com.impetus.kvapps.runner.AppRunner.java Source code

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Here is the source code for com.impetus.kvapps.runner.AppRunner.java

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/*******************************************************************************
 * * Copyright 2013 Impetus Infotech.
 *  *
 *  * Licensed under the Apache License, Version 2.0 (the "License");
 *  * you may not use this file except in compliance with the License.
 *  * You may obtain a copy of the License at
 *  *
 *  *      http://www.apache.org/licenses/LICENSE-2.0
 *  *
 *  * Unless required by applicable law or agreed to in writing, software
 *  * distributed under the License is distributed on an "AS IS" BASIS,
 *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  * See the License for the specific language governing permissions and
 *  * limitations under the License.
 ******************************************************************************/
package com.impetus.kvapps.runner;

import java.util.Iterator;
import java.util.List;
import java.util.Set;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.impetus.kvapps.entities.User;

/**
 * @author impetus
 * 
 * Sample Application runner. Application demonstrates:
 * <li> poly glot persistence, where user information {@link User} is getting persisted into mysql and corresponding tweets into Cassandra.</li>
 * <li> Fetch user(alongwith tweets) in polyglot way </li>
 * <li> Fetch tweets using native query support </li> 
 * <li> Since {kundera.ddl.auto.prepare} is set to "create"(Please refer src/main/resources/persistence.xml). 
 * hence schema will be automatically managed by Kundera itself.</li>
 * 
 * Also, application takes path to excel data file as an input arguments.
 */
public class AppRunner {

    /** the log used by this class. */
    private static Log logger = LogFactory.getLog(AppRunner.class);

    /**
     * main runner method
     * @param args takes excel data file as input argument args[0].
     */
    public static void main(String[] args) {

        // Override CQL version while instantiating entity manager factory.

        EntityManagerFactory emf = Persistence.createEntityManagerFactory("twissandra,twingo,twirdbms");
        EntityManager em = emf.createEntityManager();

        try {

            //populate user set from excel sheet.
            Set<User> users = UserBroker.brokeUserList(args[0]);

            for (Iterator<User> iterator = users.iterator(); iterator.hasNext();) {
                User user = (User) iterator.next();

                // on Persist
                ExecutorService.onPersist(em, user);

                // on find by id.
                ExecutorService.findByKey(em, "BigDataUser");

                List<User> fetchedUsers = ExecutorService.onQueryByEmail(em, user);

                if (fetchedUsers != null && fetchedUsers.size() > 0) {
                    logger.info(user.toString());
                }

                logger.info("");
                System.out.println("#######################Querying##########################################");
                logger.info("");
                logger.info("");

            }

            // Execute wild search query.
            String query = "Select u from User u";
            logger.info(query);
            ExecutorService.findByQuery(em, query);

            // // Execute native CQL. Fetch tweets for given user.
            logger.info("");
            System.out.println("#######################Querying##########################################");
            logger.info("");
            logger.info("");

            query = "Select * from tweets where user_id='RDBMSUser'";
            logger.info(query);
            ExecutorService.findByNativeQuery(em, query);
        } finally {
            onDestroyDBResources(emf, em);
        }
    }

    /**
     * After successful processing close entity manager and it's factory instance.
     * 
     * @param emf          entity manager factory instance.
     * @param em           entity manager instance
     */
    private static void onDestroyDBResources(EntityManagerFactory emf, EntityManager em) {
        if (emf != null) {
            emf.close();
        }

        if (em != null) {
            em.close();
        }
    }

}