daofactory.java

学生成绩管理系统

package com.stuman.util;

import com.stuman.dao.AdminDAO;
import com.stuman.dao.ClassesDAO;
import com.stuman.dao.CourseDAO;
import com.stuman.dao.EnrolDAO;
import com.stuman.dao.StudentDAO;
import com.stuman.dao.TeacherDAO;

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

	private static String className = "com.stuman.dao.imp.HibernateDAOFactory";

	private static DAOFactory factory = null;

	public static DAOFactory getInstance() {
		if (factory == null) {
			synchronized (initLock) {
				if (factory == null) {
					// Note, the software license expressely forbids
					// tampering with this check.
					// LicenseManager.validateLicense("Jive Forums Basic",
					// "2.0");

					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();
	
	static {
		try {
			Class c = Class.forName(className);
			factory = (DAOFactory) c.newInstance();
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InstantiationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}