I have my output structure in COBOL - from which I try to generate to a JSON structure through DFHJS2LS - IBM tools. All the fields change to be required - this giving trouble when generating classes in .Net as all the fields are not present.
Question: How and where (in COBOL or DFHJS2LS) to define fields as optional in order to get them generated properly avoiding null pointer exception.
According to the documentation you can define your COBOL data items with...
data description OCCURS n TIMES
...and use mapping level 4.1 or higher and specify TRUNCATE-NULL-ARRAYS = ENABLED. There is a reference to "structured arrays" which I take to mean you would need to do something like...
05 Something Occurs 1 Times.
10 Something-Real PIC X(8).
...so you get...
"type":"array"
"maxItems":1
"minItems":0
"items":{ ... }
You could also specify mapping level 4.0 or higher and use...
data description OCCURS n TO m TIMES DEPENDING ON t
...to obtain...
"field-name":{
"type":"array",
"maxItems":m
"minItems":n
"items":{ ... }
}`