在Dataweave中处理NULL xml节点

Question

How can I access the body and/or avoid error of NULL values in xml nodes in mule data weave.

Consider this is my node:

<catalog>
    <product product-id="D158413" mode="delete"/>
    <product product-id="556204380">
    <ean>5014414203648</ean>
    <display-name>Double duvet cover</display-name>
    <long-description>Line</long-description>
    <online-flag>true</online-flag>
    <available-flag>true</available-flag>
    <searchable-flag>true</searchable-flag>
    <tax-class-id>default</tax-class-id>
    <brand>Linea</brand>
    <manufacturer-name>Linea</manufacturer-name>
    <custom-attributes>
        <custom-attribute attribute-id="Care Instructions">Machine</custom-attribute>
        <custom-attribute attribute-id="Colour">Pink</custom-attribute>
        <custom-attribute attribute-id="Finish">Plain</custom-attribute>
        <custom-attribute attribute-id="Guarantee">N/A</custom-attribute>
    </product>  
</catalog>

My Dataweave Code is :

%dw 1.0
%input payload application/xml
%output application/java 
---
(payload.catalog.*product default []) map  {
    CatalogDetails:{
            CatalogId:payload.catalog.@catalog-id
    },
    ProdDetails:{
                product-id:$.@product-id,
                mode:$.@mode,
                ean:$.ean,
                upc:$.upc,
                min-order-quantity:$.min-order-quantity,    
                display-name:$.display-name,
                short-description:$.short-description
    },
CustValues: { (
            ($.custom-attributes.*custom-attribute default []) map {      
                (sellByUnitVal: $)  when ($.@attribute-id) == "sellByUnit" ,
                (VOLUMEVal: $) when ($.@attribute-id) == "VOLUME",
                (UnitMeasureVal: $) when ($.@attribute-id) == "UnitMeasure"
             } 
        ) }
   }

The first Product node doesn't receive a body. I tried using default [] but it's not working. How can I make sure it always receives a body?

Answer 1

Your XML example isn't complete and valid, missing and upc values etc. that you are using in your DataWeave script.

Your solution is probably something like checking the sizeOf the node, and if it's 0 fill it op with a whitespace, if not execute your normal script.

If you have your complete examples that would help.

Answer 2

I have found out one way to handle the empty nodes as, we can use filter to skip the empty nodes,

(payload.catalog.*product default []) filter ($ !='') map { }

Using this we control the empty or non empty tags into the transformation.