Question

So, to start I have this class:

    public class PaginatedList<?> extends ArrayList<?>{
       private int startIndex;
       private int endIndex;

       public PaginatedList(int startIndex, int endIndex...){
           this.startIndex = startIndex;
           this.endIndex = endIndex;
           //Do pagination stuffs.
       }
    }

and this class:

    public class UserList extends PaginatedList<User>{

       public UserList(int startIndex, int endIndex...){
          super(startIndex, endIndex...);
       }

    }

Now, when I have my resource return a UserList, it prints out the list of users as expected:

[
  {
    "userName":"binky",
    "age":115
  }
]

But, I want the output to be like this:

{
  "users":
   [
     {
       "userName":"binky",
       "age":115
     }
   ],
  "pagination":
   {
     "startIndex":5,
     "endIndex":10
   }
}

So, I annotate both of them with @JSONRootName(“”).

@JsonRootName("pagination")
public class PaginatedList extends ArrayList<?>{}
@JsonRootName("activities")
public class UserList extends PaginatedList<User>{}

and created a class to set up the ObjectMapper:

        @Provider 
        @Produces(MediaType.APPLICATION_JSON)
        public class Resolver implements ContextResolver<ObjectMapper>{

            private ObjectMapper objectMapper;

            public ObjectMapperProvider(){
                objectMapper = new ObjectMapper();
            }

            @Override
            public ObjectMapper getContext(Class<?> type) {
                if(type.getAnnotation(JsonRootName.class) != null){
                         objectMapper.configure(DeserializationConfig.Feature.UNWRAP_ROOT_VALUE, true);
                }else{
                       objectMapper.configure(DeserializationConfig.Feature.UNWRAP_ROOT_VALUE, false);
                }
                return objectMapper;
            }
        }

And still this implementation does not resolve my issue. The marshalled json does not return the unwrapped root values.

I am using jersey POJOMAPPING.

Any ideas?

Answer 1

It seems as though @JsonRootResource is more reserved for properties, not class level declarations. This should create a compilation error, but does not.