Spring Data Mongodb: json string to BasicDBObject - spring

Question

I've created this custom converter:
#Component
#WritingConverter
public class MetadataWriterConverter implements Converter<Metadata, DBObject> {
#Override
public DBObject convert(Metadata metadata) {
DBObject dbObject = new BasicDBObject();
dbObject.put("name", metadata.getName());
dbObject.put("metadata", (BasicDBObject) BasicDBObject.parse(reference.getMetadata()));
dbObject.removeField("_class");
return dbObject;
}
}
I'm getting this exception:
Caused by: org.bson.BsonInvalidOperationException: readStartDocument can only be called when CurrentBSONType is DOCUMENT, not when CurrentBSONType is ARRAY.
The problem is on:
(BasicDBObject) BasicDBObject.parse(metadata.getMetadata())
the content of metadata.getMetadata is: "[{'departament': 'JUST'}]".
Metadata class is:
public class Metadata {
private String id;
private String user;
private String metadata;
}
The content of metadata field is a json string, I'm trying to convert to BasicDbObject, but the problem appears when this string is an json array: [{},{}].
Guess:
Metadata met = new Metadata();
met.setId("Mdt1");
met.setUser("user");
met.setMetadata("[{'departament': 'JUST'}]");
What I want to get is:
{
"id": Mdt1,
"user": "user",
"metadata": [{"departament": "JUST"}]
}
Any ideas about how to refactor my converter?

Answer 1

Actually, BasicDBObject.parse() expects a JSONObject instead of a JSONArray that you are passing in your example. Check the docs here - http://api.mongodb.com/java/current/com/mongodb/BasicDBObject.html#parse-java.lang.String-
Instead, you can try converting your reference.getMetadata() into a valid JSON String and then using BasicDBList for your JSONArray. Something like below:
#Component
#WritingConverter
public class MetadataWriterConverter implements Converter<Metadata, DBObject>
{
#Override
public DBObject convert(Metadata metadata) {
DBObject dbObject = new BasicDBObject();
dbObject.put("name", metadata.getName());
String jsonString = String.format("{\"data\": " + reference.getMetadata() + "}");
BasicDBObject basicDBObject = (BasicDBObject) BasicDBObject.parse(jsonString);
BasicDBList parsedList = (BasicDBList) basicDBObject.get("data");
dbObject.put("metadata", parsedList);
dbObject.removeField("_class");
return dbObject;
}
}