workflow in temporal state machine v1

Basic
B i COSA Workflow Example
W kfl E l
in a Temporal State Machine

GORDON MORRISON
GORDON.MORRISON@VSMERLOT.COM

www.vsmerlot.com 7/11/2010

What is workflow?

 Workflow is understanding the rules and steps that
g p
define the process of work being performed
 Workflow rules require understanding the temporal
relationships of binary states, their true or false
behaviors and their respective true or false next state
transitions.
transitions
 Workflow requires the proper placement of detail in
abstraction.
abstraction


Examples

 Processing any event
g y
 Processing documents, languages, or databases
 User interactions with systems
y


Things common to workflow

 All have a temporal basis
p
 All are based on rules that have one or more steps
 All have rules/steps that consist of states that have
/ p
true and false behaviors
 Some states do nothing but transition to another
state
 In temporal logic rules/steps/states do one thing
 It’s done well
 It’s coherent


Temporal State Machine

 Temporal State Machine
 While (Engine) {
 If(this->table(iTime).f_State())
 This->table(iTime).TrueBehavior()
T TrueTrace = Thi
T This->table(iTime).trace;
bl (iTi )
 iTime = table(iTime).NextTrueTime;
 Else
 This->table(iTime).FalseBehavior();
 FalseTrace = This->table(iTime).trace;
 iTime = table(iTime).NextFalseTime;
}
 }
 Table is defined on the next slide


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 The temporal state machine refers to this logic table,
p g ,
the seven columns are:
 Rule name or step displacement
 Function testing state
i i
 True behavior
 Next true behavior to execute
 False behavior
 Next false behavior to execute
 Trace


A Workflow Example

 RULE TEST STATE TRUE B NEXT T FALSE B NEXT F TRACE
 rStateMach,
rStateMach f_Initial,
f Initial pCreate,
pCreate +1
+1, Ignore,
Ignore rError,
rError 1000
 +1, f_Status, pCreated, rReady, pNotCreated, rError, 1001
 rReady, f_Approved, pApproved, rAction, Ignore, +1, 2000
 +1, f_Rejected, pRejected, rDone, Ignore, +2, 2001
 +2 f_Cancelled,
f Cancelled pCanceled, Done
pCanceled rDone, Igno e
Ignore, rError,
E o 2002
 rAction, f_Act1, … 4000

 rDone, f_Done, … 9000
 rError, f_Error, …
f 9086


State Machine Interfaces

 temporalMachine.approve;
p pp ;
 Moves the temporal pointer

 temporalMachine.cancelled;
 Moves the temporal pointer to canceled

 Tests the status

 Returns a Boolean result


Rules

 Rules define the workflow
 Rules are defined in the state machine workflow
table
 Each row requires that each column have an entry
 Every state has a true and false behavior
 Every state h a true and f l next b h i
has d false behavior
 Guards are defined as complete rules
 L i fl
Logic-flow is separate from d t fl
i t f data-flow


Rules are Complete

 Rules consist of one or more steps p
 Each step is a row in the logic table

 Rules are only entered at their beginning
 Rules allow looping within the rule
 Rules can exit from anywhere within the rule
 Rules are not nested
 Rules are located in time with the workflow
 When
Wh an action i approved
i is d
 Next rule or step is ready for test


Nested Temporal State Engines

 Another Temporal Engine can be called from a rule
p g
 Another object can be created from a rule
 Another thread can be created from a rule


The Temporal Pointer

 Managed by the Temporal Engine:
g y p g
 Can be set to the zero rule on each entry

 Can be left at the last rule or step used

 C
Can be provided as an argument when the T
b id d h h Temporal E i i
l Engine is
called or reentered


Trace / Audit is Inherent

 The Temporal Engine Provides a:
p g
 True trace for every state/step

 False trace for every state/step

 The trace can always be on
 Or the trace can be dynamically bound
 Turned on or turned off at runtime
d d ff i


Breaking the Time Barrier


A Temporal Understanding

Question: What are the five most importing things in
creating quality software?
i li f
 1) Temporal Logic
 Reduced complexity
 2) Temporal Logic
 Improved quality
 3) Temporal L i
)T l Logic
 Greater performance
 4) Detail
 The devil lives here don’t get carried away with abstraction
 5) Abstraction
 It s
It’s important but to much has caused many a project to fail


workflow in temporal state machine v1

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workflow in temporal state machine v1