Alternative to Jackson @JsonSubTypes in python?

Question

Instead of using a dict to store and pass data we are going completely OOPS approach of storing the data as class attributes. In our json the input and output structure can change.

In JAVA we have jackson library where we can based on json key specify the class

Example:

@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
@JsonSubTypes({
        @JsonSubTypes.Type(value = S1Config.class, name = "S1")}
        @JsonSubTypes.Type(value = S2Config.class, name = "S2")}
)

Wanted to do similar thing in Python and only thing I could think was to use if conditions

class DataModel:
    def __init__(self, data):
        if data["in"]["type"] == "s1":
            self.input = S1Config(data["input"])
        elif data["in"]["type"] == "s2":
            self.input = S2Config(data["input"])
        if data["out"]["type"] == "s1":
            self.output = S1Config(data["output"])

Is there any other better way then what I have implemented?

Answer 1

It might be clearer to use some kind of mapping.

Here is the example

in_out_mappings = {
    's1': S1Config,
    's2': S2Config,
}

class DataModel:
    def __init__(self, data):
        in_type = data['in']['type']
        in_class = in_out_mappings[in_type]

        out_type = data['out']['type']
        out_class = in_out_mappings[out_type]

        self.input = input_class(data['input'])
        self.output = output_class(data['output'])