org.apache.struts.webapp.example
Interface UserDatabase

All Known Implementing Classes:

MemoryUserDatabase

public interface UserDatabase

A Data Access Object (DAO) interface describing the available operations for retrieving and storing Users (and their associated Subscriptions) in some persistence layer whose characteristics are not specified here. One or more implementations will be created to perform the actual I/O that is required.

Since:

Struts 1.1

Version:

$Rev: 471754 $ $Date: 2006-11-06 08:55:09 -0600 (Mon, 06 Nov 2006) $

Author:

Craig R. McClanahan

Method Summary

void	close() Finalize access to the underlying persistence layer.
User	createUser(String username) Create and return a new User defined in this user database.
User	findUser(String username) Return the existing User with the specified username, if any; otherwise return null.
User[]	findUsers() Return the set of Users defined in this user database.
void	open() Initiate access to the underlying persistence layer.
void	removeUser(User user) Remove the specified User from this database.
void	save() Save any pending changes to the underlying persistence layer.

Method Detail

createUser

User createUser(String username)

Create and return a new User defined in this user database.

Parameters:

username - Username of the new user

Throws:

IllegalArgumentExceptionif - the specified username is not unique

close

void close()
           throws Exception

Finalize access to the underlying persistence layer.

Throws:

Exception - if a database access error occurs

findUser

User findUser(String username)

Return the existing User with the specified username, if any; otherwise return null.

Parameters:

username - Username of the user to retrieve

findUsers

User[] findUsers()

Return the set of Users defined in this user database.

open

void open()
          throws Exception

Initiate access to the underlying persistence layer.

Throws:

Exception - if a database access error occurs

removeUser

void removeUser(User user)

Remove the specified User from this database.

Parameters:

user - User to be removed

Throws:

IllegalArgumentException - if the specified user is not associated with this database

save

void save()
          throws Exception

Save any pending changes to the underlying persistence layer.

Throws:

Exception - if a database access error occurs