This document defines key concepts related to aspect-oriented programming (AOP) such as concerns, core concerns, cross-cutting concerns, aspects, and separation of concerns. It explains that AOP is a technique that supports cleanly separating concerns through modularization and loosely coupling components. It also discusses that aspect-oriented software development is a combination of mechanisms and methodologies to separate concerns at different abstraction levels using a combination of language, environment, and methods.

1. Otavio
Ferreira
(@otaviofff)
Technical
Architect,
Scrum
Master
Oct
2007

2. • AOSD
tag
cloud
modularity
aspect
dominant
decomposi@on
AOSD
concern
core
concern
October
2007
AOP
separa@on
of
concerns
advice
join
point
cross-­‐cuCng
concerns
MIH
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point
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3. • Concern
– An
area
of
interest
or
focus
in
a
system.
– The
primary
criteria
for
decomposing
SW
into
smaller,
more
manageable
and
comprehensible
parts.
Text
Picture
Video
Quote
Link
Chat
Tumblelog
October
2007
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Excep@on
Handling
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4. • Separa@on
of
concerns
– Based
on
the
Divide-­‐and-­‐Conquer
strategy.
– Focused
on
breaking
down
the
SW
into
dis@nct
parts
that
overlap
in
func@onality
as
liUle
as
possible.
October
2007
MIH
SWAT
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5. • Core
concern
– Core
business
related
concern.
– Domain
specific
concern.
– Func@onal
requirement.
– Can
be
cleanly
encapsulated
in
a
generalized
procedure
(i.e.
object,
method,
procedure,
API).
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2007
MIH
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6. • Cross-­‐cuCng
concern
– Common
func@onality
orthogonal
to
core
concern.
– Non-­‐func@onal
requirement.
– Can
NOT
be
cleanly
encapsulated
in
a
generalized
procedure
(i.e.
object,
method,
procedure,
API).
October
2007
MIH
SWAT
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7. • Dominant
decomposi@on
– The
SW
can
be
modularized
in
only
one
way
at
a
@me.
– Concerns
that
do
not
align
with
that
modulariza@on
end
up
scaUered
across
many
modules
and
tangled
with
one
another.
October
2007
MIH
SWAT
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8. • ScaUering
and
tangling
– Cross-­‐cuCng
concerns
o^en
cannot
be
cleanly
decomposed
from
the
rest
of
the
system
in
both
the
design
and
implementa@on.
Excep@on
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2007
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9. • Aspect
(Finally!)
– A
part
of
a
program
that
cross-­‐cuts
its
core
concerns,
therefore
“viola@ng”
its
separa@on
of
concerns.
Logging
Excep@on
Handling
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2007
MIH
SWAT
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10. • Modularity
– AOP
is
an
advance
in
modulariza@on.
– Loosely
coupled
concerns
/
components.
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2007
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11. • Aspect-­‐oriented
programming
– A
technique
used
to
support
the
programmer
in
cleanly
separa@ng
components
and
aspects
from
each
other.
– Centers
its
aUen@on
on
the
code
modulariza@on,
providing
mechanisms
to
separate
cross-­‐cuCng
concerns
at
code
level.
– Related
to
the
language.
October
2007
MIH
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12. • Aspect-­‐oriented
so^ware
development
–
A
combina@on
of
mechanisms
and
methodologies
that
facilitate
in
separa@ng
concerns
at
different
abstrac@on
levels.
– Uses
a
combina@on
of
language,
environment,
and
method.
October
2007
MIH
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13. • Aspect-­‐oriented
applica@on
– Consists
of:
• Component
language
(C#,
Java,
etc.)
• Aspect-­‐oriented
language
/
framework
• Aspect
weaver
October
2007
MIH
SWAT
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