jive中DbUser和DbUserManager的设计问题

03-03-13 hcxjdon

时间所限，只研究了User, UserManager, DbUser, DbUserManager几个类。DbUserManager管理DbUser,删除的时候用自己的function DeleteUser,但是创建新User的时候要调用DbUser的insertIntoDb.如此设计似乎权责不明，欠妥。DbUser应与数据库中每条记录对应，相关的CRUD操作完全交由DbUserManager完成，这样也便于以后做DAO。各位以为如何？

EricZheng

2003-03-14 09:14

DbUserManager is responsible for creating or remove the DbUser object from memory.
So on Manager layer,it is just DbUserManager to focus on creating or destroying the DbUser object(creatUser()&deleteUser())
On Database layer,it is just DbUser to operate on database.

hcxjdon

2003-03-14 10:03

DbUserManager.deleteUser直接对数据库操作了。再看看源代码。

EricZheng

2003-03-14 14:11

I'm sorry.Now i can't input the chinese.
Yes,you are right.In DbUserManager deleteUser(),it directly operate on the database.It is not a good design.
Suggest to move deleteUser() to DbUser class.
Before this DbUser object was remove from Cache,this method should be invoked.

hcxjdon

2003-03-14 16:59

DbUserManger.users仍有数据库操作。
我的建议是将数据库操作全部移至DbUserManager中，这样方便封装数据库操作，做DAO，方便数据库移植。否则DbUser,DbUserManager都要做DAO,太麻烦。

EricZheng

2003-03-14 17:31

No,i don't think so.
If use DAO, SQL language can't coded in both DbUserManager and DbUser. DbUserManager's design uses FACADE design pattern.Client class just uses DbUserManager's method to do common things and need not care detail implementation in DbUser class.There will also be a class named "DAOFactory" to create a suite of DAO objects named "SQLServerDAO" or "OracleDAO" .etc

hcxjdon

2003-03-15 09:35

我感觉并非如此
UserManager可以看作facade, DbUserManager是implementation.
事实上DbUserManager.users/users(...)都有直接数据库操作

或者我对facade模式有误解？

EricZheng

2003-03-17 09:49

"manager" means some detail implement will be hidden.That's why most 'manager' class uses FACADE pattern.