Simple Transformation - handling null values

matt — Thu, 25 Aug 2016 11:56:08 GMT

I have JSON data like:

[

{"NodeId":0,"Name":"ABCD","InstrumentCode":"A2545","ParameterName:"FERR","ParameterID":"PID1"},

{"NodeId":2,"Name":"BGEL","InstrumentCode":"Q436","ParameterName":"GRAPH","ParameterID":"PID3"}

]

In my transformation, I have

<tt:template>

<array>

<tt:loop ref=".VALUES">

<tt:value ref="$ref.nodeid"/>

</num>

<tt:value ref="$ref.name"/>

</str>

<tt:value ref="$ref.instrumentcode"/>

</str>

<tt:value ref="$ref.parametername"/>

</str>

<tt:value ref="$ref.parameterid"/>

</str>

</object>

</tt:loop>

</array>

</tt:template>

And then I deserialise the JSON data using this ABAP:

DATA: BEGIN OF value,

nodeid TYPE i,

name TYPE c LENGTH 255,

instrumentcode TYPE c LENGTH 255,

parametername TYPE c LENGTH 255,

parameterid TYPE c LENGTH 255,

END OF value.

DATA values LIKE STANDARD TABLE OF value WITH EMPTY KEY.

CALL TRANSFORMATION my_Transformation SOURCE XML my_json_data RESULT values = values.

The problem I have, is that within my data, I have some entries like this:

{"NodeId":12,"Name":"BGRT","InstrumentCode":"A436","ParameterName":null,"ParameterID":"PID3"}

With this, I get a ST_MATCH_FAIL dump, with the information:

The reason for the exception is:

XML comparison error

Expected element-start: "str" [ ] Read element-start: "null" [ ].

How do I construct a conditional (I guess using tt:switch and tt:d-cond) in my transformation, to handle when the ParameterName is not a string, but is null? I want to skip any null values.

Re: Simple Transformation - handling null values

retired_member — Thu, 25 Aug 2016 12:28:03 GMT

Hi Matthew,

in JSON-XML, that is the interface between JSON and ABAP, the null values of JSON are represented as separate elements

Json null → XML <null />

I guess you must react on <null /> in your trafo.

Horst

Re: Simple Transformation - handling null values

matt — Fri, 26 Aug 2016 08:27:42 GMT

Figured it out. For example:

<tt:switch>

<tt:d-cond using="type-C($ref.parametername)">

<tt:value ref="$ref.parametername"/>

</str>

</tt:d-cond>

<tt:d-cond>

<tt:value ref="$ref.parametername"/>

</null>

</tt:d-cond>

</tt:switch>

In this way, if the parametername has a value, the first condition is carried out. If it is null, the second is executed. I don't know if there is a better way, but this works!

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Simple Transformation - handling null values

Re: Simple Transformation - handling null values

Re: Simple Transformation - handling null values