<s>
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
(	O
MDA	O
)	O
is	O
a	O
software	O
design	O
approach	O
for	O
the	O
development	O
of	O
software	O
systems	O
.	O
</s>
<s>
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
is	O
a	O
kind	O
of	O
domain	O
engineering	O
,	O
and	O
supports	O
model-driven	B-Language
engineering	I-Language
of	O
software	O
systems	O
.	O
</s>
<s>
It	O
was	O
launched	O
by	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	B-Architecture
)	O
in	O
2001	O
.	O
</s>
<s>
OMG	B-Architecture
literature	O
speaks	O
of	O
three	O
such	O
levels	O
of	O
abstraction	O
,	O
or	O
architectural	O
viewpoints	O
:	O
the	O
Computation-independent	O
Model	O
(	O
CIM	O
)	O
,	O
the	O
Platform-independent	B-Architecture
model	I-Architecture
(	O
PIM	B-Architecture
)	O
,	O
and	O
the	O
Platform-specific	B-Architecture
model	I-Architecture
(	O
PSM	O
)	O
.	O
</s>
<s>
The	O
CIM	O
describes	O
a	O
system	O
conceptually	O
,	O
the	O
PIM	B-Architecture
describes	O
the	O
computational	O
aspects	O
of	O
a	O
system	O
without	O
reference	O
to	O
the	O
technologies	O
that	O
may	O
be	O
used	O
to	O
implement	O
it	O
,	O
and	O
the	O
PSM	O
provides	O
the	O
technical	O
details	O
necessary	O
to	O
implement	O
the	O
system	O
.	O
</s>
<s>
The	O
OMG	B-Architecture
Guide	O
notes	O
,	O
though	O
,	O
that	O
these	O
three	O
architectural	O
viewpoints	O
are	O
useful	O
,	O
but	O
are	O
just	O
three	O
of	O
many	O
possible	O
viewpoints	O
.	O
</s>
<s>
The	O
OMG	B-Architecture
organization	O
provides	O
specifications	O
rather	O
than	O
implementations	O
,	O
often	O
as	O
answers	O
to	O
Requests	O
for	O
Proposals	O
(	O
RFPs	O
)	O
.	O
</s>
<s>
Implementations	O
come	O
from	O
private	O
companies	O
or	O
open	B-License
source	I-License
groups	O
.	O
</s>
<s>
The	O
MDA	O
model	O
is	O
related	O
to	O
multiple	O
standards	O
,	O
including	O
the	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
,	O
the	O
Meta-Object	B-Application
Facility	I-Application
(	O
MOF	O
)	O
,	O
XML	B-Language
Metadata	I-Language
Interchange	I-Language
(	O
XMI	O
)	O
,	O
Enterprise	B-Language
Distributed	I-Language
Object	I-Language
Computing	I-Language
(	O
EDOC	O
)	O
,	O
the	O
Software	O
Process	O
Engineering	O
Metamodel	O
(	O
SPEM	O
)	O
,	O
and	O
the	O
Common	O
Warehouse	O
Metamodel	O
(	O
CWM	O
)	O
.	O
</s>
<s>
Note	O
that	O
the	O
term	O
“	O
architecture	O
”	O
in	O
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
does	O
not	O
refer	O
to	O
the	O
architecture	O
of	O
the	O
system	O
being	O
modeled	O
,	O
but	O
rather	O
to	O
the	O
architecture	O
of	O
the	O
various	O
standards	O
and	O
model	O
forms	O
that	O
serve	O
as	O
the	O
technology	O
basis	O
for	O
MDA	O
.	O
</s>
<s>
Executable	B-Language
UML	I-Language
was	O
the	O
UML	B-Language
profile	O
used	O
when	O
MDA	O
was	O
born	O
.	O
</s>
<s>
Now	O
,	O
the	O
OMG	B-Architecture
is	O
promoting	O
fUML	O
,	O
instead	O
.	O
</s>
<s>
The	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
holds	O
registered	O
trademarks	O
on	O
the	O
term	O
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
and	O
its	O
acronym	O
MDA	O
,	O
as	O
well	O
as	O
trademarks	O
for	O
terms	O
such	O
as	O
:	O
Model	O
Based	O
Application	O
Development	O
,	O
Model	B-Architecture
Driven	I-Architecture
Application	I-Architecture
Development	O
,	O
Model	O
Based	O
Application	O
Development	O
,	O
Model	O
Based	O
Programming	O
,	O
Model	O
Driven	O
Systems	O
,	O
and	O
others	O
.	O
</s>
<s>
OMG	B-Architecture
focuses	O
Model	O
Driven	O
Architecture®	O
on	O
