The Server Group

CS 495

Professor Steflik

Fall 2004

Victoria Toujilina Ryan Leslie Justin Phillips Qing Zhang Yu Ting Oren Kashi Mark Bojdak Farshid Firouzeh Leonard Wong Brian Juba

Server Integration Responsibility

Victoria Toujilina

CS 495 Professor Steflik

Fall 2004

Statistics

Client3Protocol & Threads

DatabaseObject

ChallengeDispatcherDatabase

Client2WatsonGameServer

Player Maintenance & Character Creation

Client1Login/Logout

Scoring

Handler for Life Challenges

Server Group Tasks

Server Protocol HandlingRyan Leslie

CS 495 Professor Steflik

Fall 2004

Overview 1. WGListener object waits for client-initiated connections2. When a connection is established, a WGConnection object is

created to handle the connection3. WGConnection waits for client input4. Input lines are parsed for commands by WGCmdParser.

Each command is encapsulated in a WGCommand object 5. For each command, the appropriate command handler is

triggered6. The command handler writes results back to the client

Overview (Cont.)

See Loi-Server_Protocol_Handling.doc for further details

Commands Commands currently supported by protocol handler

Login / Logout LoginLogout handler still undergoing development

Create Player CharacterCreation handler still undergoing development

Load Player Need handler in GameKeeper (or elsewhere) to create a Player object given a username

Load Game State No handler implemented

Save Player State No handler implemented

Load Challenge ChallengeDispatch handler still undergoing development

Complete Challenge Scorer handler still undergoing development

Commands (Cont.) Some commands still pending support by

protocol handler Move Player Position Get Knapsack Update Knapsack Get Player Statistics (GPA, health, etc.)

Implementation Issues WGConnection lacks class variable to associate each

connection with a player Needed so that certain commands can be associated with

a particular player Can be set by LoginLogout object when a user

successfully logs in Protocol Handler lacks protection against malformed

commands This can cause command handlers to malfunction Problem can be resolved in WGCmdParser

Server Thread HandlingJustin Phillips

CS 495 Professor Steflik

Fall 2004

Current Implementation WatsonGameServer.java

Creates instances of all objects needed to allow a player to log in.

Runs the WGListener and ChallengeDispatcher on separate threads.

WGListener.java Creates a server socket that listens on port 1500 by default A thread running the WGConnection object is created for

each new connection request the server receives

Design Goals Problem: Server can only support an

estimated 30 to 50 connections at once Performance degradation noticeable as number of

connections increase This number will vary depending on what other

processes are running on the machine and the amount of available memory and CPU speed

Design Goals Solution: Limit the number of connections

server will accept Allow this number to be set through a parameter Send “Connection Failed: too many users”

response to any client attempting to connect when limit has been reached

Count the active connections, incrementing the counter when a new connection is established and decrementing the counter when a user logs off.

Other Goals Support thread handling in order to aid

development in other areas of the WAG Update documentation on thread handling Answer questions regarding thread handling

Scoring Scheme and Implementation

Ryan Leslie

Justin Phillips

CS 495 Professor Steflik

Fall 2004

Current Scheme Player completes challenges and receives a

grade for each. To complete the game the player must earn a

4.0 GPA upon completing all challenges Implemented in Scorer.java

New Scoring Scheme Object Of the Game

Accumulate at least N credits Accumulate a minimum number of college

experience points Earn a minimum GPA of X

X will be based on game difficulty Use player intelligence?

