<s>
Round-trip	B-Application
engineering	I-Application
(	O
RTE	O
)	O
is	O
a	O
functionality	O
of	O
software	B-Application
development	I-Application
tools	I-Application
that	O
synchronizes	O
two	O
or	O
more	O
related	O
software	O
artifacts	O
,	O
such	O
as	O
,	O
source	O
code	O
,	O
models	O
,	O
configuration	O
files	O
,	O
and	O
even	O
documentation	O
.	O
</s>
<s>
The	O
need	O
for	O
round-trip	B-Application
engineering	I-Application
arises	O
when	O
the	O
same	O
information	O
is	O
present	O
in	O
multiple	O
artifacts	O
and	O
therefore	O
an	O
inconsistency	O
may	O
occur	O
if	O
not	O
all	O
artifacts	O
are	O
consistently	O
updated	O
to	O
reflect	O
a	O
given	O
change	O
.	O
</s>
<s>
Round-trip	B-Application
engineering	I-Application
is	O
closely	O
related	O
to	O
traditional	O
software	B-General_Concept
engineering	I-General_Concept
disciplines	O
:	O
forward	O
engineering	O
(	O
creating	O
software	O
from	O
specifications	O
)	O
,	O
reverse	O
engineering	O
(	O
creating	O
specifications	O
from	O
existing	O
software	O
)	O
,	O
and	O
reengineering	O
(	O
understanding	O
existing	O
software	O
and	O
modifying	O
it	O
)	O
.	O
</s>
<s>
Round-trip	B-Application
engineering	I-Application
is	O
often	O
wrongly	O
defined	O
as	O
simply	O
supporting	O
both	O
forward	O
and	O
reverse	O
engineering	O
.	O
</s>
<s>
In	O
fact	O
,	O
the	O
key	O
characteristic	O
of	O
round-trip	B-Application
engineering	I-Application
that	O
distinguishes	O
it	O
from	O
forward	O
and	O
reverse	O
engineering	O
is	O
the	O
ability	O
to	O
synchronize	O
existing	O
artifacts	O
that	O
evolved	O
concurrently	O
by	O
incrementally	O
updating	O
each	O
artifact	O
to	O
reflect	O
changes	O
made	O
to	O
the	O
other	O
artifacts	O
.	O
</s>
<s>
Another	O
characteristic	O
of	O
round-trip	B-Application
engineering	I-Application
is	O
automatic	O
update	O
of	O
the	O
artifacts	O
in	O
response	O
to	O
automatically	O
detected	O
inconsistencies	O
.	O
</s>
<s>
Perhaps	O
the	O
most	O
common	O
form	O
of	O
round-trip	B-Application
engineering	I-Application
is	O
synchronization	O
between	O
UML	B-Language
(	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
)	O
models	O
and	O
the	O
corresponding	O
source	O
code	O
.	O
</s>
<s>
Many	O
commercial	O
tools	O
and	O
research	O
prototypes	O
support	O
this	O
form	O
of	O
RTE	O
;	O
a	O
2007	O
book	O
lists	O
Rational	B-Application
Rose	I-Application
,	O
Micro	B-Application
Focus	I-Application
Together	I-Application
,	O
ESS-Model	O
,	O
BlueJ	B-Language
,	O
and	O
Fujaba	O
among	O
those	O
capable	O
,	O
with	O
Fujaba	O
said	O
to	O
be	O
capable	O
to	O
also	O
identify	O
design	O
patterns	O
.	O
</s>
<s>
Usually	O
,	O
UML	B-Language
class	O
diagrams	O
are	O
supported	O
to	O
some	O
degree	O
;	O
however	O
,	O
certain	O
UML	B-Language
concepts	O
,	O
such	O
as	O
associations	O
and	O
containment	O
do	O
not	O
have	O
straightforward	O
representations	O
in	O
many	O
programming	O
languages	O
