Fstachecki: /* Decision⌘ */

2018-01-30T13:50:36Z

Decision⌘

New page

[[Category:UML Diagrams]]

==Activity Diagram⌘==
[[File:ActivityDiagramENExample.png]]
*Describes the workflow behavior of a system, focuses on flows.
* A Process describes a sequence or flow of Activities in an organization with the objective of carrying out work.
===Activity, Action⌘===
[[File:ActivityAction.png]]

'''Activity'''
*describes a '''sequence of actions''' based on control models and object flow models
*contains edges and activity nodes (e.g. actions)
*represented by a rectangle with rounded corners

'''Action'''
* is a fundamental unit of executable functionality contained within an Activity
* represents a '''single step''' within an activity

===Activity ⌘===
Activity contains '''nodes''':
* Action
* Object
* Control Node
and '''edges''':
*Control Flow
*Object Flow
[[File:ActivityNode.png]]

=====Control Flow⌘=====
[[File:ActivityControlFlow.png]]
* A control flow is an edge that starts an activity node after the previous one is finished
=====Object Flow⌘=====
[[File:ObjectFlow.png|333px]] '''OR''' [[File:ObjectFlow2.png]]

[[File:ObjectFlow3.png]]
* An object flow is an activity edge that can have objects or data passing along it

===Objects⌘===
[[File:ActivityParameter.png]]

*Incoming or outgoing objects are parameters
*Placed (as rectangles) on the border
[[File:ActionPin2.png]]
*Or as small rectangle, called a pin ('''input''' or '''output''')

===Token⌘===
*The semantics of an activity is based on a token flow
*Control tokens and object tokens flow '''between''' nodes '''over''' edges

===Activity Example⌘===
[[File:ActivityExample.png]]

===Initial Node⌘===
[[File:ActivityInitialNode.png]]

* It has outgoing edges but no incoming edges
* An activity may have more than one initial node
** Each generates a concurrent flow
* An initial node can have more than one outgoing edge
** Semantics: a control token at each outgoing edge
* Activity diagrams do not have to have initial nodes
* Notation: a filled circle

===Final Node⌘===
[[File:ActivityFinalNode.png]]

*An activity may have more than one activity final node
*The first one reached stops all flows in the activity
** Regardless of the number of tokens in activity
* At least one incoming edge and no outgoing edges
* If several incoming edges only one must carry a token
* Activity diagrams do not have to have final nodes
* Notation: a filled circle with an outer ring

===Decision⌘===
[[File:ActivityDecision.png]]
* is a control node that chooses between outgoing flows
* One incoming edge and several outgoing edges
* When a token is supplied guards on outgoing edges are evaluated
** Token goes to first true outgoing
* Notation: a rhombus

===Merge⌘===
[[File:ActivityMerge.png|350px]]
* A merge node is a control node that brings together multiple alternate flows
**It is not used to synchronize concurrent flows
*Several incoming edges, one outgoing edge
*Nothing calculated, nothing expected
*Notation: an empty rhombus

===Fork, Join⌘===
[[File:ActivityForkJoin.png|350px]]
*'''Fork''' – one incoming edge and multiple outgoing edges
*'''Join''' – multiple incoming edges and one outgoing edge

===Implicit splitting⌘===
[[File:ImplicitSplitting.png]]

Once action A terminates
* a control token is available at both outgoing edges
* actions B and C start concurrently
===Implicit synchronization⌘===
[[File:ImplicitSynchronization.png]]

Action F doesn't start until tokens are available at both incoming edges - actions D and E have to terminate

===Implicit split/synchronization - object flow⌘===
[[File:ImplicitObjectFlow.png]]

'''AND''' semantics for object flows
*Once action A terminates it provides two object nodes
*Action F doesn't start until object tokens are available at both incoming edges - actions D and E have to terminate

UML Activity Diagram - Revision history

Fstachecki: /* Decision⌘ */