<s>
Object-oriented	B-Application
analysis	I-Application
and	I-Application
design	I-Application
(	O
OOAD	B-Application
)	O
is	O
a	O
technical	O
approach	O
for	O
analyzing	O
and	O
designing	O
an	O
application	O
,	O
system	O
,	O
or	O
business	O
by	O
applying	O
object-oriented	B-Language
programming	I-Language
,	O
as	O
well	O
as	O
using	O
visual	O
modeling	O
throughout	O
the	O
software	O
development	O
process	O
to	O
guide	O
stakeholder	O
communication	O
and	O
product	O
quality	O
.	O
</s>
<s>
OOAD	B-Application
in	O
modern	O
software	O
engineering	O
is	O
typically	O
conducted	O
in	O
an	O
iterative	O
and	O
incremental	O
way	O
.	O
</s>
<s>
The	O
outputs	O
of	O
OOAD	B-Application
activities	O
are	O
analysis	O
models	O
(	O
for	O
OOA	O
)	O
and	O
design	O
models	O
(	O
for	O
OOD	O
)	O
respectively	O
.	O
</s>
<s>
In	O
the	O
early	O
days	O
of	O
object-oriented	B-Language
technology	I-Language
before	O
the	O
mid-1990s	O
,	O
there	O
were	O
many	O
different	O
competing	O
methodologies	O
for	O
software	O
development	O
and	O
object-oriented	B-Application
modeling	I-Application
,	O
often	O
tied	O
to	O
specific	O
Computer	B-Application
Aided	I-Application
Software	I-Application
Engineering	I-Application
(	O
CASE	O
)	O
tool	O
vendors	O
.	O
</s>
<s>
Some	O
of	O
the	O
well-known	O
early	O
object-oriented	B-Language
methodologies	O
were	O
from	O
and	O
inspired	O
by	O
gurus	O
such	O
as	O
Grady	O
Booch	O
,	O
James	O
Rumbaugh	O
,	O
Ivar	O
Jacobson	O
(	O
the	O
Three	O
Amigos	O
)	O
,	O
Robert	O
Martin	O
,	O
Peter	O
Coad	O
,	O
Sally	O
Shlaer	O
,	O
Stephen	O
Mellor	O
,	O
and	O
Rebecca	O
Wirfs-Brock	O
.	O
</s>
<s>
In	O
1994	O
,	O
the	O
Three	O
Amigos	O
of	O
Rational	O
Software	O
started	O
working	O
together	O
to	O
develop	O
the	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
.	O
</s>
<s>
Later	O
,	O
together	O
with	O
Philippe	O
Kruchten	O
and	O
Walker	O
Royce	O
(	O
eldest	O
son	O
of	O
Winston	O
Royce	O
)	O
,	O
they	O
have	O
led	O
a	O
successful	O
mission	O
to	O
merge	O
their	O
own	O
methodologies	O
,	O
OMT	B-Application
,	O
OOSE	B-Language
and	O
Booch	O
method	O
,	O
with	O
various	O
insights	O
and	O
experiences	O
from	O
other	O
industry	O
leaders	O
into	O
the	O
Rational	B-Application
Unified	I-Application
Process	I-Application
(	O
RUP	O
)	O
,	O
a	O
comprehensive	O
iterative	O
and	O
incremental	O
process	O
guide	O
and	O
framework	O
for	O
learning	O
industry	O
best	O
practices	O
of	O
software	O
development	O
and	O
project	O
management	O
.	O
</s>
<s>
Since	O
then	O
,	O
the	O
Unified	O
Process	O
family	O
has	O
become	O
probably	O
the	O
most	O
popular	O
methodology	O
and	O
reference	O
model	O
for	O
object-oriented	B-Application
analysis	I-Application
and	I-Application
design	I-Application
.	O
</s>
<s>
Although	O
it	O
is	O
possible	O
to	O
do	O
object-oriented	B-Language
development	O
using	O
a	O
waterfall	O
model	O
,	O
in	O
practice	O
most	O
object-oriented	B-Language
systems	O
are	O
developed	O
with	O
an	O
iterative	O
approach	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
in	O
object-oriented	B-Language
processes	O
"	O
analysis	O
and	O
design	O
"	O
are	O
often	O
considered	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
The	O
object-oriented	B-Language
paradigm	O
emphasizes	O
modularity	O
and	O
re-usability	O
.	O
</s>
<s>
The	O
goal	O
of	O
an	O
object-oriented	B-Language
approach	O
is	O
to	O
satisfy	O
the	O
"	O
openclosed	O
principle	O
"	O
.	O
</s>
<s>
In	O
the	O
object-oriented	B-Language
paradigm	O
this	O
is	O
often	O
accomplished	O
by	O
creating	O
a	O
new	O
subclass	O
of	O
an	O
existing	O
class	O
.	O
</s>
<s>
In	O
the	O