New Scoring Scheme Challenges divided into two categories

Student Life Challenges Consists of all challenges not related to academic knowledge Upon completion the player will gain college experience points

Academic Challenges Test subject knowledge Upon completion the player will receive

A grade that is factored into the GPA 4 credits for completing the challenge if the grade is passing

New Scoring Scheme Academic Challenges must be met in a progressive

manner Each academic challenge requires a minimum number of

accumulated credits before it may be attempted Challenges may be retaken

Each grade for an academic challenge is averaged into the cumulative GPA Allows player to increase GPA

A player may not receive credit or experience points for a challenge more than once

Implementation Details Database Group

Shall support the following character attributes Experience Points GPA Cumulative Credits

All other character attributes will not be utilized this semester

Implementation Details Client Group

Should provide a means to display the previously mentioned character attributes

Game Statistics

Qing Zhang

CS 495 Professor Steflik

Fall 2004

Game Statistics General Statistics

Number of Players Number of Professors Number of Locations

Game Statistics Player Statistics

Identification Number Name GPA Current Status

Game Statistics Professor Statistics

Identification Number Name Courses Teaching Office Location

Game Statistics Locations Statistics

Location ID Number Location Status

Challenge or Help History Statistics

Positions of Locations

Game Statistics Usage of game statistics

Player’s Privilege Professor’s Privilege

Challenge DispatcherYu Tak Ting

CS 495 Professor Steflik

Fall 2004

Challenge Dispatcher Its role is to contact the database object and obtain

information about challenges to dispatch back to a client, based on the coordinates of a hotspot that client has bumped into.

Only one will exist, created by the WatsonGameServer class and instantiated to run in its own thread.

Multiple threads are created by the WatsonGameServer when players request for challenges.

Server Side Duties Get information from Client. Check that the player can take the test. Obtain questions from Database for the

specific test. Update player statistics depending on the

result of the test.

Client Side Duties Challenge Hotspot Coordinates Send player information to server. Execute the test. Send test result to the server.

Database Duties Decide on the database structure of the

questions. Format of the questions Different Majors

Details Will a player be allowed to take a test again? Show correct answer or not? How much information does the client have to

send over to the server? How much information does the server have to

update Knapsack,Major,PlayerID, Test Result

Possible Enhancements Different levels of difficulty in questions Hints for questions – additional database

storage Variable length and difficulty tests.

Handler for Client Generated Challenge

TriggersOren Kashi

CS 495 – Professor Steflik

Fall 2004

Handler for client generated challenge triggers

New addition of Student Life challenges Need a different method of dispatching the

challenges Student Life challenges

Broken hard disk Injuries Virus deletes your computer Etc…

How to “trigger” the trigger? Bump into a wall. Get stuck in the

elevator. Drop your laptop. Failing your test.

Implementation The client generates a request for a challenge. The protocol handler deciphers request and creates

an instance of the handler. The handler will then query the database and return

the challenge to the protocol handler. The protocol handler will then pass the challenge

off to the client.

Flow

Client Server

Handler DB

Future aspects to think about How to check if

student completed the task?

Is the task mandatory, or optional?

How to implement the point system for each challenge?

Login/Logout Support

Mark Bojdak

CS495 Professor Steflik

Fall 2004

How it’s designed to work… Login

After the user enters a username and password, a request to logon to the server is made

When the client makes this request, it passes two strings to the server (username and password)

CLIENT SERVER DATABASEUsername/Password

Request

How it’s designed to work… The server then queries the database to see if a

valid username and password were entered Database returns a value to the server, indicating

if it was successful -1 invalid username 0 valid username / invalid password 1 successful login

SERVER DATABASE

Request

Response

-1 or 0 or 1

CLIENTUsername/Password

Request

How it’s designed to work… Logout

When the user logs out, the database will be updated with the latest game attributes (game statistics) unique to the user

When the same user returns to the game, they will inherit all of the attributes from the previous time they played

Current Problem Server doesn’t query the database to verify

whether a valid username and password were entered As a result, any user can login, regardless of the name and

password entered No attributes are assigned to the player

SERVER DATABASE?

?

CLIENTUsername/Password

Request

No Communication

Solutions to be Implemented Query the database

A request must be sent to the database to verify both username and password entered

If both are valid, load all of the user’s game attributes

Format of data Verify the data being sent and received by the database is of the proper

format

SERVER DATABASE

?

?

