Web Services Conversation Language (WSCL) - PowerPoint PPT Presentation

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Web Services Conversation Language (WSCL)

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Title: Web Services Conversation Language (WSCL)

1
Web Services Conversation Language(WSCL)

Joy Lin
November 18 2003

2
Contents

Introduction
Elements of a WSCL specification
- Document types
- Interactions
- Transitions
- Conversations
Example

3
What is WSCL?

Web Services Conversation Language.
WSCL conversation definitions are themselves XML
documents.
Specifies the XML documents being exchanged, and
the allowed sequencing of these document
exchanges.
WSCL and WSDL are highly complimentary WSDL
specifies how to send messages to a service and
WSCL specifies the order in which such message
can be sent.

4
Elements of a WSCL Specification

There are four main elements of a WSCL
specification
Document type descriptions
Interactions
Transitions
Conversations

5
Document type descriptions

Specify the types (schemas) of XML documents the
service can accept and transmit in the course of
a conversation.
The document schemas are separate XML documents
referenced by their URL in the XMLDocumemtType
elements of the conversation specification
InboundXMLDocument
OutboundXMLDocument

6
Example

hrefSchema - refers to the schema to which the
documents corresponds.
id - can be used within the rest of the
conversation definition.
Example An input document that conforms to a
purchase order schema defined in
PurchasedOrderRQ.xsd.

ltInboundXMLDocument hrefSchemahttp//foo.o
rg/PurchasePrderRQ.xsd idPurchaseOrderRQ
lt/InboundXMLDocumentgt
7
Interactions

An interaction is an exchange of documents
between a service and its client.
WSCL only models business level interactions. It
only specifies which business level documents are
exchanged and does not model how this exchange is
carried out by lower-level messaging protocols.
One-Way Interactions
Send the service sends out an outbound
document.
Receive the service receives an inbound
document.

8
Interactions

Two-Way Interactions
SendReceive the service sends out an outbound
document and then expects to receive an inbound
document in reply.
ReceiveSend the service receives an inbound
document and then sends out an outbound document.
Empty does not contain any documents exchanged,
but is used only for modeling the start and end
of a conversation.

9
Example One-Way Interactions

One-Way interactions represent a single one-way
message being sent or received by a participant.
This example represents a Receive interaction
that receives a login document.

ltInteraction interactionType"Receive"
id"LoginRegInput"gt ltInboundXMLDocument
id"LoginRequestData"
hrefSchemahttp//foo.org/LoginRequestData.xsdgt
lt/InboundXMLDocumentgt lt/Interactiongt
10
Example Two-Way Interactions

A SendReceive example Each SendReceive
interaction is the logical unit of sending a
request and then receiving a response. The
interaction is not complete until the response
has been exchanged.

ltInteraction interactionType"SendReceive"
id"Payment"gt ltOutboundXMLDocument
id"Invoice" hrefSchema"http//foo.o
rg/InvoiceRS.xsd"gt lt/OutboundXMLDocumentgt
ltInboundXMLDocument id"Payment
hrefSchema"http//foo.org/Payment.xsd"gt
lt/InboundXMLDocumentgt lt/Interactiongt
11
Example Two-Way Interactions

This example shows a Purchase interaction that
specifies two additional outbound document types
for the case of invalid payment and out of stock.

ltInteraction interactionType"ReceiveSend"
id"Purchase" gt ltInboundXMLDocument
id"PurchaseOrderRQ"
hrefSchema"http//conv123.org/PurchaseOrderRQ.xsd
" gt lt/InboundXMLDocumentgt
ltOutboundXMLDocument id"PurchaseOrderAcceptedRS"
hrefSchema"http//conv123.org/Purchas
eOrderAcceptedRS.xsd" gt lt/OutboundXMLDocumentgt
ltOutboundXMLDocument id"InvalidPaymentRS"
hrefSchema"http//conv123.org/Invalid
PaymentRS.xsd" gt lt/OutboundXMLDocumentgt
ltOutboundXMLDocument id"OutOfStockRS"
hrefSchema"http//conv123.org/OutOfStockRS.xsd"
gt lt/OutboundXMLDocumentgt lt/Interactiongt
12
Transitions

Transitions specify the ordering relationships
between interactions.
SourceInteracion precede the DestinationInteract
ion when the conversation is executed.
DestinationInteraction follow the
SourceInteraction when the conversation is
executed.
SourceInteractionCondition an additional
condition for the transition. (Optionally)

13
Example
ltTransitiongt ltSourceInteraction
href"Login"/gt ltDestinationInteraction
href"Login"/gt ltSourceInteractionCondition
href"InvalidLoginRS"/gt lt/Transitiongt
ltTransitiongt ltSourceInteraction
href"Login"/gt ltDestinationInteraction
href"Purchase"/gt ltSourceInteractionCondition
href"ValidLoginRS"/gt lt/Transitiongt
14
Initial and Final Interactions

Part of defining the possible ordering of
interactions is the specification of the first
and last interactions of a conversation.
initialInteraction references the ID of the first
interaction to be executed in the conversation.
finalInteraction references the ID of the last
interaction to be executed in the conversation.
Example

ltConversation nameExampleConversation
initialInteraction Login
finalInteraction Purchasegt
15
Initial and Final Interactions

There might be more than one interaction with
which the conversation can start or end.
To specify several possible start and end
interactions, interactions of type Empty is used.
An interaction type Empty is an interaction in
which no documents are exchanged. Currently, the
only situation in which Empty interactions can be
used in a conversation definition is when several
possible final or initial interactions need to be
modeled.

16
Conversation

Conversations list all the interactions and
transitions that make up the conversation.
A conversation contains additional information
about the conversation, including the
conversations name and the interaction the
conversation can start with and end with.
The Conversation element contains the following
two sub elements
ConversationInteractions list all Interaction
elements.
ConversationTransitions lists all Transition
elements.

17
Conversation

The Conversation element contains the following
attributes
initialInteraction and finalInteraction
name the name of the conversation
version(optional) the version of the
conversation.
targetNamespace(optional) the namespace of this
conversation as it should be used when elements
of this conversation are referenced in other XML
documents.
hrefSchema(optional) the URL of the file
containing this conversation definition.
description(optional)

18
Example

lt?xml version"1.0" encoding"UTF-8"?gt
ltConversation namesimpleConversation"
version"1.01
xmlns"http//www.w3.org/2002/02/wscl10"
initialInteraction"Start"
finalInteraction"End
description"Conversation for a Store Front
Service"
ltConversationInteractionsgt
list of all the interactions
lt/ConversationInteractionsgt
ltConversationTransitionsgt
list of all the transitions
lt/ConversationTransitionsgt
lt/Conversationgt

19
Example purchase conversation definition
login ReceiveSend
InvalidLoginRS
ValidLoginRS
Purchase ReceiveSend
PurchaseAcceptRS
OutOfStockRS InvalidPaymentRS
shipping Send
20
Example purchase conversation definition