ArchiMate and general system theory

Transcription

ArchiMate and general system theory
Find this and related slide shows on the TOGAF with ArchiMate page,
at http://grahamberrisford.com
Avancier
ArchiMate and TOGAF
Core concepts
Symbols (boxes & lines)
Concept framework
1. The Generic Meta Model
2. The Enterprise Architecture layers
3. Analysis of diagram meanings
4. Alignment with General System Theory
EA models the enterprise as a
system that is stateful and eventdriven.
System elements are
interrelated.
Events trigger changes to system
state and/or the provision of
services to external entities.
Relations
Diagram types
Concept Framework
Aligning the generic meta model with
General System Theory (GST)
Including diagrams and definitions edited from the ArchiMate 2.1 standard.
Copyright © The Open Group, All Rights Reserved.
ArchiMate is a registered trademark of The Open Group.
Training at http://avancier.website
Where to look for inspiration?
Avancier
► ArchiMate looks to natural language
■ subject = active structure element
■ verb = behavior element
■ object = passive structure.
Object
Verb
Subject
Service
Interface
Process
Component
► Natural language is malleable
■ The dog <bit the tail of> itself
► It is arguable that general system
theory provides a more secure
platform for the generic meta model
Training at http://avancier.website
State
What is an activity system?
Avancier
► Generally speaking, an activity system is a set of
■
■
■
■
components that perform roles in processes
to produce desired effects
by maintaining system state and/or
producing outputs from inputs
Some activity systems
Human activity system
Computer activity system
Biological entity
Other machine or
technology
Training at http://avancier.website
Five tenets of general system theory
1 A system description is abstraction.
2 A system is logically bounded within its
environment
3 A system interacts with its environment via
inputs and outputs
4 Holism: a system’s components are related in
structures and interact in processes
5 A system processes information and maintains
an internal state
“real systems are open to, and interact with, their environments,
the arrangement of and relations between the parts which connect them
into a whole (cf. holism).
system-environment boundary, input, output, process, state,
hierarchy, goal-directedness and information.
a system is independent of the concrete substance of the elements”
Principia Cybernetica
Training at http://avancier.website
Avancier
Environment
Desired effects on
external entities and activities
Inputs
Outputs
Processes
Components
State
System
General system theory concepts - used in the BCS ESA RM
Avancier
1 A system description is abstraction.
2 A system is logically bounded
within its environment
3 A system interacts with its environment
via inputs and outputs
Service
5 A system processes
information and maintains an
internal state
Interface
System
State
Process
Component
Environment
4 Holism: a system’s components are related in
structures and interact in processes
“real systems are open to, and interact with, their environments,
the arrangement of and relations between the parts which connect them into a whole (cf. holism).
system-environment boundary, input, output, process, state, hierarchy, goal-directedness and information.
a system is independent of the concrete substance of the elements”
Training at http://avancier.website
A generalisation of the four system elements
► Structure and Behaviour views. Internal and External views
ArchiMate/
BCS grid
Behavioural view
What a system does
Structural view
What a system is made of
Event / Service
External view
Interface
encapsulates the processing of
what external
a service portfolio accessible by
a discrete event or service
entities see
clients
request.
Process
Internal view
one or more activities that
the workings
respond to an event or meet a
of the system
service request.
Component / Role
a subsystem that
performs process steps.
Training at http://avancier.website
Avancier
A generic meta model
Avancier
► ArchiMate assumes construction and realisation processes
ArchiMate/B
CS grid
External view
what external
entities see
Internal view
the workings of
the system
Behavioural view
What a system does
Realisation
Structural view
What a system is made of
Event/
Service
Interface
Process
Component
Construction
Training at http://avancier.website
Behavioural elements v. Structural elements
Avancier
“It is the pervading law of all things organic and inorganic, of all things physical and
metaphysical, of all things human and all things super-human, of all true manifestations
of the head, of the heart, of the soul, that the life is recognizable in its expression, that
form ever follows function. This is the law.” American architect Louis Sullivan, 1896.
►
►
►
►
has start and end points
describe what a system does
have a time dimension.
usually repeated, and
sometimes cyclical.
Event/
Service
Interface
System
Process
Component
Behavior
Active Structure
► no start and end points,
► describe what a system is
made of
► are addressable.
