GsonJsonRpcComposer.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.api.core.jsonrpc.impl;

import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.inject.Singleton;

import org.eclipse.che.api.core.jsonrpc.commons.JsonRpcComposer;
import org.eclipse.che.api.core.jsonrpc.commons.JsonRpcParams;
import org.eclipse.che.api.core.jsonrpc.commons.JsonRpcResult;
import org.eclipse.che.dto.server.DtoFactory;

import java.util.List;

import static java.util.Collections.emptyList;
import static org.eclipse.che.api.core.jsonrpc.commons.JsonRpcUtils.cast;

@Singleton
public class GsonJsonRpcComposer implements JsonRpcComposer {
    @Override
    public <T> T composeOne(JsonRpcParams params, Class<T> type) {
        return composeOne(type, params.getOne());
    }

    @Override
    public <T> List<T> composeMany(JsonRpcParams params, Class<T> type) {
        return composeMany(type, params.getMany());
    }

    @Override
    public <T> T composeOne(JsonRpcResult result, Class<T> type) {
        return composeOne(type, result.getOne());
    }

    @Override
    public <T> List<T> composeMany(JsonRpcResult result, Class<T> type) {
        return composeMany(type, result.getMany());
    }

    private <T> T composeOne(Class<T> type, Object paramObject) {
        if (paramObject instanceof JsonElement) {
            JsonElement jsonElement = (JsonElement)paramObject;
            return DtoFactory.getInstance().createDtoFromJson(jsonElement.toString(), type);
        }

        return cast(paramObject);
    }

    private <T> List<T> composeMany(Class<T> type, List<?> paramsList) {
        if (paramsList.isEmpty()){
            return emptyList();
        }

        if (paramsList.get(0) instanceof JsonElement) {
            JsonArray jsonArray = new JsonArray();
            for (int i = 0; i < paramsList.size(); i++) {
                JsonElement jsonElement = (JsonElement)paramsList.get(i);
                jsonArray.set(i, jsonElement);
            }
            return DtoFactory.getInstance().createListDtoFromJson(jsonArray.toString(), type);
        }

        return cast(paramsList);
    }
}