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Re: Issue 742 - Proposal for discussion

From: Gary Brown <gary@enigmatec.net>
Date: Thu, 16 Sep 2004 09:38:32 +0100
Message-ID: <002001c49bc8$9063f190$4b00a8c0@LATTITUDEGary>
To: "Nickolas Kavantzas" <nickolas.kavantzas@oracle.com>, <public-ws-chor@w3.org>

Hi Nick

What is the requirement for the globalizedTrigger function?

Do you have a concrete use case where this is required?

Regards
Gary

----- Original Message ----- 
From: "Nickolas Kavantzas" <nickolas.kavantzas@oracle.com>
To: <public-ws-chor@w3.org>
Sent: Wednesday, September 15, 2004 4:54 PM
Subject: Issue 742 - Proposal for discussion


>
> For resolving issue 742
(http://www.w3.org/Bugs/Public/show_bug.cgi?id=742) here is my
> proposal:
>
>
> Here are the proposed changes for section 2.4.5:
>
> The following rules apply for a Work Unit matching:
>
>  When a guard condition is not specified then the Work Unit always
matches
>  When a repetition condition is not specified then the Work Unit is not
matched again
>  When a guard condition or repetition condition is specified then:
> o One or more variables can be specified in a guard condition or
repetition condition, using XPATH and the WS-CDL functions, as described in
Section 10.
> o The WS-CDL function getVariable() is used in the guard or repetition
condition to obtain or set the information of a variable
> o When the WS-CDL function isVariableAvailable() is used in the guard or
repetition condition, it means that the Work Unit that specifies the guard
condition is checking if a variable is already available at a specific Role
or is waiting for a variable to become available at a specific Role
> o When the WS-CDL function variablesAligned() is used in the guard or
repetition condition, it means that the Work Unit that specifies the guard
or repetition condition is waiting for an appropriate alignment Interaction
to happen between the two Roles. When the variablesAligned() WS-CDL function
is used in a guard or repetition condition, then the Relationship Type
within the variablesAligned() MUST be the subset of the Relationship Type
that the immediate enclosing Choreography defines. In the example below, the
guard condition specifies that the enclosed Work Unit is waiting for an
alignment Interaction to happen between the customer Role and the retailer
Role:
>
> guard="cdl:variablesAligned(
>                "PurchaseOrderAtBuyer", "PurchaseOrderAtSeller",
>                "customer-retailer-relationship")"
> o If variables are defined at different Roles, then they can be combined
together in a guard condition or repetition condition using only the
globalizedTrigger() WS-CDL function
> o If variables are defined at the same Role, then they can be combined
together in a guard condition or repetition condition using all available
XPATH operators and the WS-CDL functions except the globalizedTrigger()
WS-CDL function
> o When the block attribute is set to "false", then the guard condition or
repetition condition assumes that the variable information is currently
available.
> o If either the variable information is not available or the guard
condition evaluates to "false", then the Work Unit matching fails and the
Activity-Notation enclosed within the Work Unit is skipped.
> o If either the variable information is not available or the repetition
condition evaluates to "false", then the Work Unit is not matched again.
> o When the block attribute is set to "true" and one or more variable(s)
are not available, then the Work Unit MUST block waiting for the variable
information to become available.
> o When the variable information specified by the guard condition become
available then the guard condition is evaluated. If the guard condition
evaluates to "true", then the Work Unit is matched. If the guard condition
evaluates to "false", then the Work Unit matching fails and the
Activity-Notation enclosed within the Work Unit is skipped.
> o When the variable information specified by the repetition condition
become available then the repetition condition is evaluated. If the
repetition condition evaluates to "true", then the Work Unit is matched
again. If the repetition condition evaluates to "false", then the Work Unit
is not matched again.
>
>
>
> Here are the proposed changes for section 10:
>
> 10 WS-CDL Supplied Functions
> There are several functions that the WS-CDL specification supplies as
XPATH 1.0 extension functions. These functions can be used in any XPath
expression as long as the types are compatible.
>
> ...
> xsd:any getVariable(xsd:string varName, xsd:string documentPath?,
xsd:QName  roleName?)
> Returns the information of the variable with name varName as a node set
containing a single node. The second parameter is optional. When the second
parameter is not used, this function retrieves from the variable information
the entire document. When the second parameter is used, this function
retrieves from the variable information, the fragment of the document at the
provided absolute location path. The third parameter is optional. When the
third parameter is used that the variable information MUST be available at
the Role specified by roleName. If this parameter is not used then the Role
is inferred from the context that this function is used.
>
> xsd:boolean isVariableAvailable(xsd:string varName, xsd:QName  roleName)
> Returns "true" if the information of the variable with name varName is
available at the Role specified by roleName. Returns "false" otherwise.
>
> xsd:boolean variablesAligned(xsd:string varName, xsd:string withVarName,
>                                                xsd:QName
relationshipName)
> Returns "true" if within a Relationship specified by relationshipName the
variable with name varName residing at the first Role of the Relationship
has aligned its information with the variable named withVarName residing at
the second Role of the Relationship.
>
> xsd:boolean globalizedTrigger(xsd:string expression, xsd:string roleName,
xsd:string expression2, xsd:string roleName2, .)
> Combines expressions that include variables that are defined at different
Roles.
>
>
>
> --
> Nick
>
>
>
>
>
>
Received on Thursday, 16 September 2004 08:39:17 GMT

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