Reviewing a Complex DataWeave Transformation Use-case v2

1. Alexandra Martinez
Reviewing a Complex DataWeave
Transformation Use-case

2. 2
● Functions (fun)
○ Parameters using types
○ Calling functions with 2 parameters
● Variables (var)
● do statement to create scopes (local variables)
● Object manipulation using object destructor {( )}
● If/else
● Selectors:
○ Index (array[0])
○ Range (1 to 10)
● Setting default values
● Core functions/operators
○ isEmpty, reduce, map, groupBy, flatten
○ Remove (-), Sum (+), Concatenation (++), Prepend (>>)
Solution will make use of the following:

3. Requirement

4. 4
Input JSON structure to Output JSON structure
Requirement

5. 5
● Logic:
1. For each object from the
FlightOptions array, create one
output object inside the output array.
Requirement
5

6. 6
● Logic:
1. For each object from the
FlightOptions array, create one
output object inside the output array.
2. The AppliedTaxCode will contain the
value from the last Connection
object.
Requirement
6

7. 7
● Logic:
1. For each object from the
FlightOptions array, create one
output object inside the output array.
2. The AppliedTaxCode will contain the
value from the last Connection
object.
3. If the EndOfConnection field is true,
create a separate output object.
Requirement
7

8. 8
● Logic:
1. For each object from the
FlightOptions array, create one
output object inside the output array.
2. The AppliedTaxCode will contain the
value from the last Connection
object.
3. If the EndOfConnection field is true,
create a separate output object.
4. If there are EndOfConnection fields
that are true and this is not the last
object inside the Connections array,
create a new output object
containing all the false Connection
objects before this, and using this
last object’s TaxCode.
Requirement
8

9. 9
● Logic:
1. For each object from the
FlightOptions array, create one
output object inside the output array.
2. The AppliedTaxCode will contain the
value from the last Connection
object.
3. If the EndOfConnection field is true,
create a separate output object.
4. If there are EndOfConnection fields
that are true and this is not the last
object inside the Connections array,
create a new output object
containing all the false Connection
objects before this, and using this
last object’s TaxCode.
5. Each AppliedConnections object in
the output must have:
1. A hardcoded Type value
“Connection”.
Requirement
9

10. Building the Solution

11. 11
● DW Playground: https://dwl.mule.club/
● Input payload:
{"FlightOptions":[{"Connections":[{"ReferenceID":111,"TaxCode":"ABC","EndOfConnection":false},{"ReferenceID":222,"TaxCode":"DEF","EndOfConnection":true}]},{"
Connections":[{"ReferenceID":333,"TaxCode":"GHI","EndOfConnection":true},{"ReferenceID":444,"TaxCode":"JKL","EndOfConnection":true}]},{"Connections":[{"Ref
erenceID":555,"TaxCode":"MNO","EndOfConnection":false},{"ReferenceID":666,"TaxCode":"PQR","EndOfConnection":false},{"ReferenceID":777,"TaxCode":"STU","
EndOfConnection":false}]},{"Connections":[{"ReferenceID":888,"TaxCode":"VWX","EndOfConnection":false}]},{"Connections":[{"ReferenceID":999,"TaxCode":"MNO"
,"EndOfConnection":false},{"ReferenceID":101,"TaxCode":"PQR","EndOfConnection":true},{"ReferenceID":102,"TaxCode":"STU","EndOfConnection":false}]}]}
● Expected output:
[{"AppliedTaxCode":"DEF","AppliedConnections":[{"Type":"Connection","IndexValue":1},{"Type":"Connection","IndexValue":2}]},{"AppliedTaxCode":"GHI","AppliedCo
nnections":[{"Type":"Connection","IndexValue":3}]},{"AppliedTaxCode":"JKL","AppliedConnections":[{"Type":"Connection","IndexValue":4}]},{"AppliedTaxCode":"STU
","AppliedConnections":[{"Type":"Connection","IndexValue":5},{"Type":"Connection","IndexValue":6},{"Type":"Connection","IndexValue":7}]},{"AppliedTaxCode":"VW
X","AppliedConnections":[{"Type":"Connection","IndexValue":8}]},{"AppliedTaxCode":"PQR","AppliedConnections":[{"Type":"Connection","IndexValue":9},{"Type":"C
onnection","IndexValue":10}]},{"AppliedTaxCode":"STU","AppliedConnections":[{"Type":"Connection","IndexValue":11}]}]
● Format JSONs:
https://jsonformatter.curiousconcept.com/
Building the Solution

12. 12
1) Extract the Connections arrays.
Building the Solution

13. 13
2) Change all the EndOfConnection to true for the last Connection object from the Connections
array.
Building the Solution

14. 14
3) flatten the array of arrays to be just one array.
Building the Solution

15. 15
4) Add a new field to keep track of the object’s index, basing on the EndOfConnection field.
(For each EndOfConnection=true, stop incrementing the index.)
Building the Solution
Index 1
Index 2
Index 1
Index 1
Index 1
Index 3
Index 2

16. 16
5) Add a new field to keep track of the final AppliedConnections object’s (first) index where the
object in question will be added.
Note: This is calculated using the object’s index + 1 (to start at 1) and then minus the previously
added indexBasedOnEOC field.
Building the Solution
Index 0
Index 2
Index 3
Index 4

17. 17
6) Separate the objects based on the EndOfConnection value (true or false).
Building the Solution

18. 18
7) Take only the objects that are inside the “true” list.
Building the Solution

19. 19
8) Create the final output.
Building the Solution

20. Playing with the indexes

21. 21
Playing with the indexes
1
2
1
1
1
2
3
1
1
1
2
Index based on
EndOfConnection

22. 22
Playing with the indexes
Index based on
EndOfConnection index + 1
1
3
4
5
2 6
7
8
9
10
11
1
2
1
1
1
2
3
1
1
1
2

23. 23
Playing with the indexes
Index based on
EndOfConnection
1-1=0
3-1=2
4-1=3
5-1=4
2-2=0 6-2=4
7-3=4
8-1=7
9-1=8
10-2=8
11-1=10
1
2
1
1
1
2
3
1
1
1
2
AppliedConnections
Index
(index+1) - indexBasedOnEOC

24. 24
Playing with the indexes
Index based on
EndOfConnection
0
2
3
4
0 4
4
7
8
8
10
1
2
1
1
1
2
3
1
1
1
2
1+0=1
2+0=2
1+2=3
1+3=4
1+4=5
2+4=6
3+4=7
1+7=8
1+8=9
2+8=10
1+10=11
AppliedConnections
Index
(index+1) - indexBasedOnEOC
IndexValue
indexBasedOnEOC (or actualIndex or
actualNum) +
indexAppliedConnections

25. Try it yourself!

26. Code
● GitHub repository: https://github.com/alexandramartinez/reviewing-a-complex-dw-
transformation-use-case/

27. References
● https://docs.mulesoft.com/mule-runtime/4.3/dataweave-functions
● https://docs.mulesoft.com/mule-runtime/4.3/dataweave-variables
● https://docs.mulesoft.com/mule-runtime/4.3/dataweave-flow-control
● https://docs.mulesoft.com/mule-runtime/4.3/dataweave-selectors
● https://docs.mulesoft.com/mule-runtime/4.3/dataweave-cookbook-defaults
● https://docs.mulesoft.com/mule-runtime/3.9/dataweave-operators
● https://docs.mulesoft.com/mule-runtime/4.3/dw-operators
● https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-isempty
● https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-reduce
● https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-map
● https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-groupby
● https://docs.mulesoft.com/mule-runtime/4.3/dw-core-functions-flatten

28. Questions?