Package org.cis1200

Class ServerModel

java.lang.Object

org.cis1200.ServerModel

public final class ServerModel
extends Object

The ServerModel is the class responsible for tracking the state of the server, including its current users and the channels they are in. This class is used by subclasses of Command to: 1. handle commands from clients, to create channels, send messages, etc. and 2. handle commands from ServerBackend to coordinate client connection/disconnection.

Constructor Summary

Constructors

Constructor	Description
ServerModel()	Constructs a ServerModel.

Method Summary

Modifier and Type	Method	Description
ResponseSet	changeNickname(NicknameCommand nickCommand)	This method is called when a user wants to change their nickname.
ResponseSet	createChannel(CreateCommand createCommand)	This method is called when a user wants to create a channel.
ResponseSet	deregisterUser(int userId)	This method is automatically called when a client disconnects from the server.
boolean	existingNickname(String nickname)	Is this an existing nickname?
boolean	existingUserId(Integer userId)	Is this a userId that is known to the server?
Collection<String>	getChannels()	Gets a collection of the names of all the channels that are present on the server.
String	getNickname(int userId)	Gets the nickname currently associated with the given userId.
String	getOwner(String channelName)	Gets the nickname of the owner of the given channel.
Collection<String>	getRegisteredUsers()	Gets a collection of the nicknames of all users who are registered with the server.
int	getUserId(String userNickname)	Gets the userId currently associated with the given nickname.
Collection<Integer>	getUserIdsInChannel(String channelName)	Gets a collection of the userIds of all users who are in the channel.
SortedSet<String>	getUserNicknamesInChannel(String channelName)	Gets an alphabetically sorted set of the nicknames of all the users in a given channel.
ResponseSet	inviteUser(InviteCommand inviteCommand)	This method is called when a channel's owner adds a user to that channel.
static boolean	isValidName(String name)	Determines if a given name is valid or invalid (contains at least one alphanumeric character, and no non-alphanumeric characters).
ResponseSet	joinChannel(JoinCommand joinCommand)	This method is called when a user wants to join a channel.
ResponseSet	kickUser(KickCommand kickCommand)	This method is called when a channel's owner removes a user from that channel.
ResponseSet	leaveChannel(LeaveCommand leaveCommand)	This method is called when a user wants to leave a channel.
ResponseSet	registerUser(int userId)	This method is automatically called when a new client connects to the server.
ResponseSet	sendMessage(MessageCommand messageCommand)	This method is called when a user wants to send a message to a channel.

Methods inherited from class java.lang.Object

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

Constructor Details

ServerModel

public ServerModel()

Constructs a ServerModel. Make sure to initialize any collections used to model the server state here.

Method Details

existingNickname

public boolean existingNickname(String nickname)

Is this an existing nickname?

Parameters:

nickname - any string

Returns:

whether the nickname is currently in use by any user in any channel

existingUserId

public boolean existingUserId(Integer userId)

Is this a userId that is known to the server?

Parameters:

userId - any integer

Returns:

whether the userId has been registered for any client

getUserId

public int getUserId(String userNickname)

Gets the userId currently associated with the given nickname.

Parameters:

userNickname - The nickname for which to get the associated userId

Returns:

The userId of the user with the provided nickname if such a user exists

Throws:

IllegalArgumentException - if there is no userId associated with the nickname.

getNickname

public String getNickname(int userId)

Gets the nickname currently associated with the given userId.

Parameters:

userId - The userId for which to get the associated nickname

Returns:

The nickname of the user with that userId if such a user exists

Throws:

IllegalArgumentException - if the userId is not in use

getRegisteredUsers

public Collection<String> getRegisteredUsers()

Gets a collection of the nicknames of all users who are registered with the server. Modifications to the returned collection should not affect the server state. This method is provided for testing.

Returns:

The collection of registered user nicknames

getChannels

public Collection<String> getChannels()

Gets a collection of the names of all the channels that are present on the server. Modifications to the returned collection should not affect the server state. This method is public for testing.

