Ivasiletc at 10:14, 28 April 2021

2021-04-28T10:14:46Z

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[[Category:Private]]
[[Category:OCUP2]]
==Module 2. Activity Diagram⌘==
===References⌘===
* Filip Stachecki, Concurrency in UML, White Paper, March 2014
===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 ⌘===
[[File:ActivityNodeEdge.png]]

Activity contains nodes and edges.
====Activity Node ⌘====
[[File:ActivityNodeMetamodel.png]]

Subtypes of Activity Node

[[File:ActivityNode.png]]

====Activity Edge⌘====
[[File:ActivityEdge.png]]
* The edges of an activity
* Denoted by a straight line with an open arrowhead
=====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:ObjectNodeMetaModel.png]]
* Object Node is used to describe object flow within an activity
* Notation: rectangle
====Pin or Parameter⌘====
'''Parameter'''<br/>
[[File:ActivityParameter.png]]
*Incoming or outgoing objects connected to an activity are parameters
*Placed (as rectangles) on the border
<br/>'''Pin'''<br/>
[[File:ActionPin2.png]]
*Or as small rectangle, called a pin ('''input''' or '''output''') connected to actions
=====Pin or Parameter example⌘=====
[[File:ClipCapIt-141105-113509.PNG]]
=====Stream and exception parameter⌘=====
[[File:ClipCapIt-150904-122128.PNG]]
* Streaming parameters allow values to be passed into and out of a Behavior execution any time during its course, rather than just on invocation and completion.
* Exception Parameter (output only) is annotated with a small triangle.

===Token⌘===
*The semantics of an activity is based on a token flow
*Control tokens and object tokens flow '''between''' nodes '''over''' edges
* An '''object token''' with no value in it is called a '''null token'''.
* A null token can be passed along an object flow and invoke behavior without passing any value.

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

===Control Nodes⌘===
[[File:ClipCapIt-141105-111637.PNG]]
* Control Node is used to manage the flow of tokens between other nodes in an Activity.
====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

====Activity 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
====Flow Final Node⌘====
[[File:ClipCapIt-150923-231210.PNG]]
* '''A Flow Final Node''' is a Final Node that terminates a flow by consuming the tokens offered to it.

====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
* incoming to and outgoing from a Merge must be either all Object Flows or all Control Flows.
=====Decision example⌘=====
[[File:ClipCapIt-141104-174135.PNG]]

====Fork, Join⌘====
[[File:ClipCapIt-141104-174247.PNG]]
*'''Fork''' – one incoming edge and multiple outgoing edges
*'''Join''' – multiple incoming edges and one outgoing edge

=====Join with Object Flow⌘=====
[[File:ClipCapIt-141105-105041.PNG]]
* If one of the incoming flows of a Join Node is an Object Flow, then its outgoing flow must be an Object Flow.
=====Fork with Object Flow⌘=====
[[File:ClipCapIt-141105-105751.PNG]]
* The Activity Edges incoming to and outgoing from a Fork Node must be either all Object Flows or all Control Flows.

====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
====Fork/Join and Merge mix⌘====
[[File:ClipCapIt-150826-111522.PNG]]

===localPrecondition and localPostcondition⌘===
[[File:ClipCapIt-141104-083658.PNG]]
* localPrecondition for an Action is constraint that should hold when an execution of an Action starts
* localPostcondition for an Action is constraint that should hold when an execution of an Action completes
===Call Actions⌘===
====Call Behavior Action⌘====
[[File:ClipCapIt-141104-160811.PNG]]
* '''Call Behavior Action''' invokes a Behavior directly

====Call Operation Action⌘====
[[File:ClipCapIt-161003-162232.PNG]]
* '''Call Operation Action''' transmits an Operation call request message to the target object

===Send Actions⌘===
[[File:ClipCapIt-141104-160925.PNG]]
* '''Send Signal Action''' creates a Signal instance and transmits the instance to the object given on its target
* '''Broadcast Signal Action''' transmits the signal instance to all available target objects in the system.
* '''Send Object Action''' transmits any kind of object to the object given on its target

===Accept Event Actions⌘===
[[File:ClipCapIt-141104-155216.PNG]]
* Accept Event Action waits for a specific event to occur.
====Accept Event Actions examples⌘====
[[File:ClipCapIt-141104-155340.PNG]]
===Weight⌘===
[[File:ClipCapIt-141128-145321.PNG]]
* Weight specifies minimum number of tokens that must traverse the Activity Edge at the same time.
* Once the minimum number of tokens are offered, all the tokens offered by the source are offered to the target all at once.
* If no weight is specified, this is equivalent to specifying a constant value of 1.
===Activity/Action Meta Model⌘===
[[File:ActivityMetaModellFull.png]]
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OCUP2F 06 Activity Diagram - Revision history

Ivasiletc at 10:14, 28 April 2021