Database Connection Singleton

Connection.java

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package org.secondstack.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 *
 * @author Deny Prasetyo
 * @modified by : Athul Muralidharan 
   (replaced postgres with  mysql )
 
 */
public class DatabaseConnection {

	private static DatabaseConnection instance;
	private Connection connection;
	private static DatabaseConnection instance;
	private Connection connection;
	private static final String DRIVER = "com.mysql.jdbc.Driver";

	private static final String USER = System.getenv("DB_USERNAME");
	private static final String PASSWORD = System.getenv("DB_PASSWORD");
	private static final String SCHEMA = System.getenv("DB_SCHEMA");
	private static final String DB_HOSTNAME = System.getenv("DB_HOSTNAME");

	private static final String URL = String.format("jdbc:mysql://%s/%s", DB_HOSTNAME, SCHEMA);


    private DatabaseConnection() throws SQLException {
        try {
            Class.forName(DRIVER);
            this.connection = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException ex) {
            System.out.println("Database Connection Creation Failed : " + ex.getMessage());
        }
    }

    public Connection getConnection() {
        return connection;
    }

    public static DatabaseConnection getInstance() throws SQLException {
        if (instance == null) {
            instance = new DatabaseConnection();
        } else if (instance.getConnection().isClosed()) {
            instance = new DatabaseConnection();
        }

        return instance;
    }
}