Returns:

The collection of channel names

getUserIdsInChannel

public Collection<Integer> getUserIdsInChannel(String channelName)

Gets a collection of the userIds of all users who are in the channel. Modifications to the returned collection should not affect the server state. This method is public for testing.

Parameters:

channelName - The channel

Returns:

The collection of IDs

Throws:

IllegalArgumentException - if the channel does not exist

getUserNicknamesInChannel

public SortedSet<String> getUserNicknamesInChannel(String channelName)

Gets an alphabetically sorted set of the nicknames of all the users in a given channel. Modifications to the returned collection should not affect the server state. This method is public for testing.

Parameters:

channelName - The channel for which to get member nicknames

Returns:

A collection of all user nicknames in the channel

Throws:

IllegalArgumentException - if there is no channel with the given name

getOwner

public String getOwner(String channelName)

Gets the nickname of the owner of the given channel. This method is provided for testing.

Parameters:

channelName - The channel for which to get the owner nickname

Returns:

The nickname of the channel owner if such a channel exists

Throws:

IllegalArgumentException - if there is no channel with the given name

registerUser

public ResponseSet registerUser(int userId)

This method is automatically called when a new client connects to the server. It should generate a default nickname with generateUniqueNickname(), store the new userId and nickname in your ServerModel state. The method should return a single Response.connected(java.lang.Integer, java.lang.String) response to the client.

Parameters:

userId - The new user's unique identifier (created by the backend)

Returns:

A ResponseSet object indicating that the connection was successful.

deregisterUser

public ResponseSet deregisterUser(int userId)

This method is automatically called when a client disconnects from the server. This method should take the following actions, not necessarily in this order, and notify other users that the client has left. (1) The disconnected user's information should be deleted from the ServerModel's internal state (2) All channels owned by the disconnected user should be deleted the ServerModel's internal state

Parameters:

userId - The unique userId of the user to deregister

Returns:

a ResponseSet object containing Response.disconnected(java.lang.Integer, java.lang.String) responses addressed to all users who shared a channel with the disconnected user, excluding the disconnected user.

Throws:

IllegalArgumentException - if the userID is not currently registered. (If you correctly use previous methods you've written, this could happen automatically!)

changeNickname

public ResponseSet changeNickname(NicknameCommand nickCommand)

This method is called when a user wants to change their nickname.

Parameters:

nickCommand - The NicknameCommand object containing all information needed to attempt a nickname change

Returns:

If the nickname change is successful, a ResponseSet containing a Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) response for each user that shares at least one channel with the sender, including the sender. Each response should contain the original NicknameCommand, and the old nickname. If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.INVALID_NAME if the proposed nickname is not valid according to isValidName(String) (2) ErrorCode.NAME_ALREADY_IN_USE if there is already a user with the proposed nickname. This includes the current nickname of the user requesting the change.

isValidName

public static boolean isValidName(String name)

Determines if a given name is valid or invalid (contains at least one alphanumeric character, and no non-alphanumeric characters). (Nothing to do here.)

Parameters:

name - The channel or nickname string to validate

Returns:

true if the string is a valid name

createChannel

public ResponseSet createChannel(CreateCommand createCommand)

This method is called when a user wants to create a channel. You can ignore the privacy aspect of this method for task 4, but if you choose to do the task 5 Kudos problem, make sure you come back and implement the privacy aspect.

Parameters:

createCommand - The CreateCommand object containing all information needed to attempt channel creation

Returns:

If the channel creation is successful, ResponseSet containing a single Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) message. The recipient should be owner of the new channel. If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.INVALID_NAME if the proposed channel name is not valid according to isValidName(String) (2) ErrorCode.CHANNEL_ALREADY_EXISTS if there is already a channel with the proposed name

joinChannel

public ResponseSet joinChannel(JoinCommand joinCommand)

This method is called when a user wants to join a channel. You can ignore the privacy aspect of this method for task 4. If you choose to do the task 5 Kudos problem, make sure you come back and implement the privacy aspect.