CLIENTUsername/Password

Request

Add Request

Must be -1, 0, or 1

Player Maintenance & Character Creation

SupportFarshid Firouzeh

CS 495 Professor Steflik

Fall 2004

Player Maintenance Task 1: Ensuring no duplication of same

player.

Possible Solutions?

- Check Database

- Make a quick checker via server code,

potential list (Is it faster? More efficient?)

Player Maintenance Task 2: Dealing with players that have not

played for a while.

Possible solutions?

-Use Java Time() functions to define a

counter. This counter will keep track of

when players last logged on.

Task 2 continued - After counter expires, player considered

inactive. Therefore, must erase player’s

history from database.

Previous Coding Gamekeeper.java - function addNewPlayer (to the game) 1.) Doesn’t check for already-existing players. Need to be Fixed?

Add counter code here? Or elsewhere?

Suggestion for Database Group: - add “inactive” attribute to NPCharacter Table?

Character Creation Support Modification of existing attributes for

players? Attributes will differ for CS, ME, EE

students? Main concern : Updating DataBaseObject,

CharacterCreation code.

Previous Coding CharacterCreation.java

- Checkuser() : Not working? Put in right

file? (GameKeeper, perhaps?)

- Other than this, CharacterCreation

seems fine. Maybe brushing up of

previous code plus code to add as is

needed.

Previous Coding DataBaseObject.java

1.) playerExists() : Not working? Needed in

this file?

2.) createCharacter() : Puts all info in

database. Most likely needs update.

Challenge Dispatching

Leonard Wong

CS 495 Professor Steflik

Fall 2004

Design Inputs Player bumps into challenges triggers event

that sends server a request for challenge Coordinates or code of challenge is received by

server Server receives the client’s answer to the

challenges

New Design Inputs Timer on client side fires a trigger that sends

server a request for challenge Code for challenge is received by server

Server receives messages that challenges have been completed

Design Processes Server must determine if client qualifies for

challenge Server retrieves “level status” of the client Server compares this to the level of challenge the

client is requesting If client qualifies, retrieve challenge data (actual

question, possible answers, correct answer) Match client answer to retrieved correct

answer

New Processes Server retrieves information for physical

challenges from database Client side keeps track of challenge status

When message received that challenge has been completed: Figure out what attributes will be updated and by how

much

Outputs The actual challenge information to the Client

Question Possible Answers

Update “level” information from answering challenges correctly

New Outputs Student life challenge information

Actual challenge description Reward for challenge?

Track physical challenge progress Collecting number of items Speaking with specific faculty etc

Update player attributes upon challenge completion

Open for discussion… Player attributes?

What role will they play What type of attributes How to increment them

Type/Nature of “student life” challenges Table names and description of attributes in the

database Penalties for failing challenges or answering

challenges incorrectly?

Game Status Info Request Handler

Active Player and Database Object Support

Brian Juba

CS 495 Professor Steflik

Fall 2004

Game Status Handler Will give statistics to the user. About the Game

# of players currently, # of all players # of sessions made total

About the User Last login Total time played # of sessions they’ve had

To Do This… Need to add fields to the character table

Last login, # of sessions, active (0 or 1), time Create a handler class that computes numbers

based on data from the database object. Then pass the information to the client to pop

up a window with the stats. Add a command to the protocol, Get Stats

Database Object Support Acts as an interface to the

database. Creates a common object

that all the handlers can access.

Handles all the types of queries. SELECT, UPDATE,

DELETE, INSERT

Server

Database Object

Database

Structured Query Language (SQL)

ANSI Standard – but there are many different variations.

When a query is performed a result set is returned.

Last Name First Name

Martin Curtis

Walnuts Paully

“SELECT Last Name FROM Persons”

Last Name

Martin

Walnuts

Persons

Adding MySQL WAG currently runs off a MS Access database. New version will run Access for a local game,

while MySQL for a remote game. Need to create a flag to specify. Game should behave the same way using both

databases. SQL queries already created might have to

change due to variations between them.