1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152

--- This module defines a bi-directional BPMN to BPEL transformation

{-# OPTIONS_CYMAKE -Wno-incomplete-patterns -Wno-overlapping #-}

module BPMN2BPEL where

import Grappa


--- The type of BPMN edges.
data BPMNComp =
     BPMNStart | BPMNEnd | BPMNPGW |
     BPMNXGW String String |        --XOR conditions as params
     BPMNActivity String |          --label as param
     BPMNInter BPMNInterKind String --kind and label as params

data BPMNInterKind = BPMNWait | BPMNReceive

--- An exampe BPMN graph.
ex :: Graph BPMNComp
ex = [(BPMNStart,[1]),(BPMNPGW,[1,2,4,3]),(BPMNActivity "act1",[2,6]),
      (BPMNActivity "act2",[6,10]),(BPMNPGW,[15,16,18,17]),
      (BPMNActivity "act3",[3,5]),(BPMNXGW "cond1" "cond2",[5,7,9,8]),
      (BPMNActivity "act4",[7,11]),(BPMNActivity "act5",[8,14]),
      (BPMNInter BPMNWait "ev2",[11,13]),(BPMNXGW "" "",[12,13,17,14]),
      (BPMNInter BPMNReceive "ev1",[10,16]),(BPMNEnd,[18])]


-------------------------------------------------------------------------
-- A significant subset of BPEL:

--- The type of activities of a BPEL process.
data BPELComp = Invoke String | Wait String | Receive String |
                Flow BPEL BPEL | Switch String String BPEL BPEL

--- Sequences of activities of a BPEL process.
type BPEL = [BPELComp]

--- The main parsing operation.
--- The parser works on typed hypergraphs with edges of type `BPMNComp`
--- and returns a semantic value of type `BPEL` (the BPEL corresponding
--- to the input BPMN).
processS :: Grappa BPMNComp BPEL
processS = edge (BPMNStart,[n1]) *>
           flowS (n1,n2) <*
           edge (BPMNEnd,[n2])
 where n1,n2 free

flowS :: (Node,Node) -> Grappa BPMNComp BPEL
flowS (n1,n2) = (:[]) <$> flElemS (n1,n2)
flowS (n1,n2) = (:)   <$> flElemS (n1,n) <*> flowS (n,n2)
                where n free

flElemS :: (Node,Node) -> Grappa BPMNComp BPELComp
flElemS (n1,n2) = translateInter itype name <$
                  edge (BPMNInter itype name, [n1,n2])
                  where itype,name free
                        translateInter BPMNWait    = Wait
                        translateInter BPMNReceive = Receive
flElemS (n1,n2) = Invoke lab <$
                  edge (BPMNActivity lab, [n1,n2])
                  where lab free
flElemS (n1,n2) = edge (BPMNPGW, [n1,n1t,n1r,n1b]) *>
                  (Flow <$>
                   flowS (n1t,n2t) <*>
                   flowS (n1b,n2b)) <*
                  edge (BPMNPGW, [n2l,n2t,n2,n2b])
                  where n1t,n1r,n1b,n2l,n2t,n2b free
flElemS (n1,n2) = edge (BPMNXGW c1 c2, [n1,n1t,n1r,n1b]) *>
                  (Switch c1 c2 <$>
                   flowS (n1t,n2t) <*>
                   flowS (n1b,n2b)) <*
                   edge (BPMNXGW d1 d2, [n2l,n2t,n2,n2b])
                  where c1,c2,d1,d2,n1t,n1r,n1b,n2l,n2t,n2b free



--- Shows a BPEL as a string in XML format.
bpel2xml :: BPEL -> String
bpel2xml f = "<process>\n" ++
                 indent 1 (seq2xml f) ++
             "</process>\n"

seq2xml :: [BPELComp] -> String
seq2xml [e] = bpelComp2xml e
seq2xml es@(_:_:_) = "<sequence>\n" ++
                         indent 1 (concatMap bpelComp2xml es) ++
                     "</sequence>\n"

bpelComp2xml :: BPELComp -> String
bpelComp2xml (Invoke name) = "<invoke name=\""++name++"\"/>\n"
bpelComp2xml (Wait name) = "<wait name=\""++name++"\"/>\n"
bpelComp2xml (Receive name) = "<receive name=\""++name++"\"/>\n"
bpelComp2xml (Flow f1 f2) = "<flow>\n" ++
                                indent 1 (seq2xml f1) ++
                                indent 1 (seq2xml f2) ++
                            "</flow>\n"
bpelComp2xml (Switch c1 c2 f1 f2) =
                            "<switch>\n" ++
                            " <case cond=\""++c1++"\">\n" ++
                                indent 1 (seq2xml f1) ++
                            " </case>\n" ++
                            " <case cond=\""++c2++"\">\n" ++
                                indent 1 (seq2xml f2) ++
                            " </case>\n" ++
                            "</switch>\n"

indent :: Int -> String -> String
indent n s = unlines (map (nblanks++) (lines s))
 where nblanks = take n (repeat ' ')

{-
Usage:

Transform our example graph into BPEL:

BPMN2BPEL> processS ex
([Flow [Invoke "act1",Invoke "act2",Receive "ev1"] [Invoke "act3",Switch "cond1" "cond2" [Invoke "act4",Wait "ev2"] [Invoke "act5"]]],[])

Generating graphs:

BPMN2BPEL Grappa> (processS <* eoi) [e1,e2,e3] where e1,e2,e3 free

Reverse the transformation:

BPMN2BPEL> processS [e1,e2,e3,e4] =:= ([Invoke "act1",Wait "ev1"],[])  where e1,e2,e3,e4 free
{e1=(BPMNStart,[_a]), e2=(BPMNActivity "act1",[_a,_b]), e3=(BPMNInter BPMNWait "ev1",[_b,_c]), e4=(BPMNEnd,[_c])} True

BPMN2BPEL> processS [e1,e2,e3,e4,e5,e6] =:= ([Switch "c1" "c2" [Invoke "act1"] [Invoke "act2"]],[]) where e1,e2,e3,e4,e5,e6 free 
{e1=(BPMNStart,[_a]), e2=(BPMNXGW "c1" "c2",[_a,_b,_c,_d]), e3=(BPMNActivity "act1",[_b,_e]), e4=(BPMNActivity "act2",[_d,_f]), e5=(BPMNXGW _g _h,[_i,_e,_j,_f]), e6=(BPMNEnd,[_j])} True

-}