Activity Diagrams

Activity Diagram

How the system accomplishes its goals

Final activity node

Is used to stop all control flows and object flows in an activity.

Initial node

Portrays the beginning of a set of actions or activities.

Control flow

Shows the sequence of execution.

Activity Diagram

a simple and intuitive illustration of what happens in a workflow, what activities can be done in parallel, and whether there are alternative paths through the workflow.

joining

allows process to join multiple processes represented using synchronization bar with 2 or more incoming transitions and 1 outgoing transition waits until all incoming flows are completed before continuing

forking

allows process to split into multiple processes represented using thick horizontal or vertical line with 1 incoming transition and 2 or more outgoing transitions

Activity states

can be further decomposed.

Sequence: Frame

indicates the context of the sequence diagram

Activity: Swim lane

used to break up an activity diagram into rows and columns to assign the individual activities

Activity diagrams contain

Activity states, transitions, and objects

Flow

When an action or activity completes, data passes in to the next action.

rendevous

activity digram- multiple incoming & outgoing transitions

Action states

are atomic and cannot be decomposed

guard condition

boolean condition that determines path represented in square brackets

start/ end state

denoted by a black circle, and a round black circle with a circle around it

Sequence: execution occurrence

long narrow rectangle atop a lifeline -denotes when an object is sending or receiving messages

Fork

may have one incoming transitions and two or more outgoing transitions

Join

may have two or more incoming transitions and one outgoing transition

Control flows

model execution paths

Object flows

model the flow of objects

activity diagram

most often associated with several digrams

Activity: Action

nondecomposable piece of behavior labeled by its name -round rectangle

Sequence: Object

participates in a sequence by sending and/or receiving messages -placed across top of diagram -rectangle

Sequence: Actor

person or system that derives benefits from and is external to the system. placed top of diagram - either stick figure or rectangle with <<actor>> in it

Activity: Initial node

portrays the beginning of a set of actions or activities -solid filled in circle

Activity: Object Node

rep. an object that is connected to a set of object flows labeled by class name - rectangles

Object Nodes

represent the flow of information from one activity to another

Activity: Activity

represents a set of actions labeled by its name - rounded rectangle

object deletion

sequence digram- X shown at the end of an objects lifeline when it is to be deleted

actors

sequence digram- a role that some user or other system plays when interacting with the system actor that initiates the system to far left of system

instance of classes

sequence digram- denoted by a rectangle with object name inside underlined

vertical dimension

sequence digram- time

Activity: object flow

shows flow of an object from one activity (action) to another - dotted line and arrow

Activity: Control flow

shows sequence of execution - line with arrow

branching

specifies alternate paths taken based on boolean expression may have on incoming transition and 2 or more outgoing ones represented as multiple arrows from one activity rectangle with guard condition in brackets or as a decision diamond

Branching

specifies alternate paths taken based on some Boolean expression

swimlane

specifies locus of activities used to partition activity states on activity diagram into groups denoted by solid vertical line

start and stop notation

start marker = filled in circle stop marker = filled in circle with circle around it

substate

state diagram- a state nested inside a state ex: driving a manual car

action

state diagram- instantaneous, describes what the action is

activities in state diagram

takes place while system is in state (takes time), represented by do/ in the state box

Activity Diagrams depict

the sequence of activities.

Activity: Join node

used to bring back together a set of parallel or concurrent flows of activities

Activity: Merge node

used to bring back together different decision paths

sequence diagrams

used to model dynamic aspects of a software system for visualizing how the system runs

Activity

used to represent a set of actions

Activity: Fork node

used to split behavior into a set of parallel or concurrent flows of activities

Activity: final-activity mode

used to stop all control flows and object flows in an activity (action) - filled in circle with outer circling

Activity: Final Flow node

used to stop specific control flow or object flow - circle with an X in it

Notation of Activity Diagrams

• Activities - rectangle with rounded ends; meaningful name; describe some activity e.g. Insert Card • Transitions - arrows with open arrowheads • Start state - black circle • Guard conditions - in square brackets • Decision Points - a diamond • Final state - black circle in white circle.

State Transition Diagrams

• Describe a sequence of transitions from one state to another in a specific class. • The actions that result from a State Change. • Captures all possible responses of a single object to all of the use cases in which it is involved (i.e. whatever that object is used) • Useful for modelling objects which have significant dynamic behaviour.

Specification of the activity diagram

- Stappen in de procedure in de vorm van actions of activiteiten - Transactie van data tussen de actions (noem je flow) - Je kunt zien wat de decisions zijn en wat parallel loopt - Start en einde van een activiteit/action

Guards

A condition that must be true in order for the trigger to cause the transition. These could be: • Pseudo code - "user submits job") • Events - "ready(true)" • An operation call - "execute()" • A calculation - "X > 5.54" • A time - "10 min" • Complex Predicate Logic

Guard (condition)

A condition that must be true to pass the flow - Specify the condition of outgoing flows with a decision point - Guards are expressed as [description] - Guards CAN NOT overlap -Having guard flows without decision points is allowed - Having flows without guards is allowed - If the decision point has an outcoming flow, having a guard is MANDATORY.

Joins

All incoming actions must finish before proceeding - A join may have 2 or more incoming flows and has 1 going out - Sychronization point for parallel flows - The outgoing flows is ONLY triggered when ALL the parallel flows are at the join point.

Sequence: Object destruction

An X is placed at the end of an objects lifeline to show that it is going out of existance

Pins

De input of output van een actie >[ ]<. - De 'Recieve signal node' (in, x[]) kan ook een initial node zijn. - Deze nodes laten zien dat een object beschikbaar is bij een bepaalde tijd of activiteit.

