Using Enums while parsing JSON with GSON

Question

This is related to a previous question that I asked here earlier

JSON parsing using Gson

I am trying to parse the same JSON, but now I have changed my classes a little bit.

{     "lower": 20,     "upper": 40,     "delimiter": " ",     "scope": ["${title}"] } 

My class now looks like:

public class TruncateElement {     private int lower;    private int upper;    private String delimiter;    private List<AttributeScope> scope;     // getters and setters }   public enum AttributeScope {      TITLE("${title}"),     DESCRIPTION("${description}"),      private String scope;      AttributeScope(String scope) {         this.scope = scope;     }      public String getScope() {         return this.scope;     } } 

This code throws an exception,

com.google.gson.JsonParseException: The JsonDeserializer EnumTypeAdapter failed to deserialized json object "${title}" given the type class com.amazon.seo.attribute.template.parse.data.AttributeScope at  

The exception is understandable, because as per the solution to my previous question, GSON is expecting the Enum objects to be actually be created as

${title}("${title}"), ${description}("${description}"); 

But since this is syntactically impossible, what are the recommended solutions, workarounds?

Answer 1

I want to expand a bit NAZIK/user2724653 answer (for my case). Here is a Java code:

public class Item {     @SerializedName("status")     private Status currentState = null;      // other fields, getters, setters, constructor and other code...      public enum Status {         @SerializedName("0")         BUY,         @SerializedName("1")         DOWNLOAD,         @SerializedName("2")         DOWNLOADING,         @SerializedName("3")         OPEN      } } 

in the json file you have just a field "status": "N",, where N=0,1,2,3 - depend on the Status values. So that's all, GSON works fine with the values for the nested enum class. In my case i've parsed a list of Items from json array:

List<Item> items = new Gson().<List<Item>>fromJson(json,                                           new TypeToken<List<Item>>(){}.getType());