Java tutorial
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package com.shampan.db.codec; import com.fasterxml.jackson.databind.ObjectMapper; import com.mongodb.MongoClient; import com.shampan.db.collections.MessageDetailsDAO; import java.util.UUID; import org.bson.BsonReader; import org.bson.BsonString; import org.bson.BsonValue; import org.bson.BsonWriter; import org.bson.Document; import org.bson.codecs.Codec; import org.bson.codecs.CollectibleCodec; import org.bson.codecs.DecoderContext; import org.bson.codecs.EncoderContext; /** * * @author Sampan IT */ public class MessageDetailsCodec implements CollectibleCodec<MessageDetailsDAO> { private Codec<Document> documentCodec; public MessageDetailsCodec() { this.documentCodec = MongoClient.getDefaultCodecRegistry().get(Document.class); } @Override public MessageDetailsDAO decode(BsonReader reader, DecoderContext decoderContext) { Document document = documentCodec.decode(reader, decoderContext); ObjectMapper mapper = new ObjectMapper(); MessageDetailsDAO messageDetails = new MessageDetailsDAO(); try { messageDetails = mapper.readValue(document.toJson().toString(), MessageDetailsDAO.class); } catch (Exception ex) { ex.printStackTrace(); } return messageDetails; } @Override public void encode(BsonWriter writer, MessageDetailsDAO messageDetails, EncoderContext encoderContext) { ObjectMapper mapper = new ObjectMapper(); String json = ""; try { json = mapper.writeValueAsString(messageDetails); } catch (Exception ex) { ex.printStackTrace(); } Document doc = new Document(); documentCodec.encode(writer, Document.parse(json), encoderContext); } @Override public Class<MessageDetailsDAO> getEncoderClass() { return MessageDetailsDAO.class; } @Override public MessageDetailsDAO generateIdIfAbsentFromDocument(MessageDetailsDAO messageDetails) { if (!documentHasId(messageDetails)) { messageDetails.set_id(UUID.randomUUID().toString()); } return messageDetails; } @Override public boolean documentHasId(MessageDetailsDAO messageDetails) { return messageDetails.get_id() != null; } @Override public BsonValue getDocumentId(MessageDetailsDAO messageDetails) { if (!documentHasId(messageDetails)) { throw new IllegalStateException("The document does not contain an _id"); } return new BsonString((String) messageDetails.get_id()); } }