forward	O
engineering	O
,	O
i.e.	O
</s>
<s>
OMG	B-Architecture
's	O
ADTF	O
(	O
Analysis	O
and	O
Design	O
Task	O
Force	O
)	O
group	O
leads	O
this	O
effort	O
.	O
</s>
<s>
Knowledge	B-Language
Discovery	I-Language
Metamodel	I-Language
(	O
KDM	O
)	O
is	O
the	O
furthest	O
along	O
of	O
these	O
efforts	O
,	O
and	O
describes	O
information	O
systems	O
in	O
terms	O
of	O
various	O
assets	O
(	O
programs	O
,	O
specifications	O
,	O
data	O
,	O
test	O
files	O
,	O
database	O
schemas	O
,	O
etc	O
.	O
</s>
<s>
The	O
design	O
addresses	O
the	O
functional	O
(	O
use	B-Architecture
case	I-Architecture
)	O
requirements	O
while	O
architecture	O
provides	O
the	O
infrastructure	O
through	O
which	O
non-functional	O
requirements	O
like	O
scalability	O
,	O
reliability	O
and	O
performance	O
are	O
realized	O
.	O
</s>
<s>
MDA	O
envisages	O
that	O
the	O
platform	B-Architecture
independent	I-Architecture
model	I-Architecture
(	O
PIM	B-Architecture
)	O
,	O
which	O
represents	O
a	O
conceptual	O
design	O
realizing	O
the	O
functional	O
requirements	O
,	O
will	O
survive	O
changes	O
in	O
realization	O
technologies	O
and	O
software	B-Architecture
architectures	I-Architecture
.	O
</s>
<s>
Of	O
particular	O
importance	O
to	O
Model	B-Architecture
Driven	I-Architecture
Architecture	I-Architecture
is	O
the	O
notion	O
of	O
model	B-Language
transformation	I-Language
.	O
</s>
<s>
A	O
specific	O
standard	O
language	O
for	O
model	B-Language
transformation	I-Language
has	O
been	O
defined	O
by	O
OMG	B-Architecture
called	O
QVT	B-Language
.	O
</s>
<s>
The	O
OMG	B-Architecture
organization	O
provides	O
rough	O
specifications	O
rather	O
than	O
implementations	O
,	O
often	O
as	O
answers	O
to	O
Requests	O
for	O
Proposals	O
(	O
RFPs	O
)	O
.	O
</s>
<s>
The	O
OMG	B-Architecture
documents	O
the	O
overall	O
process	O
in	O
a	O
document	O
called	O
the	O
MDA	O
Guide	O
.	O
</s>
<s>
a	O
UML	B-Language
model	O
)	O
or	O
metamodel	O
(	O
e.g.	O
</s>
<s>
For	O
example	O
,	O
an	O
analyst	O
may	O
create	O
a	O
UML	B-Language
initial	O
model	O
from	O
its	O
observation	O
of	O
some	O
loose	O
business	O
situation	O
while	O
a	O
Java	O
model	O
may	O
be	O
automatically	O
derived	O
from	O
this	O
UML	B-Language
model	O
by	O
a	O
Model	B-Language
transformation	I-Language
operation	O
.	O
</s>
<s>
Implementations	O
of	O
the	O
OMG	B-Architecture
specifications	O
come	O
from	O
private	O
companies	O
or	O
open	B-License
source	I-License
groups	O
.	O
</s>
<s>
One	O
important	O
source	O
of	O
implementations	O
for	O
OMG	B-Architecture
specifications	O
is	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
(	O
EF	O
)	O
.	O
</s>
<s>
Many	O
implementations	O
of	O
OMG	B-Architecture
modeling	O
standards	O
may	O
be	O
found	O
in	O
the	O
Eclipse	B-Language
Modeling	I-Language
Framework	I-Language
(	O
EMF	O
)	O
or	O
Graphical	B-Language
Modeling	I-Language
Framework	I-Language
(	O
GMF	O
)	O
,	O
the	B-Application
Eclipse	I-Application
foundation	I-Application
is	O
also	O
developing	O
other	O
tools	O
of	O
various	O
profiles	O
as	O
GMT	O
.	O
</s>
<s>
Eclipse	O
's	O
compliance	O
to	O
OMG	B-Architecture
specifications	O
is	O
often	O
not	O
strict	O
.	O
</s>
<s>
This	O
is	O
true	O
for	O
example	O
for	O
OMG	B-Architecture
's	O
EMOF	B-Application
standard	O
,	O
which	O
EMF	O
approximates	O
with	O
its	O
Ecore	O
implementation	O
.	O
</s>
<s>
More	O
examples	O
may	O
be	O
found	O
in	O
the	O
M2M	O
project	O
implementing	O
the	O
QVT	B-Language
standard	O
or	O
in	O
the	O
M2T	O
project	O
implementing	O
the	O
MOF2Text	O