object-oriented	B-Language
paradigm	O
this	O
is	O
accomplished	O
by	O
defining	O
methods	O
that	O
invoke	O
services	O
on	O
objects	O
.	O
</s>
<s>
In	O
object-oriented	B-Language
analysis	O
this	O
is	O
typically	O
done	O
via	O
use	B-Architecture
cases	I-Architecture
and	O
abstract	O
definitions	O
of	O
the	O
most	O
important	O
objects	O
.	O
</s>
<s>
In	O
object-oriented	B-Language
design	O
the	O
emphasis	O
is	O
on	O
describing	O
the	O
various	O
objects	O
,	O
their	O
data	O
,	O
behavior	O
,	O
and	O
interactions	O
.	O
</s>
<s>
The	O
main	O
difference	O
between	O
object-oriented	B-Language
analysis	O
and	O
other	O
forms	O
of	O
analysis	O
is	O
that	O
by	O
the	O
object-oriented	B-Language
approach	O
we	O
organize	O
requirements	O
around	O
objects	O
,	O
which	O
integrate	O
both	O
behaviors	O
(	O
processes	O
)	O
and	O
states	O
(	O
data	O
)	O
modeled	O
after	O
real	O
world	O
objects	O
that	O
the	O
system	O
interacts	O
with	O
.	O
</s>
<s>
For	O
example	O
,	O
data	O
may	O
be	O
modeled	O
by	O
ER	B-Architecture
diagrams	I-Architecture
,	O
and	O
behaviors	O
by	O
flow	B-Language
charts	I-Language
or	O
structure	B-Application
charts	I-Application
.	O
</s>
<s>
Common	O
models	O
used	O
in	O
OOA	O
are	O
use	B-Architecture
cases	I-Architecture
and	O
object	B-Application
models	I-Application
.	O
</s>
<s>
Use	B-Architecture
cases	I-Architecture
describe	O
scenarios	O
for	O
standard	O
domain	O
functions	O
that	O
the	O
system	O
must	O
accomplish	O
.	O
</s>
<s>
Object	B-Application
models	I-Application
describe	O
the	O
names	O
,	O
class	O
relations	O
(	O
e.g.	O
</s>
<s>
During	O
object-oriented	B-Language
design	O
(	O
OOD	O
)	O
,	O
a	O
developer	O
applies	O
implementation	O
constraints	O
to	O
the	O
conceptual	O
model	O
produced	O
in	O
object-oriented	B-Language
analysis	O
.	O
</s>
<s>
Important	O
topics	O
during	O
OOD	O
also	O
include	O
the	O
design	O
of	O
software	B-Architecture
architectures	I-Architecture
by	O
applying	O
architectural	O
patterns	O
and	O
design	O
patterns	O
with	O
the	O
object-oriented	B-Language
design	O
principles	O
.	O
</s>
<s>
Object-oriented	B-Application
modeling	I-Application
(	O
OOM	O
)	O
is	O
a	O
common	O
approach	O
to	O
modeling	O
applications	O
,	O
systems	O
,	O
and	O
business	O
domains	O
by	O
using	O
the	O
object-oriented	B-Language
paradigm	O
throughout	O
the	O
entire	O
development	O
life	O
cycles	O
.	O
</s>
<s>
Object-oriented	B-Application
modeling	I-Application
typically	O
divides	O
into	O
two	O
aspects	O
of	O
work	O
:	O
the	O
modeling	O
of	O
dynamic	O
behaviors	O
like	O
business	O
processes	O
and	O
use	B-Architecture
cases	I-Architecture
,	O
and	O
the	O
modeling	O
of	O
static	O
structures	O
like	O
classes	O
and	O
components	O
.	O
</s>
<s>
The	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
and	O
SysML	B-Language
are	O
the	O
two	O
popular	O
international	O
standard	O
languages	O
used	O
for	O
object-oriented	B-Application
modeling	I-Application
.	O
</s>
<s>
A	O
key	O
goal	O
of	O
the	O
object-oriented	B-Language
approach	O
is	O
to	O
decrease	O
the	O
"	O
semantic	O
gap	O
"	O
between	O
the	O
system	O
and	O
the	O
real	O
world	O
,	O
and	O
to	O
have	O
the	O
system	O
be	O
constructed	O
using	O
terminology	O
that	O
is	O
almost	O
the	O
same	O
as	O
the	O
stakeholders	O
use	O
in	O
everyday	O
business	O
.	O
</s>
<s>
Object-oriented	B-Application
modeling	I-Application
is	O
an	O
essential	O
tool	O
to	O
facilitate	O
this	O
.	O
</s>
<s>
Object-oriented	B-Application
modeling	I-Application
enables	O
this	O
by	O
producing	O
abstract	O
and	O
accessible	O
descriptions	O
of	O
both	O
system	O
requirements	O
and	O
designs	O
,	O
i.e.	O
</s>
