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| bjornwall |
 Posted: Thu Jan 13, 2005 4:34 am Post subject: [SOLVED] No control path? |
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Newbie
Joined: 11 Jan 2005
Posts: 5
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Under which circumstances can this message come out of an FDL import (WF 3.5)?
"There is no control path from 'A' to 'B'"
In my process there is indeed no control path between activites A and B, intentionally. Each activity in the process has a control flow to another activity, but between these two specific activities A and B, there is only a data flow. Are there any rules dictating how control and data flows must be used together?
(And also, is there any way I can attach a picture to this post?)
Thanks
Last edited by bjornwall on Fri Jan 14, 2005 8:12 am; edited 1 time in total |
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| jmac |
| Posted: Thu Jan 13, 2005 5:16 am Post subject: |
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Jedi Knight
Joined: 27 Jun 2001
Posts: 3081
Location: EmeriCon, LLC
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To my knowledge there is no way to attach a picture....
A lesson:
There are 3 types of activity nodes in MQWF:
1) Start Nodes.
2) End Nodes.
3) All others.
A Start Node by definition has NO control connectors going INTO it. When a Process starts MQWF readies all start nodes.
An End Node has No control connectors (or no flow in the case of failed transition conditions) coming out of it. Your nodes A and B with no control connectors are End Nodes. A process is complete when the last End Node that can run (i.e has not been dead path eleminated) completes.
SO, when both A and B complete your process will be complete.
Hope this helps.
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John McDonald
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| bjornwall |
| Posted: Thu Jan 13, 2005 5:46 am Post subject: |
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Newbie
Joined: 11 Jan 2005
Posts: 5
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Hm, OK.
I'll try to make a drawing of my process:
phi1 -> D -> Phi2 -> A -> Phi3 -> E
.....................|................|
......................-> C.......->
.....................|................|
.....................->...............-> B -> Phi4
[dots are instead of spaces, can't turn on HTML mode...]
Control goes from D to A to E, and from D to C to B.
Data goes in all flows, and specifically, the flow from A to B (and D to B) is a data flow only. The data from A is needed in B to control its behaviour (absent data from A is also OK).
Don't know if this helps, but what I don't understand is why the non-existing control flow between A and B is an error? |
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| jmac |
| Posted: Thu Jan 13, 2005 5:56 am Post subject: |
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Jedi Knight
Joined: 27 Jun 2001
Posts: 3081
Location: EmeriCon, LLC
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OK.... Now that I've had my coffee.... I get it,  I read your question wrong.
There is a rule that says you can only flow data between nodes that have a control path. So you do have an illegal diagram.
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John McDonald
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| bjornwall |
| Posted: Thu Jan 13, 2005 6:25 am Post subject: |
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Newbie
Joined: 11 Jan 2005
Posts: 5
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But when is it then legal to have a data flow only, i.e. what's the point of separating data flow from control flow if they can only be used together anyway? Which of course they can, be separated, so I guess I still don't understand why and when they must come in pairs?
/Still confused but now on a higher level  |
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| jmac |
| Posted: Thu Jan 13, 2005 6:47 am Post subject: |
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Jedi Knight
Joined: 27 Jun 2001
Posts: 3081
Location: EmeriCon, LLC
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| bjornwall wrote: |
| But when is it then legal to have a data flow only |
MQWF says never.
To be honest with you, I have never run into a situation where I found I needed to do this (flow Data to an activity where there is no control path). Perhaps if you email me your FDL, I can see what it is you are trying to do.
| bjornwall wrote: |
| what's the point of separating data flow from control flow if they can only be used together anyway? |
To me the point is that it allows me to flow data from Activity n to Activity n+5 without having to send the data thru Activity n+1, n+2 etc.
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John McDonald
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| bjornwall |
| Posted: Thu Jan 13, 2005 7:01 am Post subject: |
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Newbie
Joined: 11 Jan 2005
Posts: 5
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OK, I now see the difference between my two dataflows (I was also confused why one generated an error and not the other), so as you say, flowing data from An to An+9 is OK, but not from An to Bn...
I'll see if I can code a workaround, or I'll mail you.
Thanks for your help! |
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| jmac |
| Posted: Thu Jan 13, 2005 7:05 am Post subject: |
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Jedi Knight
Joined: 27 Jun 2001
Posts: 3081
Location: EmeriCon, LLC
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Good luck... sorry for my initial misdirection... but like I said it was early here
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John McDonald
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