Array enc:offset="2 2" enc:arraySize="4 3">
   <x>3rd row, 3rd col</x>
   <x>4th row, 1st col</x>
   <x>4th row, 2nd col</x>
</enc:Array>

 The second option uses the attribute enc:position on the members,
following rules set above.
 ------------------------------ the proposal end



                            Jacek Kopecky

                            Systinet, Inc.
                            http://www.systinet.com/



[1] http://lists.w3.org/Archives/Public/xml-dist-app/2001Oct/0295.html
[2] http://lists.w3.org/Archives/Public/xml-dist-app/2001Oct/0362.html
[3] http://groups.yahoo.com/group/soapbuilders/message/5126
Received on Tuesday, 6 November 2001 05:17:29 GMT

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