Issue - 208 - Partner Link Equivalence

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Issue - 208 - Partner Link Equivalence

Status: received
Date added: 20 May 2005
Categories: Partner Links
Date submitted: 20 May 2005
Submitter: Yuzo Fujishima
Champion: Yuzo Fujishima <fujishima@bc.jp.nec.com>
Document: WS-BPEL specification draft
Description:

Partner links are compared in correlating messages. The current specification does not completely define how partner links are compared.

More specifically, the following questions must be answered:

Q1: Is only the partner link QName (process namespace + partner link NCName) considered?

Q2: Is the scope where the partner link is defined considered also?

Q3: Is the EPR assigned to the partner link considered also?

Examples:

E1: Is this legal? Will this result in conflicting receive?

<flow>
  <scope>
    <partnerLinks>
      <partnerLink name="theSameName" ...>
    </partnerLinks>
    <receive partnerLink="theSameName" ...>
  </scope>
  <scope>
    <partnerLinks>
      <partnerLink name="theSameName" ...>
    </partnerLinks>
    <receive partnerLink="theSameName" ...>
  </scope>
</flow>

E2: How about this?

<flow>
  <scope>
    <partnerLinks>
      <partnerLink name="theSameName" ...>
    </partnerLinks>
    <sequence>
      <assign EPR1 to the partner link ...>
      <receive partnerLink="theSameName" ...>
    </sequence>
  </scope>
  <scope>
    <partnerLinks>
      <partnerLink name="theSameName" ...>
    </partnerLinks>
    <sequence>
      <assign EPR2 to the partner link ...>
      <receive partnerLink="theSameName" ...>
    </sequence>
  </scope>
</flow>

Discussion:

The source of the problem is that a partner link that should be scoped globally (among processes and web services/clients) is actually scoped locally (within a scope activity).

In my opinion, a globally-scoped thing should be defined at the process level, not at the scope level.
Submitter's proposal:

Base proposal: Only the partner link QName (process namespace URI as the namespace URI, partner link NCName as the local name) is considered while comparing two partner links in message correlation.

Additional proposal A: Throw conflictingPartnerLink fault when more than one partner link with the same name is instantiated.

Additional proposal B: Disallow defining partner links in a scope. They can be defined only at the process level.
Changes: 20 May 2005 - new issue

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