Example  9.1 Abstract DAOFactory Class

// Abstract class DAO Factory
public abstract class DAOFactory {

  // List of DAO types supported by the factory
  public static final int CLOUDSCAPE = 1;
  public static final int ORACLE = 2;
  public static final int SYBASE = 3;
  ...

  // There will be a method for each DAO that can be 
  // created. The concrete factories will have to 
  // implement these methods.
  public abstract CustomerDAO getCustomerDAO();
  public abstract AccountDAO getAccountDAO();
  public abstract OrderDAO getOrderDAO();
  ...

  public static DAOFactory getDAOFactory(
      int whichFactory) {
  
    switch (whichFactory) {
      case CLOUDSCAPE: 
          return new CloudscapeDAOFactory();
      case ORACLE    : 
          return new OracleDAOFactory();      
      case SYBASE    : 
          return new SybaseDAOFactory();
      ...
      default           : 
          return null;
    }
  }
}