1. s
re for developer
Softwar e architectu
What is software What is therole of How do you define How do you share How do you deliver
architecture? a software architect? software architecture? software architecture? software architecture?
Where do you start?

2. simon.brown@codingthearchitecture.com
@simonbrown on Twitter

3. Software Architecture for Developers (.com)
What is software
architecture?
What is the role of
a software architect?
How do you define
software architecture?
How do you share
software architecture?
How do you deliver
software architecture?

4. What is software What is therole of How do you define How do you share How do you deliver
architecture? a software architect? software architecture? software architecture? software architecture?
How do you take a system vision
through to a software design?

5. What is software
architecture?

6. What is architecture?
Requirements
Architecture
Structure Design Framework Foundations

7. Application architecture
ecture
r chit
ti on a ware
Ap plica he soft elive
r
t to d
ides d
prov n eede
ati ons value
f ound iness
bus
Requirements
An application
Classes &
Design Patterns Frameworks Libraries
Components

8. System architecture
vides
r e pro e
hitectu r dwar
m arc n d ha
S yste tw are a elive
r
sof to d
the ation
s
fo und value
bus iness
Requirements
A system
Services & Interoperability
Software Hardware
Subsystems & Integration

9. Enterprise Architecture
Technology and business strategy across organisations and organisational units.
{
System Architecture
Software and infrastructure architecture
for an end-to-end system.
Application
Architecture
Software architecture for an
We call this application, sub-system or
component.
software
architecture
/// <summary>
/// Represents the behaviour behind the ...
/// </summary>
public class SomeWizard : AbstractWizard
{
private DomainObject _object;
private WizardPage _page;
private WizardController _controller;
public SomeWizard()
{
}
...
}

10. Software architecture introduces
structure and guidelines
into a software system, leading to
consistency and clarity

11. What is the role of a
software architect?

12. The role of a software architect
Management of Ownership of
Architecture
non-functional the bigger Leadership
definition
requirements picture
Technology Architecture Coaching and Quality
selection evaluation mentoring assurance
Design,
Architecture
development
collaboration
and testing
Architecture Definition Architecture Delivery

13. http://www.infoq.com/articles/brown-are-you-a-software-architect

14. How do you define
software architecture?

15. Every system has an
architecture, but not every
architecture is defined
bout
h ink a
ople t on’t
!
e pe o me d
Som re, s
it ectu
arch

16. Goal
What drives architecture?
Options
s
nt
ai
tr
ns
l Co
u ra
ct
ite
ch
Ar e s
pl
ci
in
l Pr
u ra
ct
ite
ch
Ar
s
n - nt
n o me
l & ire
n a qu
tio re
n c al
Reality
Fu ion
n ct
fu

17. Functional
requirements can influence
the architecture
(understand and challenge them if necessary)
ally is
il re
Th e dev e tail!
in t he d

18. How many elephants did
you see at the zoo?
How many non-elephants?
Kevlin Henney

19. Non-functional requirements
What non-functional requirements
(e.g. “-ilities”) have you encountered
in software development?

20. Performance Flexibility
✓
Scalability Extensibility
✓
Availability Maintainability
Security ✓
Interoperability
Disaster Recovery Legal
Accessibility ✓
Regulatory
Monitoring Compliance
Management i18n
✓
Auditability L10n
... ...
Runtime Non-runtime

21. Performance is about how
fast something is

22. Response Latency and
time throughput
a pps,
web
le to ems,
licab g syst
App s sagin
s , me e tc...
UI As,
SO

23. Scalability is about
doing more
(more requests, more data,
more users, more messages, ...)
ently
inher
lity is rrency
Sc alabi oncu
c
ab out

24. Vertical Horizontal
scalability scalability
(scale-up) (scale-out)
s
o nent
omp
A ll c e ntly;
iffer
sc ale d easy
- up is
s cale

25. Availability is about
uptime
9 .99%,
. 9%, 9
99 %, 99 x 7, ..
.
%, 24
9 9.999

26. Low High
availability availability
(single points of failure) (redundancy)
s
o nent
c omp abilit
y
All t avail
f eren s
have dif r istic
acte
char

27. Understand how to
capture them
tions e
ques
your u dienc
Vary your a
n
ing o
de pend

28. Understand how to
refine them
ific,
Spec ,
RT: vable
SMA A chie
sur able, imely
Mea T
nt &
R eleva

29. Understand how to
challenge them
u
sur e yo
u
Ar e yo
eed
?
that
n

30. Understand how they
influence
your architecture l
tiona
o n- func plex
!
Some n e com
t s ar
r emen
requi

31. Learn about and understand
the non-functional
requirements in order to
build sufficient foundations

32. Software lives in the real world,
and the real world has
constraints

33. Constraints
What constraints might
affect software architecture?
What constraints have you seen in your
own organisations?
Are all constraints negative?

