<s>
Object-oriented	B-Application
design	I-Application
(	O
OOD	O
)	O
is	O
the	O
process	O
of	O
planning	O
a	O
system	B-Language
of	I-Language
interacting	I-Language
objects	I-Language
for	O
the	O
purpose	O
of	O
solving	O
a	O
software	O
problem	O
.	O
</s>
<s>
An	O
object	O
contains	O
encapsulated	B-Application
data	O
and	O
procedures	O
grouped	O
together	O
to	O
represent	O
an	O
entity	O
.	O
</s>
<s>
An	O
object-oriented	B-Language
program	O
is	O
described	O
by	O
the	O
interaction	O
of	O
these	O
objects	O
.	O
</s>
<s>
Object-oriented	B-Application
design	I-Application
is	O
the	O
discipline	O
of	O
defining	O
the	O
objects	O
and	O
their	O
interactions	O
to	O
solve	O
a	O
problem	O
that	O
was	O
identified	O
and	O
documented	O
during	O
object-oriented	B-Application
analysis	I-Application
.	O
</s>
<s>
What	O
follows	O
is	O
a	O
description	O
of	O
the	O
class-based	B-Application
subset	O
of	O
object-oriented	B-Application
design	I-Application
,	O
which	O
does	O
not	O
include	O
object	B-Application
prototype-based	I-Application
approaches	O
where	O
objects	O
are	O
not	O
typically	O
obtained	O
by	O
instantiating	O
classes	O
but	O
by	O
cloning	O
other	O
(	O
prototype	O
)	O
objects	O
.	O
</s>
<s>
Object-oriented	B-Application
design	I-Application
is	O
a	O
method	O
of	O
design	O
encompassing	O
the	O
process	O
of	O
object-oriented	B-Language
decomposition	O
and	O
a	O
notation	O
for	O
depicting	O
both	O
logical	O
and	O
physical	O
as	O
well	O
as	O
state	O
and	O
dynamic	O
models	O
of	O
the	O
system	O
under	O
design	O
.	O
</s>
<s>
The	O
input	O
for	O
object-oriented	B-Application
design	I-Application
is	O
provided	O
by	O
the	O
output	O
of	O
object-oriented	B-Application
analysis	I-Application
.	O
</s>
<s>
Realize	O
that	O
an	O
output	O
artifact	O
does	O
not	O
need	O
to	O
be	O
completely	O
developed	O
to	O
serve	O
as	O
input	O
of	O
object-oriented	B-Application
design	I-Application
;	O
analysis	O
and	O
design	O
may	O
occur	O
in	O
parallel	O
,	O
and	O
in	O
practice	O
the	O
results	O
of	O
one	O
activity	O
can	O
feed	O
the	O
other	O
in	O
a	O
short	O
feedback	O
cycle	O
through	O
an	O
iterative	O
process	O
.	O
</s>
<s>
Some	O
typical	O
input	O
artifacts	O
for	O
object-oriented	B-Application
design	I-Application
are	O
:	O
</s>
<s>
Conceptual	B-Application
model	I-Application
:	O
The	O
result	O
of	O
object-oriented	B-Application
analysis	I-Application
,	O
it	O
captures	O
concepts	O
in	O
the	O
problem	B-General_Concept
domain	I-General_Concept
.	O
</s>
<s>
The	O
conceptual	B-Application
model	I-Application
is	O
explicitly	O
chosen	O
to	O
be	O
independent	O
of	O
implementation	O
details	O
,	O
such	O
as	O
concurrency	B-Operating_System
or	O
data	O
storage	O
.	O
</s>
<s>
Use	B-Architecture
case	I-Architecture
:	O
A	O
description	O
of	O
sequences	O
of	O
events	O
that	O
,	O
taken	O
together	O
,	O
lead	O
to	O
a	O
system	O
doing	O
something	O
useful	O
.	O
</s>
<s>
Each	O
use	B-Architecture
case	I-Architecture
provides	O
one	O
or	O
more	O
scenarios	O
that	O
convey	O
how	O
the	O
system	O
should	O
interact	O
with	O
the	O
users	O
called	O
actors	O
to	O
achieve	O
a	O
specific	O
business	O
goal	O
or	O
function	O
.	O
</s>
<s>
Use	B-Architecture
case	I-Architecture
actors	O
may	O
be	O
end	O
users	O
or	O
other	O
systems	O
.	O
</s>
<s>
In	O
many	O
circumstances	O
use	B-Architecture
cases	I-Architecture
are	O
further	O
elaborated	O
into	O
use	B-Language
case	I-Language
diagrams	I-Language
.	O
</s>
<s>
Use	B-Language
case	I-Language
diagrams	I-Language
are	O
used	O
to	O
identify	O
the	O
actor	O
(	O
users	O
or	O
other	O
systems	O
)	O
and	O
the	O
processes	O
they	O
perform	O
.	O
</s>
<s>
System	O
sequence	O
diagram	O
:	O
A	O
system	O
sequence	O
diagrams	O
(	O
SSD	O
)	O
is	O
a	O
picture	O
that	O
shows	O
,	O
for	O
a	O
particular	O
scenario	O
of	O
a	O
use	B-Architecture
case	I-Architecture
,	O
the	O
events	O
that	O
external	O
actors	O
generate	O
,	O
their	O
order	O
,	O
and	O
possible	O
inter-system	O
events	O
.	O
</s>
<s>