► perform processes
Usually, persistent component/roles outlive transient processes.
This is not always true, but it is a helpful way of thinking about the structure/behaviour distinction.
Training at http://avancier.website
A system is encapsulated in an environment
Avancier
Environment
Hot dinners
Cold snacks
Drinks
Order
Cook
Serve
Event/
Service
Interface
System
Process
Component
Behavior
Active Structure
Training at http://avancier.website
A la carte menu.
Table d’hote menu
Today’s specials.
Waiter
Chef
Oven
Where is the system’s state?
Avancier
► The system’s information state
► (its memory, which is updated and referred to by processes)
► contains structured business data objects
Object: an item
or structure
that is used,
moved or made
by processes
Event/
Service
Object
Passive Structure
Interface
System
Process
Component
Behavior
Active Structure
A system processes information
and maintains an internal state
Training at http://avancier.website
System elements are recursive
Avancier
Environment
A system description is
abstraction.
Event/
Service
Object
Passive Structure
Interface
System
Process
Component
Behavior
Active Structure
Training at http://avancier.website
5 system description entities as Avancier defines them
Service: what a client can request
to process a specific event or
deliver a specific result
Object: an
item or
structure that is
used, moved or
made by
processes
Interface: a service portfolio
accessible to clients
Event/
Service
Object
Passive Structure
Interface
System
Process
Component
Behavior
Active Structure
Process: a sequence of activities Component: a subsystem that
that respond to an event or meet a performs process steps.
service request.
Training at http://avancier.website
Avancier
The ArchiMate generic meta model mapped to architecture layers
Passive structural
elements
Business
Applications
Infrastructure
Behavioral elements
Avancier
Active structural elements
Business
Service
Business
Interface
Business
Process
Business
Role
App
Service
App
Interface
App
Function
App
Component
Infrastructure
Service
Infrastructure
Interface
Infrastructure
Function
(inc. Sys Software
& Device)
Business
Object
Data
Object
Artifact
Training at http://avancier.website
Node
Business
Actor
Beware that “interface” can be interpreted two ways
Avancier
► as a passive structural element – e.g. a menu.
► as an active structural element via which services are invoked – e.g. a
waiter.
External
Service
Interface
menu?
waiter?
Process
Component
Behavior
Active Structure
Internal
► The latter is a special kind of component, a facade component, which
shows an interface definition to service consumers.
Training at http://avancier.website
Interface as a passive structural element
Behaviour
what the system does
External Service: operation clients can
request to deliver a result
what external
entities
Service
see
Internal
Process
the workings
of the Process: performed step by step
system
to meet service requests
Avancier
Structure
what the system is made of
Interface: service portfolio Purely descriptive of
services offered
accessible by clients.
Interface
Component
Component: subsystem
that perform processes.
Training at http://avancier.website
The menu
The waiter who
presents the menu
Interface as an active structural element
Behaviour
what the system does
External Service: operation clients can
request to deliver a result
what external
entities
Service
see
Internal
Process
the workings
of the Process: performed step by step
system
to meet service requests
Avancier
Structure
what the system is made of
A façade
giving
Interface: service portfolio component,
access to services
accessible by clients.
Interface
Component
The waiter* who
presents the menu
The chef who
processes the order
Component: subsystem
that perform processes.
* Not the waiter actor. Rather, that part of the waiter role that is merely a façade.
The waiter actor (a person) can play that and play other roles
Training at http://avancier.website
Aside: further reading
Avancier
► For formal yet natural language description of business rules, then
■ try Semantics of Business Vocabulary and Business Rules (SBVR)
■ a standard of the Object Management Group (OMG)
■ part of their Model Driven Architecture (MDA).
Perhaps also ORM?
http://www.orm.net/pdf/ORM2_TechReport2.pdf
► For an exploration of system theory and how it differs from systems
thinking
■ See Systems Theory for Architects at avancier.website
Training at http://avancier.website
Architecture frameworks
► Avancier Methods
are useful with all
architecture
frameworks that share
similar domains and
entities
Avancier
BCS E&SA
reference model
ArchiMate
Language
Framework
► http://avancier.co.uk
TOGAF
The Open Group
Avancier
Methods
CSC’s domains of
change (POLDAT)
IBM’s view EA
EA as Strategy”
MIT
Training at http://avancier.website