Array to flat mapping in Mule based on condition

Question

I am attempting to map a response from a 3rd party call into a different structure using the DataMapper transform within Mule.

From the 3rd party we receive an array of items (amongst other things) and I want to map a single item within the array to an object (JSON). I receive an identifier for the item in the request which is available as an input argument.

My question is, how can I map the fields of the item based on the identifier?

Example XML response


    1234567
    
        
            1
            Sample title1
            21-03-16
        
        
            2
            Sample title2
            21-03-16
        
        
            3
            Sample title3
            21-03-16

Needs to become:

{
    "person": {
        "accountNumber": 1234567,
        "selectedBook": {
            "id": 1, 
            "title": "Sample title1"
        },
        "otherBooks": [
            {
                "id": 2, 
                "title": "Sample title2"
            },
            {
                "id": 3, 
                "title": "Sample title3"
            }
        ]
    }
}

The id of the book selected is held in an inputArgument.bookId.

I can complete the mapping using an xpath rule for each of the fields, however, I have to hardcode the bookId in the xpath. Instead, I need to be able to substitute the actual id for the one provided (and available in the inputArgument).

xpath for title

/account/books/book[child::id=1]/title

I have tried adding MEL to replace the id and various other fixes but nothing seems to work. Is there a way to substitute the bookId field.

Note: Due to client restrictions, I cannot use DataWeave.

user_8548857 · Answer

You should use the Group By operation to transform your XML file into required JSON format. you can do something like this:

Example of DataWeave Transformation:

%dw 1.0
%output application/dw
---
classrooms: payload.school.teachers groupBy $.subject mapObject ((teacherGroup, subject) -> {
    class: {
      name: subject,
      teachers: { (teacherGroup map {
        teacher:{
            name: $.name,
            lastName: $.lastName
        }
      }) },
      attendees: { (payload.school.students filter ($.*hobby contains subject) map {
        attendee: {
          name: $.name,
          lastName: $.lastName
        }
      }) }
    }
})

user_10319452 · Answer

In Case of Mule in case of single XML element convert to Array 

xml files : 

10120

IN Rule file use double dot($..usrId) instead ofsinfle ($.usrId) it will revert array element for single element.

RULE FILE:

Array to flat mapping in Mule based on condition

3 Answers