There are some recurring themes in Domain-Driven Design applications, and distant domains show more similarities that differences, especially when you start taking into account peculiarities of specific Bounded Contexts. This is where a different type of design could happen.

1. Why
do
all
my
DDD
apps
look
the
same?
@ziobrando

2. About
me
In
the
IT
field
since
ZX
Spectrum
Generally
in
large
scale
projects
(I
might
be
biased)
Freelance
consultant:
NotOnlyCode
Trainer
(Freelance
&
Skills
MaDer)
Technical
Writer
Blogger:
h=p://ziobrando.blogspot.com
TwiDer:
@ziobrando
My
e-­‐mail:
alberto.brandolini@gmail.com

3. What
I
do
9%
11%
12%
31%
38%
Agile
processes
Domain-­‐Driven
Design
Efficiency
&
Management
Architecture
Funny
clown

5. Some
things
work
pre=y
well
Focusing on Core Domain

7. Core Domain

8. Core
Domain
Nothing
less
than
your
best
here.

9. Some
things
work
pre=y
well
Focusing on Core Domain
Software Development as a Learning
Process

10. Ignorance
is
the
single
greatest
impediment
to
throughput
Dan
North

11. 100 1 2 3 4 5 6 7 8 9
100%
0
10%
20%
30%
40%
50%
60%
70%
80%
90%
Time
Ignorance
Ignorance
This is when we makecritical decisions

12. 100 1 2 3 4 5 6 7 8 9
100%
0
10%
20%
30%
40%
50%
60%
70%
80%
90%
Time
Ignorance
Ignorance
Breakthrough
Can we anticipatethis moment?

13. Is
there
any
impediments
to
breakthroughs
in
the
way
we
develop
soGware?

14. Hmm...
let
me
think

15. Learning
impediments
Time pressure --> estimations / expectations
Domain Experts availability / First Person experience
Learning Tools --> Discussion space, whiteboards, etc
Safety --> consequences of mistakes / Test env., etc.
Organization & Logistics --> noise, interruptions
Architecture
Food

16. 100 1 2 3 4 5 6 7 8 9
100%
0
10%
20%
30%
40%
50%
60%
70%
80%
90%
Time
Ignorance
Ignorance
Breakthrough
Ignorance

17. Some
things
work
pre=y
well
Focusing on Core Domain
Software Development as a Learning
Process
Explicit Bounded Context management

18. Establish
a
defensive
perimeter

19. ...and
a
fence

20. Know
your
borders
Our Bounded Context
Friendly BC
Pool
Promo
Campaign
...
ACL
ACL
External Service Provider
...
ACL
API
Data Exchange
Danger 1
Danger 2
obscure unnecessary
complicated concept
Promozione
FilterCondition
Reward
Legacy Mess

21. Some
things
work
pre=y
well
Focusing on Core Domain
Developing software as a learning process
Explicit bounded context management
Modeling the domain starting from Events

22. flow
Event
Event
Event
Event
Event
Domain
Experts
like
Events

23. flow
Event
Event
Event
Event
Event
Domain
Experts
like
Events
Command
Command

24. flow
Event
Event
Event
Event
Event
Domain
Experts
like
Events
Command
Command
Command Event

26. But...

29. Why?

30. 2
similar
problems

31. STOP
Validation

32. We
should
prevent
the
user
from
entering
incorrect
data.

33. The Notorious
Pub
hypothesis

35. Why
doesn’t
the
police
shut
down
this
place?
Mother:

36. ...

37. There’s
a
universe
out
there

38. Same
data
different
behaviour

39. Before AGer
missing
or
inconsistent
informaSon
ModificaSons
are
possible
DraG-­‐like
semanScs
all
mandatory
informaSon
present
No
changes
allowed
Printed
&
Signed
paper
semanScs

40. DraG Contract
Deal
Source Executable
negoSaSon
finalize
sign
off
compile
Cart
OrderPlan

41. CollaboraSve
ConstrucSon
MissingRoof
Warning
Comments
&
ConversaOon
Incomplete, growingartifact

42. ...just
like
building
soGware

43. The Deja-vu
hypothesis

45. ...not
always

46. What
if
the
domain
expert
is...
badly
wrong

47. Boss:
Users
must
follow
a
prescripSve,
mandatory
process

48. User:
The
process
as-­‐is
cannot
be
applied
in
pracSce

49. Boss:
Users
must
follow
a
prescripSve,
mandatory
process

51. Problem
is...

53. ©
Alberto
Brandolini
-­‐
2008-­‐2010
I’ve
tried
all
this
sh*t,
man...
...and
your
idea
doesn’t
work...

54. Some
problems
have
been
solved
well
in
soGware
development

55. ©
Alberto
Brandolini
-­‐
2008-­‐2010
Don’t
push
it
too
far...
but
we’ve
learnt
something

56. How we thought
we solved the
problem

58. R.I.P.

60. Maybe
a
be=er
example...
Why
don’t
we
just
teach
them
to
use
github?

61. Cognitive load

62. ©
Alberto
Brandolini
-­‐
2008-­‐2010
They’re
users,
not
hackers
too
much
cogniSve
load

63. Integration
strategies

64. Core
Domain
Strategy:
Simple enough to be
included (in the domain)
Good architectural
integration
UX Demanding (..?)
...increasing amount of
generic requirements
Collaboration

65. Where’s
the
instrucSon
manual?

66. UX
Demanding
...pervasive changes in presentation layer
user implicit expectations are high
if it’s not beautiful & simple it won’t work
...remember we’re changing people’s behaviour

67. Conformist
(hopefully) better
UI
Lock-in
(surrendering to
zombies)
Our
stuff
Big Collaboration
Software

68. Zombies
can
be
friendly
aGer
all...

69. Welcome

70. in

71. the

72. world

73. of

74.
plugin

76. customization

77. Separate
Ways
lightweight links
user cognitive
load increased
Collaboration
app
Our
B.C.

78. Shared
Kernel
Potentially reusable
possibly overkill for
generic subdomain
unpredictable social
consequences (the
wizard)
Core domain
Collaboration

79. Domain-­‐Specific
commands
Domain-­‐agnosSc
primiSves

80. ©
Alberto
Brandolini
-­‐
2008-­‐2010
Yeah
...the
problem’s
sSll
open
...what
about
a
White
Russian?

81. From
the
UX
expert
Need
Help

82. Results
-­‐
Confidence
-­‐
Safety
Build
Trust

83. (Having
ideas
!=
being
right)
Experiment

84. be
prepared
to
surprises
(we
are
changing
an
ecosystem)
Measure

85. We’re
both
learning
now...

86. Thank
you
alberto.brandolini@avanscoperta.it
hDp://ziobrando.blogspot.com
twiDer:
ziobrando