Handling gson with dynamic array and Object

Question

I am getting response from API, in that if there is data present then it is returning object and when data is not present it is returning blank array. I have model class for serializing this. Here is model class

    @SerializedName("local")
    public Local _local  = new Local();     
     public class Local{
      @SerializedName("total")
            public String _total;

            @SerializedName("providers")
            public  ArrayList<ProvidersDetails> _providers = new ArrayList<>();

            public class ProvidersDetails{
                @SerializedName("id")
                public String _id;

                @SerializedName("image")
                public String _image;

            }

            @SerializedName("admin")
            public transient Admin admin = new Admin();

            public class Admin{

               @SerializedName("id")
                public String _id;

                @SerializedName("first_name")
                public String _first_name;

                @SerializedName("last_name")
                public String _last_name;

            }

           @SerializedName("orgn")
            public Organization _organization = new Organization();

            public class Organization{
                @SerializedName("name")
                public String _ name;
            }
        }

Here is some part of response i am getting from api

       "local":{
       "providers":[
        {
        "id":"1180",  
       "image":"photo.png"
        },
         {
        "id":"1180",  
       "image":"photo.png"
         },
         {
        "id":"1180",  
       "image":"photo.png"
        }
        ],
       "admin":{
       "id":"1180",
      "first_name":"nqgnerq",
       "last_name":"gnejbeqp",
      },
     "orgn":{
      "name":"organization name"
      }
      }

here is the other form which i am getting when data is not present

     "local":{
     "total":0,
     "providers":[
     ],
     "admin":[
      ],
    "orgn":{
      "name":"organization name"
      }
     }

I have checked many work arounds but failed, as i want to handle it in my pojo class. DO any one have solution, please suggest.

Answer 1

You can handle it with "JsonDeserializer" .Here is an example. Make class ProvidersDetails implements Serializable

Create a new class like this

public class ProvidersDetailsList {
    public ArrayList<ProvidersDetails> getDetails() {
        return providersDetails;
    }

    ArrayList<ProvidersDetails> providersDetails= new ArrayList<>();
}

Now write the Deserializer.

 public class PhotoAlbumDeserializer implements JsonDeserializer {

        @Override
        public Object deserialize(JsonElement jsonElement, Type type, JsonDeserializationContext jsonDeserializationContext) throws JsonParseException {
            ProvidersDetailsList providersDetailsList= new ProvidersDetailsList ();

            JsonObject jsonObject = jsonElement.getAsJsonObject();
            if (jsonObject != null) {

                JsonElement usersField = jsonElement.getAsJsonObject().get("providers");
                if (usersField == null || usersField.isJsonNull() || usersField.isJsonPrimitive())
                    ; // if is null or is a primitive type will return an empty result
                else if (usersField.isJsonObject()) {
                    providersDetailsList.getDetails().add((ProvidersDetails) jsonDeserializationContext.deserialize(usersField, ProvidersDetails.class));

                } else if (usersField.isJsonArray()) {
                    Type listOfUserType = new TypeToken<List<ProvidersDetails>>() {
                    }.getType();
                    providersDetailsList.getDetails().addAll((Collection<? extends ProvidersDetails>) jsonDeserializationContext.deserialize(usersField, listOfUserType));
                }

            }
            return providersDetailsList;
        }
    }

Now call it like this

GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(ProvidersDetailsList.class, new PhotoAlbumDeserializer());
Gson gson = gsonBuilder.create();
ArrayList<ProvidersDetails> providersDetails = gson.fromJson(jsonString, ProvidersDetailsList.class);

Here is a link to do it with Gson https://stackoverflow.com/a/16591621/3111083