Java设计模式(8) —— 抽象工厂

Abstract Factory

 

英文简单描述

Intent
Provide an interface for creating families of related or dependent objects without specifying their concrete classes.

How to
AbstractFactory
declares an interface for operations that create abstract product objects.

ConcreteFactory
implements the operations to create concrete product objects.

AbstractProduct
declares an interface for a type of product object.

ConcreteProduct
defines a product object to be created by the corresponding concrete factory.
implements the AbstractProduct interface.

Client
uses only interfaces declared by AbstractFactory and AbstractProduct classes.

Known cases

Look and Feel

Persistance Tier

 

UML

 

此模式经常与工厂模式和单例模式一同使用

 

代码：

public class DAOFactoryCreator {public static int ORACLE_DAOFACTORY = 0;public static int MYSQL_DAOFACTORY = 0;private static DAOFactoryCreator unique = new DAOFactoryCreator();private DAOFactoryCreator() {}public static DAOFactoryCreator getInstance() {return unique;}public IDAOFactory getDAOFactory(int type) {IDAOFactory factory = null;switch (type) {case 0:factory = OracleDAOFactory.getInstance();break;case 1:factory = MysqlDAOFactory.getInstance();break;default:throw new RuntimeException("Unsupported dao factory type exception");}return factory;}}public interface IDAOFactory {IUserDAO createUserDAO();ISystemDAO createSystemDAO();}public class OracleDAOFactory implements IDAOFactory {private static OracleDAOFactory factory = new OracleDAOFactory();private OracleDAOFactory() {}public static OracleDAOFactory getInstance() {return factory;}public ISystemDAO createSystemDAO() {return new OracleSystemDAO();}public IUserDAO createUserDAO() {return new OracleUserDAO();}}public class MysqlDAOFactory implements IDAOFactory {private static MysqlDAOFactory factory = new MysqlDAOFactory();private MysqlDAOFactory() {}public static MysqlDAOFactory getInstance() {return factory;}public ISystemDAO createSystemDAO() {return new MysqlSystemDAO();}public IUserDAO createUserDAO() {return new MysqlUserDAO();}}public interface IUserDAO {void insert();}public interface ISystemDAO {List query();}public class OracleUserDAO implements IUserDAO {public void insert() {// todo}}public class OracleSystemDAO implements ISystemDAO {public List query() {// todoreturn null;}}public class MysqlUserDAO implements IUserDAO {public void insert() {// todo}}public class MysqlSystemDAO implements ISystemDAO {public List query() {// todoreturn null;}}