DbManager.java

package repository;

/**
 * @author Xuesong Meng&Yidu Liang
 * @author Joanne Zhuo
 */
import java.io.File;
import java.io.FileReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class DbManager {

	/**
	 * Hard-coded database access information
	 */
	private static final String SERVER = "localhost:3306";
	private static final String USER = "root";
	// Modified by Xuesong Meng, No password.
	//private static final String PASSWORD = "12345";
	private static final String PASSWORD = "1234";
	private static final String DATABASE = "clubuml";
	// as long as you're using mysql, leave this alone.
	private static final String DATABASE_TYPE = "mysql";

	/* ------------- SQL Variables ------------- */
	/**
	 * The SQL connection to the database
	 */
	static Connection con;

	/**
	 * Gets a connection to for the manager and makes a good effort to make sure
	 * it is open
	 * 
	 * @return either an open connection or null
	 */
	public static synchronized Connection getConnection() {
		try {
			if (con != null && con.isClosed()) {
				con = null;
			}
		} catch (SQLException e) {
			con = null;
		}
		connect();
		return con;
	}

	/**
	 * Closes the database connection
	 */
	public static void disconnect() {
		if (con == null) {
			return;
		}

		try {
			con.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}

		con = null;
	}

	/**
	 * Utility method to validate connection is valid.
	 * 
	 * @return true if DATABASE is available; false otherwise.
	 */
	public static boolean isConnected() {
		if (con == null) {
			return false;
		}

		try {
			return !con.isClosed();
		} catch (SQLException e) {
			e.printStackTrace();

			return false;
		}
	}

	/**
	 * Establish a connection
	 * 
	 * @return true if success; false if fail
	 */
	public static boolean connect() {
		// already connected.
		if (con != null) {
			return true;
		}

		// Register the JDBC driver for MySQL. Simply accessing the class
		// will properly initialize everything.
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException cnfe) {
			System.err.println("Unable to locate mySQL drivers");
			return false;
		}

		try {

			// Get a connection to the database for a
			// user with the given user name and password.
			if (System.getProperty("os.name").equals("Linux") && System.getProperty("user.name").equals("tomcat7")) {
				// Connection for rho (need to move this to a file. outside of webapps folder for security)
				// Modified by Xuesong Meng
				//con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/ClubUML","csye7945", "north7945");
				con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/clubuml","localhost", "");
			} else {
				String url = "jdbc:" + DATABASE_TYPE + "://" + SERVER + "/" + DATABASE;
				con = DriverManager.getConnection(url, USER, PASSWORD);				
			}
			
			return true;
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
	}
}