Expansion region

Dit ziet er altijd uit als 4 kleine blokjes. De acties moeten gedaan worden op alle items die onder deze group vallen

Join node

Is used to bring back together a set of parallel or concurrent flows of activities

Merge node

Is used to bring back together different decision paths that were created using a decision node

Decision node

Is used to represent a test condition to ensure that the control or object flow only goes down one path

Fork node

Is used to split behavior into a set of parallel or concurrent flows of activities

Final flow node

Is used to stop a specific control or object flow

Forks and Joins

Parallel actions

state

Represented by rounded rectangle with Object name inside

Object flow

Shows the flow of an object from one activity to another activity. Could also include actions

Actions

Steps in the process, primary activity nodes. - Its execution presents a small computation task - Its execution results in a change of the systems state - it execution extracts information from the system - actions are atomic (ondeelbaar) and CANNOT be decomposed - The execution of the action state is not interrupted

Control Nodes

There are 7 types!

Branching

This specifies an alternative path taken because of the guard condition - Must have 1 incoming flow and CAN have more than 2 outgoing

UML

Unified Modeling Language general-purpose, developmental modeling language in software engineering standard way to visualize a system design

Call activity node

Upside down pitchfork - Een eigen diagrammetje waar in de informatie uitgebreider (kleinere stapjes) is - Een node die een activiteit laat zien en gebruikt door middel van zijn naam - Is reusable

Swimlane

Used to break up an activity diagram into rows and columns to assign the individual activities (or actions) to the individuals or objects that are responsible for executing the activity

Object node

Vierkantje - Heeft belangrijke data en laat zien met welke acties die interact. - Een object dat gespecificeerd word door een object node, kan worden gecreeerd, geconsumeerd of gemodificeerd door de actions in zijn omgeving. - Heeft vaak een note erbij

Swim Lanes

Wanneer de activities meerdere participants hebben laat dit zien welke participant verantwoordelijk is. -Elke swim lane heeft een unieke naam die een real world entity of software object represent

Fork

When a flow breaks up into multiple flows - Has one incoming and may have 2 or more going out - Each flow represents an independent flow of data - The actions of each of the outgoing flows are at the same time

Time events

Zandloper: Moet text hebben die verteld wat het doet, is een waiting period (wacht 5 minuten) OF een INITIAL NODE (dan is het een periodieke actie, elke 5 minuten)

Action

a simple, nondecomposable piece of behavior.

concurrency

activity digram- fork, rendevous, join

join

activity digram- multiple incoming transitions and one outgoing transition

fork

activity digram- one incoming transition & multiple outgoing transitions

swimlanes

activity digram- used to show partition of activities

Sequence: Lifeline

denotes the life of an object during a sequence -contains an X at the point at which the class no longer interacts - dotted line

activity diagram

describes how activities are coordinated records dependencies b/w acitvities represents workflow of process

state diagram

describes the behaviour of a system, some part of a system, or an individual object

Properties of swimlane

each has name unique within diagram may represent some real-world entity may be implemented by one or more classes each activity belongs to only ONE swimlane, but transitions may cross swimlanes

transition

represents a change of state in response to an event, label is event that causes the change of state

Sequence: Guard Condition

represents a test that must be met for the message to be sent

activity

represents high level action or process can be business process or abstract computing process represented by a rounded rectangle

messages

sequence digram- can be actor to actor or actor to object arrow pointing between with label

opt

sequence digram- combined fragment: subsequence of a special interaction shown in a box may or may not occur

loop

sequence digram- iteration over objects # of iterations indicated by min..max syntax

vertical line attached to actors and objects

sequence digram- lifeline turns into activation box

Activity: decision node

used to represent a test condition to ensure that the control flow or obj flow only goes down one path - diamond with 2 paths labeling each criteria

Object Node

used to represent an object that is connected to a set of object flows

transitions

when action or activity of state completes, flow of control passes to next action or activity state shown by arrow flow of control has start and end

State

• A state is a condition during the life of an object or an interaction, during which it satisfies: some condition; performs some action; or waits for some events. • States are determined by the value of an objects attributes. An assignments state could perhaps be deducted by examining start and end date and comparing it to current date.

Sub-State Fragments

• A state may be divided into regions containing sub-states that exist and excuse concurrently. • E.g. "Applying breaks" could be a state and within this state, the front and rear breaks will be operating simultaneously and independently.

Activity Diagrams

• Describe a sequence of transitions/actions from one activity to another to fulfil a certain task • The different actions may involve different object and may be conditional. • Complements a state diagram as it focuses on the flow of activity to achieve a certain task which may involve different objects. • To determine what an object does during states of a state diagram, and what a collection of objects do through a whole use case.

Synchronisation Bars

• Drawn as shot, heavy horizontal or vertical bar. • Denotes the forking and subsequent synchronisation of the flow of control to potentially parallel activities. • Fork is used when one arrow goes in and numerous leaves. Join is used when numerous arrows go in but only one leaves.

Notation of State Diagrams

• Initial state - round black circle • Other states - rectangles with rounded corners showing name of state e.g. happy • Final state - a "bulls eye" circle ( black circle surrounded by white circle). This shows end of the transition, it is not a state in its own right. • Transitions - arrows - optionally with constraints/guard conditions.

Why is an objects state important?

• It could espied to messages differently depending on its state • E.g. in an Aircraft Flight Control System, it would react different to an event like Engine Failure when the state is inflight, taxiing or static.

Swim Lane Notation

• Swim lanes can group actions by: class, business unit, person etc. • Can be either horizontal or vertical • E.g. swim lanes could be Customer, Sales, Stockroom

Purpose of Activity Diagrams

• To model a task (for example in business modelling) • To describe a function of a system represented by a use case) • To describe the logic of an operation • To describe any flow of events