34. Scope
Cheap + Quickly = Feature-light
Feature-rich + Quickly = Expensive
Cost Time
Time & budget

35. Technology
(e.g. approved technology lists, existing
licenses, interoperability,
product maturity, common protocols,
local standards, public standards,
open source policies/licenses,
vendor “relationships”, etc)

36. Resources
skills
&
(e.g. team size, lead time, future
availability, training, specialists, etc)

37. Other
(e.g. legal/compliance, tactical vs
strategic imperatives, existing
systems, company politics, past
failures, internal intellectual
s ...
tacle
property, etc) will be obs e them!
m
T here v erco
u st o
yo u m

38. Beware that constraints can
drive the architecture more
than the requirements

39. Understand what the
constraints are, why they are
imposed, how they affect the
architecture and how you will
work with them

40. Architectural
principles
are the things you want to adopt
duce
intro
e lp to larit
y
Th ey h y and c
s tenc
c onsi

41. Principles
What architectural principles have
you seen applied to software
development projects?
What principles have you seen in your own projects?
Were the principles beneficial?
What impact did the principles have?

42. Principles are great,
but make sure they’re
realistic and don’t have a
massive negative impact!

43. Goal
How do you get to the goal?
Options
s
nt
ai
tr
ns
l Co
u ra
ct
ite
ch
Ar e s
pl
ci
in
l Pr
u ra
ct
ite
ch
Ar
s
n - nt
n o me
l & ire
n a qu
tio re
n c al
Reality
Fu ion
n ct
fu

44. Start analysing
coding
or start ?
para
ly sis &
r
s
alysi acto
An r distr
ref acto h ba
d
t
ar e bo

45. Bo xes & l ines
is
Object or iented analys
n
Break the problem dow and de sign (OOAD
)
into components
and services
ty
Class Responsibili
)
Collaboration (CRC
ices
What comp onents/serv
?
do we need to do X ware
a soft is
sing nts
omp
o pone
Dec com ating
talk i nto
H ow do they sys tem estim
l for
to each oth
er? u sefu

46. ems) Standard (
(syst containers
)
angle
Wide
ld
s hou
Start with the
pict ure t
Eve ry n t par
big picture Mac fere
ro a dif tory
t l
(cella e same s
ofsses)
th
Telephoto (components)

47. UML
eed a e
on’t n e ctur
Y ou d r chit
do a
to ol to desig
n
and
Whiteboard? UML tool?

48. Systems
Internet Banking System Administration System
Allows customers to interact
Allows call centre staff to
securely via the web.
undertake administrative actions.
s
New System
tems
Existing Sys
Banking System
Single point of truth for all
customer data.
Contains all core banking logic.

49. Containers External web server
Web server
Allows customers to interact
Internal web server
securely via the web. Allows call centre staff to
Allow call centre staff to undertake administrative actions.
undertake administrative actions.
IIS
IIS
mmunication
Windows Co
Foundation
Application server
Orchestrates user interaction
across big legacy system.
IIS
rotocol
XML/TCP p
SQL
Database
e app,
Stores customer information Banking system andalon
er, st b ase,
ervfor all ice, data
related to Internet Banking.
Retains audit logs.
eb s
Single point of truth
Wdata. erv i n, ...
Stores help text, banners and customer
Contains all indo
ws S SB, plug
other commentary.
Wcore banking er, E
logic.
serv
SQL Server
app UNIX

50. mponents
Web server
Co
r
Appli cation serve
Authentication Service
Login.
Banking Service Authorise transaction.
Logout.
Get accounts. Reset credentials.
Get statement. Lock account. WCF service
Get/create/edit/delete
recipients.
Make payments. WCF service
r
Service Laye
Data Layer
Audit Service
Banking System Facade Write audit log entry.
Get audit log entries for
Single point of truth for all
customer.
customer data.
Contains all core banking logic.
C#
C#
Database
Banking System

