com.kurento.kmf.jsonrpcconnector.internal.message.MessageUtils.java Source code

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Here is the source code for com.kurento.kmf.jsonrpcconnector.internal.message.MessageUtils.java

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/*
 * (C) Copyright 2013 Kurento (http://kurento.org/)
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Lesser General Public License
 * (LGPL) version 2.1 which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/lgpl-2.1.html
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 */
package com.kurento.kmf.jsonrpcconnector.internal.message;

import static com.kurento.kmf.jsonrpcconnector.JsonUtils.getGson;

import java.util.Map.Entry;
import java.util.Set;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

public class MessageUtils {

    private static Logger log = LoggerFactory.getLogger(MessageUtils.class);

    public static <R> Response<R> convertResponse(Response<JsonElement> response, Class<R> resultClass) {

        R resultR = convertJsonTo(response.getResult(), resultClass);

        @SuppressWarnings("unchecked")
        Response<R> responseR = (Response<R>) response;

        responseR.setResult(resultR);

        return responseR;
    }

    public static <P> Request<P> convertRequest(Request<JsonElement> request, Class<P> paramsClass) {

        P paramsP = convertJsonTo(request.getParams(), paramsClass);

        @SuppressWarnings("unchecked")
        Request<P> requestP = (Request<P>) request;

        requestP.setParams(paramsP);

        return requestP;
    }

    private static <R> R convertJsonTo(JsonElement resultJsonObject, Class<R> resultClass) {

        if (resultJsonObject == null) {
            return null;
        }

        R resultR = null;
        if (resultClass == String.class || resultClass == Boolean.class || resultClass == Character.class
                || Number.class.isAssignableFrom(resultClass) || resultClass.isPrimitive()) {

            JsonElement value;
            if (resultJsonObject.isJsonObject()) {

                Set<Entry<String, JsonElement>> properties = ((JsonObject) resultJsonObject).entrySet();

                if (properties.size() > 1) {

                    Entry<String, JsonElement> prop = properties.iterator().next();

                    log.warn(
                            "Converting a result with {} properties in a value"
                                    + " of type {}. Selecting propoerty '{}'",
                            properties.size(), resultClass, prop.getKey());

                    value = prop.getValue();

                } else if (properties.size() == 1) {
                    value = properties.iterator().next().getValue();
                } else {
                    value = null;
                }

            } else if (resultJsonObject.isJsonArray()) {
                JsonArray array = (JsonArray) resultJsonObject;
                if (array.size() > 1) {
                    log.warn("Converting an array with elements in a value " + "of type. Selecting first element",
                            array.size(), resultClass);

                }

                value = array.get(0);
            } else {
                value = resultJsonObject;
            }

            resultR = getGson().fromJson(value, resultClass);
        } else {
            resultR = getGson().fromJson(resultJsonObject, resultClass);
        }
        return resultR;
    }

}