How to handle multiple type of json in one parser class?

Question

I am expecting two separate jsons in case of success and failure.

In case of success I get a nested json whereas in failure I get a simple json mentioning status : failed so my class I used to handle success is failing for failure scenario. Can someone please guide here? Only way I can think in checking the substring of json and validate before parsing but that doesn't seem a good solution.

Updated Jsons: Success:

{
    "Subscriptions": [
        {
            "Subscription": {
                "SAPOrder": "SAP123",
                "RequestType": "New",
                "OrderStatus": "0",
                "Services": [
                    {
                        "Service": [{
                            {
                                "attribute": {
                                    "name": "Resilience",
                                    "value": "Terminated"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "Number",
                                    "value": "1234"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "serviceStartDate",
                                    "value": "2018-08-220T02:13:20"
                                }
                            }
                        },
                            {{
                                "attribute": {
                                    "name": "Resilience",
                                    "value": "Terminated"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "Number",
                                    "value": "1234"
                                }
                            },
                            {
                                "attribute": {
                                    "name": "serviceStartDate",
                                    "value": "2018-08-220T02:13:20"
                                }
                            }
                        }
                        ]
                    }
                ]
            }
        }
    ]
}

Failure:

  {
        "Subscriptions": [
            {
                "Subscription": {
                    "SAPOrder": "SAP123",
                    "RequestType": "New",
                    "OrderStatus": "Failed"
                }
            }

Added Class details:

public class JSON2Apex {

    public class Services {
        public List<Service> Service;
    }

    public List<Subscriptions> Subscriptions;

    public class Attribute {
        public String name;
        public String value;
    }

    public class Subscriptions {
        public Subscription Subscription;
    }

    public class Service {
        public List<Attribute> attribute;
    }

    public class Subscription {
        public String SAPOrder;
        public String RequestType;
        public String OrderStatus;
        public List<Services> Services;
    }


    public static JSON2Apex parse(String json) {
        return (JSON2Apex) System.JSON.deserialize(json, JSON2Apex.class);
    }
}

Answer 1

You don't need to do anything extra here. As I see in your responses, you still have all attributes in the error JSON except for the array of Services, which you get only in success.

"Subscription": {
       "SAPOrder": "SAP123",
       "RequestType": "New",
       "OrderStatus": "0",
}

So as long as your wrapper class is in the below format:

public class SubscriptionWrapper {
    public Subscription subscription;
    ....
}

public class Subscription {
    public String SAPOrder;
    public String RequestType;
    public String OrderStatus;
    public List<Services> services
}

And that you receive the error vs. success on the OrderStatus variable, while deserializing your response, you get only what's in the JSON. If the List<Services> is present in the JSON in case of success, you get that too when you deserialize, else not.

And then you use the OrderStatus value to determine if you received a success vs. error message and use it accordingly as required.

As an example, the below code will work without any issue whether or not you have all the attribtues in the JSON message or not.

String jsonStr = '{\"OrderStatus\": \"Success\"}';

Subscription subsc = (Subscription)JSON.deserialize(jsonStr, Subscription.class);
system.debug('Order Status:' + subsc.OrderStatus);

Answer 2

you can create virtual class to have status of your request, and after that you can extend this class with another one containing success answer fields. E.g.

public virtual class BaseResponse {
    public String status {get; set;}
    public String error {get; set;}
}

---

public class YourResponse extends BaseResponse {
    public List<String> yourDate {get; set;}
}

---

after that you can parse response in the following way:

YourResponse response = (YourResponse) JSON.deserialize(body, YourResponse .class);
if(response.status == 'success'){
    // do actions on success
} else if(response.status == 'failed'){
    // whos error message e.g. response.error
}

this virual class allows you to create other classes, that also have this success-fail responses