source: trunk/src/main/java/omq/common/util/Serializers/GsonImp.java

package omq.common.util.Serializers;

import java.util.List;

import omq.common.message.Request;
import omq.common.message.Response;
import omq.exception.OmqException;
import omq.exception.SerializerException;
import omq.server.RemoteObject;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

/**
 * Json serialize implementation. It uses the Gson libraries.
 * 
 * @author Sergi Toda <sergi.toda@estudiants.urv.cat>
 * 
 */
public class GsonImp implements ISerializer {
        private final Gson gson = new Gson();

        @Override
        public byte[] serialize(Object obj) throws SerializerException {
                String json = gson.toJson(obj);
                return json.getBytes();
        }

        @Override
        public Request deserializeRequest(byte[] bytes, RemoteObject obj) throws SerializerException {
                String json = new String(bytes);

                JsonParser parser = new JsonParser();
                JsonObject jsonObj = parser.parse(json).getAsJsonObject();

                String id = jsonObj.get("id").getAsString();
                String method = jsonObj.get("method").getAsString();
                boolean async = jsonObj.get("async").getAsBoolean();

                List<Class<?>> types = obj.getParams(method);

                try {
                        JsonArray jsonArgs = (JsonArray) jsonObj.get("params");

                        // TODO: if (jsonArgs.size() == types.size())
                        int length = jsonArgs.size();
                        Object[] arguments = new Object[length];

                        int i = 0;
                        for (JsonElement element : jsonArgs) {
                                arguments[i] = gson.fromJson(element, types.get(i));
                                i++;
                        }
                        return new Request(id, method, async, arguments);
                } catch (NullPointerException e) {
                        return new Request(id, method, async, null);
                }
        }

        @Override
        public Response deserializeResponse(byte[] bytes, Class<?> type) throws SerializerException {
                String json = new String(bytes);

                JsonParser parser = new JsonParser();
                JsonObject jsonObj = parser.parse(json).getAsJsonObject();

                String id = jsonObj.get("id").getAsString();
                String idOmq = jsonObj.get("idOmq").getAsString();

                JsonElement jsonElement = jsonObj.get("result");
                Object result = gson.fromJson(jsonElement, type);

                JsonElement jsonError = jsonObj.get("error");
                OmqException error = gson.fromJson(jsonError, OmqException.class);

                return new Response(id, idOmq, result, error);
        }

}