Question

i am using mongodb as cloud server for my android app.Mongodb java library doesn’t work in Android so i am using rest api .i wrote the following code to get the json response and cast them into MyClass but its giving IllegalStateException with

    java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_Object at line 1 column 35

Code :

              try {  HttpGet mRequest = new HttpGet("https://api.mongolab.com/api/1/databases/mydb/collections/mycol?apiKey=myKey");    

                     DefaultHttpClient client = new DefaultHttpClient();
   try {
              HttpResponse response = client.execute(mRequest);

              InputStream source = response.getEntity().getContent();

              Reader reader = new InputStreamReader(source);

              Gson gson = new Gson();

          Type typeOfCollectionOfMyObject = new TypeToken<Collection<MYObject>>(){}.getType();

          quizDBObjectList = gson.fromJson(reader, typeOfCollectionOfMyObject);

          } catch (IOException e) {
          mRequest.abort();
          }

this is not the whole code but i am getting the exception in this block.Any Help ?

Definition of MYObject is

           public class MYObject { 

                   private long index ;
                   private String question;
                   private String answer;
                   private String optionA;
                   private String optionB;
                   private String optionC;
                   private String optionD;
                   private String createdAt;
                   private String active;
                //getters and setters of data members
      }

and the response i got was :

                           [ { "_id" : { "$oid" : "505ab996aded66f4c1ccc7f2"} , "index" : 0 , "question" : "some text ?" , "optiona" : "optionA" , "optionb" : "optionB" , "optionc" : "OptionC" , "optiond" : "optionD" , "answer" : "answer" , "created_at" : { "$date" : "2012-09-20T06:37:04.306Z"} , "Active" : "1"} , { "_id" : { "$oid" : "505ab997aded66f4c1ccc7f3"} , "index" : 1 , ..../objects like that]

clearly i was not aware of the fact that the _id would be responded by the server.
Can you give me the correct class definition to cast this json object into my customized class. thanks

Answer 1

java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_Object at line 1 column 35

This says it all, there should be somewhere [ instead of {. Maybe you get a single object instead of an array?

The above might help or not. In order to get a better answer the following is needed:

• definition of MYObject
• the exact parsed String

You can get the parsed String e.g. by reading from reader into a StringBuider or simpler by using Guava’s CharStreams.toString(reader).