User	B-Application
interface	I-Application
documentations	O
(	O
if	O
applicable	O
)	O
:	O
Document	O
that	O
shows	O
and	O
describes	O
the	O
look	B-Application
and	I-Application
feel	I-Application
of	O
the	O
end	O
product	O
's	O
user	B-Application
interface	I-Application
.	O
</s>
<s>
Relational	B-Architecture
data	I-Architecture
model	I-Architecture
(	O
if	O
applicable	O
)	O
:	O
A	O
data	O
model	O
is	O
an	O
abstract	O
model	O
that	O
describes	O
how	O
data	O
is	O
represented	O
and	O
used	O
.	O
</s>
<s>
If	O
an	O
object	B-Application
database	I-Application
is	O
not	O
used	O
,	O
the	O
relational	B-Architecture
data	I-Architecture
model	I-Architecture
should	O
usually	O
be	O
created	O
before	O
the	O
design	O
,	O
since	O
the	O
strategy	O
chosen	O
for	O
object-relational	B-General_Concept
mapping	I-General_Concept
is	O
an	O
output	O
of	O
the	O
OO	O
design	O
process	O
.	O
</s>
<s>
However	O
,	O
it	O
is	O
possible	O
to	O
develop	O
the	O
relational	B-Architecture
data	I-Architecture
model	I-Architecture
and	O
the	O
object-oriented	B-Application
design	I-Application
artifacts	O
in	O
parallel	O
,	O
and	O
the	O
growth	O
of	O
an	O
artifact	O
can	O
stimulate	O
the	O
refinement	O
of	O
other	O
artifacts	O
.	O
</s>
<s>
The	O
five	O
basic	O
concepts	O
of	O
object-oriented	B-Application
design	I-Application
are	O
the	O
implementation	O
level	O
features	O
that	O
are	O
built	O
into	O
the	O
programming	O
language	O
.	O
</s>
<s>
Information	B-Application
hiding	I-Application
:	O
The	O
ability	O
to	O
protect	O
some	O
components	O
of	O
the	O
object	O
from	O
external	O
entities	O
.	O
</s>
<s>
Inheritance	B-Language
:	O
The	O
ability	O
for	O
a	O
class	O
to	O
extend	O
or	O
override	O
functionality	O
of	O
another	O
class	O
.	O
</s>
<s>
Interface	O
(	O
object-oriented	B-Language
programming	I-Language
)	O
:	O
The	O
ability	O
to	O
defer	O
the	O
implementation	O
of	O
a	O
method	O
.	O
</s>
<s>
Polymorphism	B-Application
(	O
specifically	O
,	O
Subtyping	O
)	O
:	O
The	O
ability	O
to	O
replace	O
an	O
object	O
with	O
its	O
subobjects	O
.	O
</s>
<s>
Defining	O
objects	O
mothers	O
,	O
creating	O
class	O
diagram	O
from	O
conceptual	B-Application
diagram	I-Application
:	O
Usually	O
map	O
entity	O
to	O
class	O
.	O
</s>
<s>
Identifying	O
attributes	B-General_Concept
.	O
</s>
<s>
Object-oriented	B-Application
design	I-Application
patterns	O
typically	O
show	O
relationships	O
and	O
interactions	O
between	O
classes	O
or	O
objects	O
,	O
without	O
specifying	O
the	O
final	O
application	O
classes	O
or	O
objects	O
that	O
are	O
involved	O
.	O
</s>
<s>
Define	O
application	B-Application
framework	I-Application
(	O
if	O
applicable	O
)	O
:	O
Application	B-Application
framework	I-Application
is	O
usually	O
a	O
set	O
of	O
libraries	O
or	O
classes	O
that	O
are	O
used	O
to	O
implement	O
the	O
standard	O
structure	O
of	O
an	O
application	O
for	O
a	O
specific	O
operating	O
system	O
.	O
</s>
<s>
If	O
a	O
relational	B-Application
database	I-Application
is	O
used	O
,	O
design	O
the	O
object	O
relation	O
mapping	O
.	O
</s>
<s>
Class	O
diagram	O
-	O
A	O
class	O
diagram	O
is	O
a	O
type	O
of	O
static	O
structure	O
UML	B-Language
diagram	I-Language
that	O
describes	O
the	O
structure	O
of	O
a	O
system	O
by	O
showing	O
the	O
system	O
's	O
classes	O
,	O
its	O
attributes	B-General_Concept
,	O
and	O
the	O
relationships	O
between	O
the	O
classes	O
.	O
</s>
<s>
Dependency	B-Library
injection	I-Library
:	O
The	O
basic	O
idea	O
is	O
that	O
if	O
an	O
object	O
depends	O
upon	O
having	O
an	O
instance	O
of	O
some	O
other	O
object	O
then	O
the	O
needed	O
object	O
is	O
"	O
injected	O
"	O
into	O
the	O
dependent	O
object	O
;	O
for	O
example	O
,	O
being	O
passed	O
a	O
database	O
connection	O
as	O
an	O
argument	O
to	O
the	O
constructor	O
instead	O
of	O
creating	O
one	O
internally	O
.	O
</s>
<s>
Composite	B-Library
reuse	I-Library
principle	I-Library
:	O
Favor	O
polymorphic	B-Application
composition	B-Language
of	O
objects	O
over	O
inheritance	B-Language
.	O
</s>
