Dataweave Error for Null nodes

Question

I have done coding in dataweava as

%dw 1.0
%input payload application/xml
%output application/xml skipNullOn="everywhere"
---
{((payload.*Order default []) map {
Order:{
    Channel:$.@EnterpriseCode,
    Code:$.@OrderNo,
    Status:$.@Status,
    OrderLines: {
    (($.OrderLines.*OrderLine default []) map {
    OrderLine:{
        EntryNumber:"abc",
        Status:$.@Status,

        (($.OrderStatuses.*OrderStatus default []) map {

        ShipDate:$.@StatusDate

        }) 
    }})}
}

}
)
}

But its giving error when assigning input as

<?xml version="1.0" encoding="UTF-8"?>
<Order EnterpriseCode="111" OrderNo="222" Status="Scheduled">
    <OrderLines>
        <OrderLine PrimeLineNo="2" Status="Shipped" OrderedQty="1000">

        </OrderLine>
    </OrderLines>
</Order>

Any suggestions here? I have tried default [] but its not working. When assigning null node its giving error. I have tried filter as filter ($ != '')

What error is it giving? Is it `Cannot coerce a :null to a :array (com.mulesoft.weave.mule.exception.WeaveExecutionException). Message payload is of type: LinkedList` ? — Möoz, Dec 01 '15 at 22:32

DavoCoder · Accepted Answer · 2015-11-30T20:26:05.753

XML input example:

<?xml version="1.0" encoding="UTF-8"?>
<Order EnterpriseCode="111" OrderNo="222" Status="Scheduled">
  <OrderLines>
    <OrderLine PrimeLineNo="2" Status="Shipped" OrderedQty="1000">
       <OrderStatuses>
          <OrderStatus StatusDate="statusDate"></OrderStatus>
          <OrderStatus StatusDate="statusDate"></OrderStatus>
      </OrderStatuses>
    </OrderLine>
    <OrderLine PrimeLineNo="3" Status="Shipped3" OrderedQty="10003" ></OrderLine>
  </OrderLines>
</Order>

Note: In your example there are spaces between OrderLine open tag and close tag, you have to fix it:

<OrderLine PrimeLineNo="3" Status="Shipped3" OrderedQty="10003" ></OrderLine>

Dataweave script:

%input payload application/xml
%output application/xml skipNullOn="everywhere"
---
{
  ((payload.*Order default []) map {
    Order:{
      Channel:$.@EnterpriseCode,
      Code:$.@OrderNo,
      Status:$.@Status,

      OrderLines: {
        (($.OrderLines.*OrderLine default []) map {

          OrderLine:{
            EntryNumber:"abc",
            Status:$.@Status, 

            (($.OrderStatuses.*OrderStatus default []) map ((key,pos) -> {
                ShipDate:key.@StatusDate
            }) when $!='' otherwise {})

          }

        })
      }


    }
  })
}

You can't map a value if it doesn't exist, so you have to use "when/otherwise" to verify the existence of the elements.

Hi Davo, In tried this code, but it still giving error by providing this input ` ` — Rohan Shinde, Nov 26 '15 at 04:26
Ok, I built the script with an empty OrderLine like this: with the inline close tag. — DavoCoder, Nov 26 '15 at 14:10
Is there any other option for the input that I have provided? — Rohan Shinde, Nov 27 '15 at 05:31
Yeah Its working.. But again If anybody have different requirement it will change according to that. Thanks Davo — Rohan Shinde, Dec 01 '15 at 07:36
+1 for 'You can't map a value if it doesn't exist' , when you have a typo in the field names, this is the error message you will get : `Cannot coerce a :null to ...` — mcvkr, Sep 15 '17 at 20:47

score 0 · Answer 2 · answered Nov 27 '15 at 08:34

Try this: This should solve your issue. (Unless not/otherwise) or (when/otherwise), any combination can be used as per your requirement. "Unless not" is recommended if ShipDate is present in most cases, else replace "unless not" with "when".

%dw 1.0
%input payload application/xml
%output application/xml skipNullOn="everywhere"
---
{
(
    (payload.*Order default []) map {
        Order: {
            Channel:$.@EnterpriseCode,
            Code:$.@OrderNo,
            Status:$.@Status,
            OrderLines: {
                (
                    ($.OrderLines.*OrderLine default []) map ({
                        OrderLine: {
                            EntryNumber:"abc",
                            Status:$.@Status,
                            (
                                ($.OrderStatuses.*OrderStatus) map {
                                    ShipDate:$.@StatusDate
                                }
                            )
                        }
                    }) unless not $.OrderLines.*OrderLine.OrderStatuses? otherwise {
                        OrderLine: {
                            EntryNumber:"abc",
                            Status:$.@Status                                
                        }
                    }
                )
            }
        }
    }
)
}

Hi J J, this code looks good as working for single iteration ` ` But Is code fails for iterative elements of orderline — Rohan Shinde, Nov 27 '15 at 09:32

score 0 · Answer 3 · edited Jan 30 '18 at 21:13

0

Try following approaches:

use "SkipNullOn" %output application/xml skipNullOn="everywhere"
You can use when condition as shown below yourField: "null" when

payload.yourField == null otherwise payload.yourField

edited Jan 30 '18 at 21:13

Jason Aller

3,541
28
38
38

answered Jan 30 '18 at 20:53

Rajnish Kumar Jha

11
3

score 0 · Answer 4 · answered Feb 26 '18 at 06:32

Giving below the structure definition of Mule Message Object has Message Inbound Property Outbound Property Payload Variable Flow Variable Session Variable Attachment Exception Payload

When a connector of a flow (listening on a port) receives the payload its called Inbound endpoint. When in a flow we have a connectore placed in the middle and send a payload its called Oubound endpoint. Here the all the outbound properties sent to the Http Outbound flow become Inbound Properties within that flow.

For detailed explanation see the link below.

https://docs.mulesoft.com/mule-user-guide/v/3.8/mule-message-structure.

Dataweave Error for Null nodes

4 Answers4