Standard format for specifying the mapping of fields - interface

Question

We are trying to build a single interface which can be integrated with multiple systems.
Hence we need a way to specify the mappings of standard fields across different systems.
Example:
Interface1 has the following fields: A, B, C
Interface2 has the following fields: P, Q, R
We need to map fields: A -> Q, B -> P and C -> R (just an example)
We can simply create a JSON of such mappings and follow our own convention, but wanted to check if there are any standard formats / open source tools for specifying or simplifying the mapping of fields from source to destination?

Answer 1

Assuming you are trying to convert:
Response from interface 1 = { "A": "value1", "B": "value2", "C": "value3" }
to:
Response from interface 2 = { "Q": "value1", "P": "value2", "R": "value3" }
You can use any library that does JSON transformations such as this or this. For instance, you could define your transformation like this:
var template = {
Q: '$.A',
P: '$.B',
R: '$.C'
};
var input = { "A": "value1", "B": "value2", "C": "value3" };
var output = jsonPathObjectTransform(input, template);
// -> output = { "Q": "value1", "P": "value2", "R": "value3" }
Using Java with Jolt (I was unable to test it, but that's the general idea):
String input = "{\n" +
" \"A\": \"value1\",\n" +
" \"B\": \"value2\",\n" +
" \"C\": \"value3\"\n" +
"}"
String spec = "[\n" +
" {\n" +
" \"operation\": \"shift\",\n" +
" \"spec\": {\n" +
" \"A\": \"Q\",\n" +
" \"B\": \"P\",\n" +
" \"C\": \"R\"\n" +
" }\n" +
" }\n" +
"]\n"
Chainr chainr = JsonUtils.jsonToList(spec);
Object output = chainr.transform(input);
// -> output = { "Q": "value1", "P": "value2", "R": "value3" }