processi

about processes and engines

the “error participant”

ref : “error participant” thread

A ‘participant’ in OpenWFE talk is someone or something taking part in a process. It’s rather always a something because a user / human will receive a workitem from a worklist.

The idea behind the ‘error participant’ is to define at process or engine level where should workitems go when the engine couldn’t deliver them to the initially intended participant.

I was suggesting to set a variable named ‘__error_participant__’ (yeah, some Python influence…), whose value would be added at the end of the ‘else-ref’ list (see the participant expression documentation about ‘else-ref’).

In theory, it looks fine. The ‘error participant’ could be some trusted participant (why not something within the engine itself ?)… todo #1441589

Here is a small example process definition :

    <sequence>
        <!--
            setting the "error" participant
        -->
        <set variable="__error_participant__" value="error" />
        ...
        <participant ref="reviewer1" />
        <participant ref="reviewer1b" else-ref="reviewer1c" />
        ...
    </sequence>

this would thus be equivalent to writing :

    <sequence>
        ...
        <participant ref="reviewer1" else-ref="error" />
        <participant ref="reviewer1b" else-ref="reviewer1c, error" />
        ...
    </sequence>

Would this make sense ?

What happens if we don’t want an else-ref to be appended to the attributes of a participant reference ?

update : as suggested by Philip, an explicit empy ‘else-ref’ could indicate that the error-participant shouldn’t be added.

        <participant ref="reviewer2" else-ref="" />

Written by John Mettraux

March 2, 2006 at 10:14 am

Posted in bpm, openwfe, workflow

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