standard	O
.	O
</s>
<s>
One	O
should	O
be	O
careful	O
not	O
to	O
confuse	O
the	O
List	O
of	O
MDA	O
Tools	O
and	O
the	O
List	B-Protocol
of	I-Protocol
UML	I-Protocol
tools	I-Protocol
,	O
the	O
former	O
being	O
much	O
broader	O
.	O
</s>
<s>
A	O
UML	B-Language
CASE	O
tool	O
is	O
typically	O
a	O
'	O
fixed	O
metamodel	O
tool	O
 '	O
since	O
it	O
has	O
been	O
hard-wired	O
to	O
work	O
only	O
with	O
a	O
given	O
version	O
of	O
the	O
UML	B-Language
metamodel	O
(	O
e.g.	O
</s>
<s>
Selecting	O
one	O
of	O
a	O
number	O
of	O
supported	O
reference	B-Architecture
architectures	I-Architecture
like	O
Java	B-Language
EE	I-Language
or	O
Microsoft	O
.NET	O
,	O
</s>
<s>
Indeed	O
,	O
a	O
key	O
absent	O
technical	O
standard	O
of	O
the	O
MDA	O
approach	O
(	O
that	O
of	O
an	O
action	O
language	O
syntax	O
for	O
Executable	B-Language
UML	I-Language
)	O
has	O
been	O
bridged	O
by	O
some	O
vendors	O
by	O
adapting	O
the	O
original	O
Shlaer-Mellor	O
Action	O
Language	O
(	O
modified	O
for	O
UML	B-Language
)	O
.	O
</s>
<s>
Potential	O
concerns	O
that	O
have	O
been	O
raised	O
with	O
the	O
OMG	B-Architecture
MDA	O
approach	O
include	O
:	O
</s>
<s>
an	O
action	O
semantic	O
language	O
for	O
xtUML	B-Language
)	O
,	O
or	O
are	O
yet	O
to	O
be	O
implemented	O
in	O
a	O
standard	O
manner	O
(	O
e.g.	O
</s>
<s>
a	O
QVT	B-Language
transformation	O
engine	O
or	O
a	O
PIM	B-Architecture
with	O
a	O
virtual	O
execution	O
environment	O
)	O
.	O
</s>
<s>
This	O
aligns	O
with	O
OMG	B-Architecture
's	O
vision	O
that	O
MDA	O
should	O
allow	O
modelling	O
of	O
a	O
problem	O
domain	O
's	O
full	O
complexity	O
in	O
UML	B-Language
(	O
and	O
related	O
standards	O
)	O
with	O
subsequent	O
transformation	O
to	O
a	O
complete	O
(	O
executable	O
)	O
application	O
.	O
</s>
<s>
Pragmatic	O
MDA	O
blends	O
the	O
literal	O
standards	O
from	O
OMG	B-Architecture
's	O
MDA	O
with	O
more	O
traditional	O
model	O
driven	O
mechanisms	O
such	O
as	O
round-trip	B-Application
engineering	I-Application
that	O
provides	O
support	O
for	O
adapting	O
implementation	O
artifacts	O
.	O
</s>
<s>
OMG	B-Architecture
Track	O
Record	O
:	O
The	O
OMG	B-Architecture
consortium	O
who	O
sponsor	O
the	O
MDA	O
approach	O
(	O
and	O
own	O
the	O
MDA	O
trademark	O
)	O
also	O
introduced	O
and	O
sponsored	O
the	O
CORBA	O
standard	O
which	O
itself	O
failed	O
to	O
materialise	O
as	O
a	O
widely	O
utilised	O
standard	O
.	O
</s>
<s>
xtUML	B-Language
)	O
is	O
more	O
abstract	O
(	O
than	O
,	O
say	O
,	O
Java	O
or	O
C#	O
)	O
and	O
exists	O
interwoven	O
with	O
traditional	O
UML	B-Language
artifacts	O
(	O
e.g.	O
</s>
<s>
Code	B-Application
generation	I-Application
means	O
that	O
the	O
user	O
abstractly	O
models	O
solutions	O
,	O
which	O
are	O
connoted	O
by	O
some	O
model	O
data	O
,	O
and	O
then	O
an	O
automated	O
tool	O
derives	O
from	O
the	O
models	O
parts	O
or	O
all	O
of	O
the	O
source	O
code	O
for	O
the	O
software	O
system	O
.	O
</s>
<s>
In	O
some	O
tools	O
,	O
the	O
user	O
can	O
provide	O
a	O
skeleton	O
of	O
the	O
program	O
source	O
code	O
,	O
in	O
the	O
form	O
of	O
a	O
source	O
code	O
template	B-Application
where	O
predefined	O
tokens	O
are	O
then	O
replaced	O
with	O
program	O
source	O
code	O
parts	O
during	O
the	O
code	B-Application
generation	I-Application
process	O
.	O
</s>
<s>
An	O
often	O
cited	O
criticism	O
is	O
that	O
the	O
UML	B-Language
diagrams	I-Language
just	O
lack	O
the	O
detail	O
which	O
is	O
needed	O
to	O
contain	O
the	O
same	O
information	O
as	O
is	O
covered	O
with	O
the	O
program	O
source	O
.	O
</s>
