import java.sql.*;
import java.util.*;

/**
 * A very, very simple connection pooling class for providing
 * clients with a connection to the database.
 * Clients call getConnection() and it tries to give the client
 * an existing connection, or creates one if one does not already
 * exist.
 */ 

public class DatabaseHook {

    /* Large database connection and driver info. */
    private static String DEFAULT_USER = "[username omitted]";
    private static String DEFAULT_PASS = "[password omitted]";
    private static String DEFAULT_URL  = "[url omitted]";
    private static String JDBC_DRIVER  = "org.gjt.mm.mysql.Driver";

    private static ArrayList connections = new ArrayList();
    private static Integer id = new Integer(1);

    public static ConnectionWrapper getConnection() {
	ConnectionWrapper conn = getConnection(DEFAULT_URL,
					       DEFAULT_USER, 
					       DEFAULT_PASS);
	return conn;
    }


    public static synchronized ConnectionWrapper getConnection(String url, 
							       String user, 
							       String pass) {
	Iterator i = connections.iterator();
	ConnectionWrapper c;
	while (i.hasNext()) {
	    c = (ConnectionWrapper) i.next();
	    if (c.checkOut()) {
		return c;
	    }
	}

	c = openNewConnection(url, user, pass);
	c.checkOut();
	return c;
    }

    private static synchronized ConnectionWrapper openNewConnection(String url,
				  String user, String pass) {
	Connection con = null;
	ConnectionWrapper w;

	try {
	    Class.forName(JDBC_DRIVER);
	    con = DriverManager.getConnection(url, user, pass);
	    w = new ConnectionWrapper(con);
	    connections.add(w);
	} catch (Exception e) {
	    e.printStackTrace(System.err);
	    w = null;
	}
	return w;
    }
}