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Re: Initial thoughts on WSDL2.0 LC101 - do we need message level binding properties?

From: Amelia A Lewis <alewis@tibco.com>
Date: Mon, 7 Feb 2005 14:24:46 -0500
To: "Liu, Kevin" <kevin.liu@sap.com>
Cc: www-ws-desc@w3.org, public-ws-async-tf@w3.org
Message-Id: <20050207142446.7cb9e657.alewis@tibco.com>

On Mon, 7 Feb 2005 19:42:43 +0100
"Liu, Kevin" <kevin.liu@sap.com> wrote:

[several detailed proposals]

I'm going to make an alternative suggestion.  Parameters: must not
require changes to interface, should avoid making deep changes to WSDL,
must permit multi-protocol message exchanges.

Proposal:

Add to the binding or operation a feature^Wcharacteristic:
"uses-addressing".  This characteristic may be [absent], [required], or
[optional].  It has properties: each property represents one supported
protocol binding.

This characteristic may appear per-operation, or it may apply to the
binding as a whole, in which case it applies to each operation (unless
overridden within the operation).

There are two cases: service-initiated operations and
externally-initiated operations (output-first and input-first). 
Single-message exchanges are not interesting, since we're not doing
choreography.  For multi-message, or potentially multi-message
exchanges, the two cases look like this:

1) output-first: there is no significance to the "required/optional"
attribute.  The service will include an address/endpoint reference, one
for each protocol for which it advertises support (using WS-Addressing).
 The output message recipient may reply to any one (only one) of these
addresses.

2) input-first, optional: the operation initiator MAY include an
address/endpoint compatible with one of the protocols advertised.  The
service will respond using this (single) endpoint/address.  If no
address/endpoint is included, the service will use the default response
address for the protocol binding in use.

3) input-first, required: the operation initiator MUST include an
address/endpoint compatible with one of the protocols advertised.  The
service will respond using this (single) endpoint/address.

For exchange patterns containing more than two messages,
required/optional semantics continue: additional messages from the
service will contain a list of endpoints; additional messages to the
service will contain a single endpoint.

EXCEPT: the final message in an exchange need not contain any endpoint
references/addresses, unless the pattern specifies that faults may be
propagated in response to the message.

This can be done easily enough with a WS-Addressing Feature containing
supported-protocol properties.

Amy!
-- 
Amelia A. Lewis
Senior Architect
TIBCO/Extensibility, Inc.
alewis@tibco.com
Received on Monday, 7 February 2005 19:25:10 GMT

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