Information Technology Reference
In-Depth Information
After the decision node is introduced, no matter which case is
satisfied, we draw connectors from it to
n
p
1
,
n
p
2
,
...
, and
n
pn
(corre-
sponding to the services designated), respectively. Meanwhile, set
the corresponding guard (
C
1
;
C
n
) for these control flows.
Then we introduce a merge node into the diagram, whose inputs
originate from
n
p
1
,
n
p
2
,
...
, and
n
pn
, respectively. After that we
compute the corresponding state
S
M
of merge node
n
M
, and add
n
M
into
NS
to complete the connection with
C
2
; ...;
. The merge node is also
with a state for reasoning here for the simplicity of our algorithm.
If none of these three cases is met, the multiple branch structure
cannot be introduced into the diagram at present.
For Type III preference:
WS
1
SCP
WS
2
...
WS
n
. First, for
types of
WS
1
WS
2
, algorithm PPP is proposed as follows.
Algorithm PPP. Processing Preference with Priority
1.
w
0
;
w
00
g
V
ð
S
0
Þ then
if f
Suppose
n
0
A
;
n
0
A
2
2.
NS
temp
representing two action nodes
corresponding to service
w
0
and
w
00
with states
S
0
A
and
S
0
A
,
respectively;
3. Introduce a decision node into the diagram, and draw a
connector from
n
0
A
to it;
4. Draw a connector from the decision node to
n
0
A
, set a guard
along this new connector with the condition “Fail”, and delete
the original connector pointed to it;
5. Introduce a merge node
n
M
into the diagram, draw a connector
from action node
n
0
A
to it; then draw a connector from the
decision node to it, meanwhile, set a guard along this new
connector with the condition “Succeed”; compute the corre-
sponding state
S
M
of
n
M
;
6.
NS
n
0
A
;
n
0
A
g[f
¼
NS
f
n
M
g
;
7.
end if
Similar to procedure PPCE, once the services included in user
preferences appear, we begin to introduce a conditional branch structure
into the activity diagram that is being constructed. However, the situation
is much simpler here. After detecting that two services (
w
0
and
w
00
)canbe
executed, a decision node is introduced into the diagramdirectly. Its input
comes from the action
n
0
A
, the corresponding action of service
w
0
that has
