com.javacreed.examples.app.DbHelper.java Source code

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Here is the source code for com.javacreed.examples.app.DbHelper.java

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/**
 * Copyright 2012-2014 Java Creed.
 * 
 * Licensed under the Apache License, Version 2.0 (the "<em>License</em>");
 * 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.javacreed.examples.app;

import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.googlecode.flyway.core.Flyway;

public class DbHelper {

    private static final Logger LOGGER = LoggerFactory.getLogger(DbHelper.class);

    private static final DbHelper INSTANCE = new DbHelper();

    public static Connection getConnection() throws SQLException {
        return DbHelper.getInstance().getDataSource().getConnection();
    }

    public static DbHelper getInstance() {
        return DbHelper.INSTANCE;
    }

    private BasicDataSource ds;

    private DbHelper() {
    }

    public void close() {
        if (ds != null) {
            DbHelper.LOGGER.debug("Closing the data source");
            try {
                ds.close();
            } catch (final SQLException e) {
                DbHelper.LOGGER.error("Failed to close the data source", e);
            }
        }
    }

    public DataSource getDataSource() {
        return ds;
    }

    public void init() {
        DbHelper.LOGGER.debug("Loading properties");
        final Properties properties = new Properties();
        properties.put("db.path", "target/db");
        properties.put("db.username", "sa");
        properties.put("db.password", "");
        try {
            properties.load(getClass().getResourceAsStream("/app.properties"));
        } catch (final IOException e) {
            DbHelper.LOGGER.error("Failed to load the properties");
        }

        DbHelper.LOGGER.debug("Creating the data source");
        ds = new BasicDataSource();
        ds.setDriverClassName("org.h2.Driver");
        ds.setUrl("jdbc:h2:" + properties.getProperty("db.path"));
        ds.setUsername(properties.getProperty("db.username"));
        ds.setPassword(properties.getProperty("db.password"));

        DbHelper.LOGGER.debug("Executing Flyway (database migration)");
        final Flyway flyway = new Flyway();
        flyway.setDataSource(ds);
        flyway.migrate();
    }

    public void registerShutdownHook() {
        Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
            @Override
            public void run() {
                close();
            }
        }));
    }

}