uk.ac.sheffield.vtts.client.pojo

Class Login

java.lang.Object

uk.ac.sheffield.vtts.client.pojo.Login

public class Login
extends java.lang.Object

Login is a correct POJO implementation of the Login.xml specification. This uses the State Pattern (a Design Pattern from Gamma, et al.) for its implementation. All requests are delegated to an abstract State, which has concrete subclasses LoggedOut and LoggedIn, which respond to certain requests and ignore others. This is a good implementation strategy to ensure that no information is returned by a service, when it is in an inappropriate state.

Otherwise, a Map is used to represent the table of known users and passwords; one of these corresponds to the valid test user from the Login.xml specification. This simple example performs no other actions apart from controlling the logged state of the user.

Suggestions are given for how to modify the source code to seed faults deliberately, which will be detected during testing.

Version:

1.0

Author:

Anthony J H Simons

Constructor Summary

Constructors

Constructor and Description
Login() Creates this Login service.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.String	getScenario() Returns the last scenario that was enacted.
java.lang.String	getState() Returns the last state that was entered.
void	login(java.lang.String username, java.lang.String password) Attempts to log a user into the system.
void	logout() Attempts to log a user out of the system.
void	timeout() Attempts to time a user out of the system.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Login

public Login()

Creates this Login service. Enacts the scenario create/ok. Creates a table of valid users with their passwords, and then enters the LoggedOut state. For POJO implementations, the constructor is also used to reset the service.

Method Detail

getScenario

public java.lang.String getScenario()

Returns the last scenario that was enacted. This implementation logs separately the request received and the response that was triggered (which is state-dependent). The name of the last scenario that was enacted is obtained by concatenating the request, "/" and the response.

Returns:

the last scenario that was enacted.

getState

public java.lang.String getState()

Returns the last state that was entered. This implementation models the states explicitly as nested inner classes, which also have access to the Account's fields. The name of the current state is obtained by reflection on the class name.

Returns:

the name of the current State instance.

login

public void login(java.lang.String username,
         java.lang.String password)

Attempts to log a user into the system. If the state is already LoggedIn, enacts the scenario login/ignore. If the state is LoggedOut, checks whether the user and corresponding password are correct. If so, enacts the scenario login/ok and changes the state to LoggedIn. Otherwise enacts the scenario login/error and leaves the state unchanged as LoggedOut.

Parameters:

username - the user name.

password - the password.

logout

public void logout()

Attempts to log a user out of the system. If the state is already LoggedOut, enacts the scenario logout/ignore and leaves the state unchanged. Otherwise, enacts the scenario logout/ok and changes the state to LoggedOut.

timeout

public void timeout()

Attempts to time a user out of the system. If the state is already LoggedOut, enacts the scenario timeout/ignore and leaves the state unchanged. Otherwise, enacts the scenario timeout/ok and changes the state to LoggedOut.