ex8_3.txt

来自「j2ee core design patterns」· 文本 代码 · 共 32 行

Example 8.3 	OracleDAOFactory.java: Data Access Object Strategy Using Factory Method [GoF]
package com.corej2eepatterns.dao;

// imports
public class OracleDAOFactory extends DAOFactory {

	// package level constant used look up the 
	// DataSource name using JNDI
	static String DATASOURCE_DB_NAME =
			"java:comp/env/jdbc/CJPOraDB";

	public static CustomerDAO getCustomerDAO() 
			throws DAOException {
		return (CustomerDAO) createDAO(CustomerDAO.class);
	}

	public static EmployeeDAO getEmployeeDAO() 
			throws DAOException {
		return (EmployeeDAO) createDAO(EmployeeDAO.class);
	}

	// create other DAO instances
	. . .

	// method to create a DAO instance. Can be optimized to 
	// cache the DAO Class instead of creating it everytime.
	private Object createDAO(Class classObj) 
			throws DAOException {
		// create a new DAO using classObj.newInstance() or 
		// obtain it from a cache and return the DAO instance
	}
}