Field with multiple types

Some fields can hold different types depending on context (e.g. Object data that is sometimes a User, sometimes a List<User>). EasyYapi does not have a field.type rule — use json.rule.convert to rewrite the field's type, or override the return type at the method level.

Convert a specific type to another

Use json.rule.convert to replace a type with a different one. The left side matches the type name; the right side is the replacement canonical name:

# Treat DynamicField as Object
json.rule.convert=groovy:it.type().name()=="com.example.DynamicField" => java.lang.Object

# Treat a raw Map field as a concrete DTO
json.rule.convert=groovy:it.type().name()=="java.util.Map" && it.name()=="data" && it.containingClass().name()=="com.example.Response" => com.example.User

Conditional conversion with filters

json.rule.convert accepts filters so the rule only fires for specific fields:

# Only convert the "data" field of Response
json.rule.convert[groovy:it.containingClass().name()=="com.example.Response" && it.name()=="data"]=groovy:"com.example.User"

Override the response type

If the field is the entire response payload (e.g. Response<Object> where Object should be User), override the return type with method.return:

method.return=groovy:"com.example.Response<com.example.User>"

Example

public class Response<T> {
    private T data;
    private int code;
    private String message;
}

// Method returns Response<User> — EasyYapi expands `data` as User automatically.
@GetMapping("/user/{id}")
public Response<User> getUser(@PathVariable Long id) {}