which	O
limits	O
the	O
usability	O
of	O
the	O
created	O
code	O
and	O
accuracy	O
of	O
code	O
analysis	O
(	O
e.g.	O
,	O
containment	O
is	O
hard	O
to	O
recognize	O
in	O
the	O
code	O
)	O
.	O
</s>
<s>
A	O
2005	O
book	O
on	O
Visual	B-Application
Studio	I-Application
notes	O
for	O
instance	O
that	O
a	O
common	O
problem	O
in	O
RTE	O
tools	O
is	O
that	O
the	O
model	O
reversed	O
is	O
not	O
the	O
same	O
as	O
the	O
original	O
one	O
,	O
unless	O
the	O
tools	O
are	O
helped	O
by	O
laborious	O
annotations	O
.	O
</s>
<s>
The	O
behavioral	O
parts	O
of	O
UML	B-Language
impose	O
even	O
more	O
challenges	O
for	O
RTE	O
.	O
</s>
<s>
A	O
more	O
tractable	O
form	O
of	O
round-trip	B-Application
engineering	I-Application
is	O
implemented	O
in	O
the	O
context	O
of	O
framework	O
application	B-Application
programming	I-Application
interfaces	I-Application
(	O
APIs	B-Application
)	O
,	O
whereby	O
a	O
model	O
describing	O
the	O
usage	O
of	O
a	O
framework	O
API	B-Application
by	O
an	O
application	O
is	O
synchronized	O
with	O
that	O
application	O
's	O
code	O
.	O
</s>
<s>
In	O
this	O
setting	O
,	O
the	O
API	B-Application
prescribes	O
all	O
correct	O
ways	O
the	O
framework	O
can	O
be	O
used	O
in	O
applications	O
,	O
which	O
allows	O
precise	O
and	O
complete	O
detection	O
of	O
API	B-Application
usages	O
in	O
the	O
code	O
as	O
well	O
as	O
creation	O
of	O
useful	O
code	O
implementing	O
correct	O
API	B-Application
usages	O
.	O
</s>
<s>
Two	O
prominent	O
RTE	O
implementations	O
in	O
this	O
category	O
are	O
framework-specific	B-Language
modeling	I-Language
languages	I-Language
and	O
Spring	B-Language
Roo	I-Language
.	O
</s>
<s>
Round-trip	B-Application
engineering	I-Application
is	O
critical	O
for	O
maintaining	O
consistency	O
among	O
multiple	O
models	O
and	O
between	O
the	O
models	O
and	O
the	O
code	O
in	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
's	O
(	O
OMG	O
)	O
Model-driven	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
OMG	O
proposed	O
the	O
QVT	B-Language
(	O
query/view/transformation	O
)	O
standard	O
to	O
handle	O
model	O
transformations	O
required	O
for	O
MDA	O
.	O
</s>
<s>
Round-trip	B-Application
engineering	I-Application
based	O
on	O
Unified	B-Language
Modeling	I-Language
Language	I-Language
(	O
UML	B-Language
)	O
needs	O
three	O
basic	O
components	O
for	O
software	O
development	O
:	O
</s>
<s>
UML	B-Language
Editor	O
for	O
the	O
Attributes	O
and	O
Methods	O
;	O
</s>
<s>
Visualisation	O
of	O
UML	B-Language
structure	O
.	O
</s>
<s>
An	O
example	O
of	O
basic	O
round-trip	B-Application
engineering	I-Application
is	O
accessible	O
as	O
a	O
web-based	O
Open	O
Source	O
tool	O
is	O
:	O
</s>
<s>
JavaScript	O
Class	O
Creator	O
allows	O
integrated	O
round-trip	B-Application
engineering	I-Application
for	O
JavaScript	O
Classes	O
.	O
</s>
<s>
UML	B-Language
Diagrams	I-Language
are	O
generated	O
with	O
a	O
diagram	O
library	O
JointJS	O
.	O
</s>