51. Classes
e
Banking S ystem Facad
BankingSystemFacade
<<abstract>>
Get accounts. Transaction
Get statement. Creates Execute transaction.
Get/create/edit/delete Audit transaction.
recipients.
Make payments.
of
Uses Is made up
<abstract>
<abstract>
BankingSystemInterface Response
Request Parse XML response into domain
Convert request to XML. object(s).
Initiate connection.
Execute transaction.
e
d us
Close transaction.
l
cou ,
You ards
RC c ...
UM L, C ,
oard
a w hiteb
Banking system

52. In terfaces
External web server
to Application server
Technology, format & protocol Internal web server
Service-level agreements
to Application server
Ownership
Technology, format & protocol
Release cycle & versioning
Service-level agreements
etc...
Ownership
Release cycle & versioning
etc...
Application server
to Database
Technology, format & protocol
Service-level agreements Application server
Ownership to Banking System
Release cycle & versioning Technology, format & protocol
etc... Service-level agreements
ically
r e typ y
es a
Ownership
a c o f an
terf arts
Release cycle & versioning
In p e
est ctur
etc...
ki e
th e ris r chit
w are a
soft

53. Use stories/use cases to
walkthrough
and test your design

54. Your experience should
guide you rather than
constrain you
,
re great
a s es a o use
atab eed t
D
do n’t n l utio
n
u y so
bu t yo r
o r eve
o ne f

55. Don’t blindly focus on the
code; always ask what the
major forces are on the
system and how your
architecture resolves them
e
ee th
to s
back
Step e
big pi ctur

59. How do you share
software architecture?

60. Current Development Team Business Sponsors Future Development Team
Your system
Database Administrators Operations/Support Staff
e
ectur
r chit
w are a for
Soft pla tfor
m
ocia
l!
is a .. be s
t ion .
ersa
conv
Other Teams Security Team Compliance and Audit

61. It looks like there are multiple architectural layers.
There are many libraries in the middle-tier; are they components?
There’s a web application.
Lots of C# code!
There are some WCF service references.

62. Process View Non-functional View
Context Functional View Does the system implement
Are there any significant non-
What is this all about? What does the system do? functional requirements influencing
business processes?
the architecture?
Architectural Architectural
Logical View Interface View
Constraints Principles What does the big picture look like Are there internal or external
Are there any constraints Are there any principles influencing and how is the system structured? system interfaces?
influencing the architecture? the architecture?
Design View Infrastructure View Deployment View Operational View
How will the system components be
Is it clear how system components What does the target deployment How will people operate and
deployed onto the target
should be implemented? environment look like? support the system?
infrastructure?
Architecture
Security View Data View Technology Selection
How is security handled across all How is data managed, archived, What led to the selection of the Justification
tiers? backed-up, etc? technologies in use? Does the chosen architecture
“work”?

63. Abstract
Whiteboard
Software Review Wiki
Ar C Cstandards
chitecture oding onversation /*
D t
ocumenDesign conformance * Pair
v0.2 Test coverage * Programming
Thread safety */
n
De l egatio Security
/** Logging
/// Represents the behaviour behind the user tion handling chitecture e(!a
* Reference Ar
/// <summary>
/// </summary>
Excepregistration page. whil ngry) {
public class RegistrationWizard : AbstractWizard nsibility
{ hote Yo
Ex r
* @autstrationCandidate; u pair(you);
*/
private RegistrationCandidate _regi
privat Under;standing
e RegistrationWizardPage _page;
}
Morale
private RegistrationWizardController _controller
Specific

64. How do you deliver
software architecture?

65. How much architecture
do you need to do?
This much?
Waterfall RUP Agile
This much?

66. You need to define
“just enough”
architecture

67. What is architecturally
significant?
C ostly to cha
nge
Complex and risky New

68. Does your architecture
work?
ng
Satisfies th
e
Fou ndations for Platform for solvi
vers blem
arch itectural dri the code the business pro

69. Concrete
experiments
Requirements
A system
/
type
p roto
wa way pt o
r
thro once
Foundations A
of of c code
pro ction
p rodu

70. Let’s wrap up...

71. What is software What is therole of How do you define How do you share How do you deliver
architecture? a software architect? software architecture? software architecture? software architecture?
nts
Requiremen ts, constrai
and principles drive ose the pro
blem
ures Decomp
softwa re architect
How dosyou take a system visionshould
ms, containe
r ,
Syste ure
through
sse s to a software very pict
E design?
com ponents, cla a different p
art
tell
and interfaces y
of th e same stor
t
Write code and tes
your architecture
ible
as e arly as poss

72. simon.brown@codingthearchitecture.com
@simonbrown on Twitter
!
Th anks
http://www.codingthearchitecture.com
s
re for developer
Softwar e architectu