/*
 * Copyright (c) 2009 Lockheed Martin Corporation
 *
 * 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 org.eurekastreams.testing;

import java.sql.Connection;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.dbunit.database.DatabaseConnection;
import org.dbunit.database.IDatabaseConnection;
import org.dbunit.dataset.IDataSet;
import org.dbunit.dataset.xml.FlatXmlDataSet;
import org.dbunit.operation.DatabaseOperation;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.datasource.DataSourceUtils;

//TODO must be brought out into the feed reader project. 

/**
 * Helper class for loading DBUnit datasource xml files embedded in the project
 * as resources.
 * 
 * The main function of this class is to make it easier to set up the data
 * mappers.
 * 
 * Note: This is very specific to our configuration - it's loading all Spring
 * files found in "classpath:applicationContext*-test.xml", and looking for the
 * bean named "dataSource". This is no more hard-coded than annotations in our
 * tests, and does make our setUp methods much easier to manage.
 */
public final class FeedReaderDBUnitFixtureSetup
{    
    /** logger instance. */
    private static Log logger = LogFactory.getLog(FeedReaderDBUnitFixtureSetup.class);

    /**
     * Locations of the application context files to load for finding the data
     * source.
     */
    private static final String[] APPLICATION_CONTEXT_LOCATIONS = { "classpath:feedReaderContext*-test.xml" };

    /**
     * Name of the data source bean in the Spring config.
     */
    private static final String DATA_SOURCE_BEAN_NAME = "dataSource";
    
    /**
     * Private default constructor. Utility classes should not have public 
     * default constructor.
     */
    private FeedReaderDBUnitFixtureSetup()
    {
        //no-op
    }

    /**
     * Load up the XML dataset found at the input file path, using the data
     * source found in the bean "dataSource" in Spring files found in
     * "classpath:applicationContext*-test.xml".
     * 
     * @param newDatasetPath
     *            The resource path of the dataset xml file - for example:
     *            "/dataset.xml"
     * @throws Exception
     *             on any errors
     */
    public static void loadDataSet(final String newDatasetPath) throws Exception
    {
        // Get the Spring application context
        ApplicationContext appContext = new ClassPathXmlApplicationContext(
                APPLICATION_CONTEXT_LOCATIONS);

        // Get the data source from Spring
        DataSource dataSource = (DataSource) appContext
                .getBean(DATA_SOURCE_BEAN_NAME);

        logger.info("About to load up the test dataset at path '"
                + newDatasetPath + "'");

        // Get the connection to the database
        Connection connection = DataSourceUtils.getConnection(dataSource);
        IDatabaseConnection dbUnitCon = new DatabaseConnection(connection);

        // Get the data from the file at the input resource path
        IDataSet dataSet = new FlatXmlDataSet(FeedReaderDBUnitFixtureSetup.class
                .getResourceAsStream(newDatasetPath));

        // insert the data set into the database with a clean insert
        try
        {
            DatabaseOperation.CLEAN_INSERT.execute(dbUnitCon, dataSet);
        } 
        finally
        {
            DataSourceUtils.releaseConnection(connection, dataSource);
        }
    }
}