Parameters:

joinCommand - The JoinCommand object containing all information needed for the user's join attempt

Returns:

If the user can successfully join the channel, the ResponseSet should include a Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) response sent to all users in the channel (including the newly joined user). Furthermore, the ResponseSet should include a Response.names(java.lang.Integer, java.lang.String, java.lang.String, java.util.SortedSet<java.lang.String>, java.lang.String) response to the newly joined user containing the names of all users in the channel (also including the newly joined user). If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.NO_SUCH_CHANNEL if there is no channel with the specified name (2) (after Task 5) ErrorCode.JOIN_PRIVATE_CHANNEL if the sender is attempting to join a private channel

sendMessage

public ResponseSet sendMessage(MessageCommand messageCommand)

This method is called when a user wants to send a message to a channel.

Parameters:

messageCommand - The MessageCommand object containing all information needed for the messaging attempt.

Returns:

If the message can be sent, the ResponseSet should include Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) responses addressed to all clients in the channel. If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.NO_SUCH_CHANNEL if there is no channel with the specified name (2) ErrorCode.USER_NOT_IN_CHANNEL if the sender is not in the channel they are trying to send the message to

leaveChannel

public ResponseSet leaveChannel(LeaveCommand leaveCommand)

This method is called when a user wants to leave a channel.

Parameters:

leaveCommand - The LeaveCommand object containing all information about the user's leave attempt

Returns:

A ResponseSet object containing Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) responses to all users in the channel (including the leaving user), informing them that the leave command was successful. If the user was the last member of the channel, then the channel is also removed. If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.NO_SUCH_CHANNEL if there is no channel with the specified name (2) ErrorCode.USER_NOT_IN_CHANNEL if the sender is not in the channel they are trying to leave

inviteUser

public ResponseSet inviteUser(InviteCommand inviteCommand)

This method is called when a channel's owner adds a user to that channel.

Parameters:

inviteCommand - The InviteCommand object containing all information needed for the invite attempt

Returns:

If the user joins the channel successfully as a result of the invite, a ResponseSet containing a Response.names(java.lang.Integer, java.lang.String, java.lang.String, java.util.SortedSet<java.lang.String>, java.lang.String) for all people in the joined channel (including the new user). Furthermore, the ResponseSet should include a Response.names(java.lang.Integer, java.lang.String, java.lang.String, java.util.SortedSet<java.lang.String>, java.lang.String) response to the newly joined user containing the names of all users in the channel (also including the newly joined user). If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.NO_SUCH_USER if the invited user does not exist (2) ErrorCode.NO_SUCH_CHANNEL if there is no channel with the specified name (3) ErrorCode.INVITE_TO_PUBLIC_CHANNEL if the invite refers to a public channel (4) ErrorCode.USER_NOT_OWNER if the sender is not the owner of the channel

kickUser

public ResponseSet kickUser(KickCommand kickCommand)

This method is called when a channel's owner removes a user from that channel. If the user being kicked is the owner, then the channel should be deleted and all its users removed.

Parameters:

kickCommand - The KickCommand object containing all information needed for the kick attempt

Returns:

If the user is successfully kicked from the channel, ResponseSet containing a Response.okay(java.lang.Integer, java.lang.String, org.cis1200.Command) for each user in the channel, including the user who was kicked. If an error occurs, use Response.error(org.cis1200.Command, org.cis1200.ErrorCode) with either: (1) ErrorCode.NO_SUCH_USER if the user being kicked does not exist (2) ErrorCode.NO_SUCH_CHANNEL if there is no channel with the specified name (3) ErrorCode.USER_NOT_IN_CHANNEL if the user being kicked is not a member of the channel (4) ErrorCode.USER_NOT_OWNER if the sender is not the owner of the channel