daofactory.java

学校的课程管理及选课系统

package org.wangsong.dao;

public abstract class DAOFactory
{
	private static Object initLock = new Object();

	private static String className = "org.wangsong.dao.imp.HibernateDAOFactory";

	private static DAOFactory factory = null;

	public static DAOFactory getInstance()
	{
		if (factory == null)
		{
			synchronized (initLock)
			{
				if (factory == null)
				{

					String classNameProp = DAOConfig
							.getProperty("DAOFactory.className");
					if (classNameProp != null)
					{
						className = classNameProp;
					}
					try
					{
						// Load the class and create an instance.
						Class c = Class.forName(className);
						factory = (DAOFactory) c.newInstance();
					}
					catch (Exception e)
					{
						System.err.println("Failed to load DAOFactory class "
								+ className
								+ ". StuMan cannot function normally.");
						e.printStackTrace();
						return null;
					}
				}
			}

		}
		return factory;
	}

	public abstract StudentDAO createStudentDAO();

	public abstract TeacherDAO createTeacherDAO();

	public abstract AdminDAO createAdminDAO();

	public abstract CourseDAO createCourseDAO();

	public abstract ClassesDAO createClassesDAO();

	public abstract EnrolDAO createEnrolDAO();  

}