CS586 HW2 Solution

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HOMEWORK ASSIGNMENT #2CS 586; Spring 2010

Due Date: March 24, 2010Late homework 50% offAfter March 28 the homework assignment will not be accepted.

The hardcopy of the assignment must be submitted. Electronic submissions are notacceptable. Notice that the Blackboard homework assignment submissions are only

considered as a proof of submission on time (before the deadline).

PROBLEM #1 (35 points):There exist two servers in the system that provide the following services fro clients:

Server #1:

int multiply(int, int) // two numbers are multipliedint add(int, int, int) // three numbers are added

float add(float, int) // two numbers are added

char next_letter (char) // returns the next letter in the alphabet

char previous_letter(char) // returns the previous letter in the alphabet

Server #2:

float add(float, int) // two numbers are added

int subtract(int, int) // two numbers are subtractedfloat multiply(float, int) // two numbers are multiplied

int multiply(int, int) // two numbers are multiplied


In addition, there are two clients: Client_A and Client_B

Client_A may request the following services:

float multiply(float, int) // two numbers are multiplied

float add(float, int) // two numbers are addedint add(int, int, int) // three numbers are added


Client_B may request the following services:

float add(float, int) // two numbers are addedint add(int, int, int) // three numbers are added

int subtract(int, int) // two numbers are subtracted


Both clients do not know the location (pointer) to servers that may provide these services.

Devise a software architecture using a Client-Broker-Server architecture for this problem.In this design the clients are not aware of the location of servers providing these services.

Provide a class diagram for the proposed architecture. Describe in detail eachcomponent (class) of your design and operations supported by each class using

pseudo-code. In your design all components should be decoupled as much aspossible.

Provide a sequence diagram to show how Client_A gets add(float, int) service.


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PROBLEM #2 (30 points):Consider an application for an intelligent house. The application receives events from

sensors distributed throughout the house. Based on these events the application issues

commands on a humidifier, blinds, and an air conditioner (AC), i.e., turn on humidifier,

turn off humidifier, open blind, close blind, turn on AC, turn off AC. Although several

manufactures (e.g., manufacturer CBA, manufacturer EAB) provide the hardware to buildsuch applications, interoperability in this domain is poor, preventing the mix and match of

devices from different manufactures, and thus making it difficult to develop a single

software solution for all manufactures. The current design is shown below. In this design,

the application (AppControl class) is responsible for identifying objects controlling

humidifiers, blinds, and an air conditioner of the same manufacturer.

CBA-humidif ier

TurnOn( )TurnOff( )

EAB-humidif ier

TurnOn( )TurnOff( )

CBA-Blind

Open( )Close( )

EAB-Blind

Open( )Close( )

CBA-AC

ON( )OFF( )

EAB-AC

ON( )OFF( )

1

Humidifier

TurnOn( )TurnOff( )

*

Blind

Open( )Close( )

1 AC

ON( )OFF( )

AppControl

1

humidifiers

*

blinds

1

air conditioner

In a better design the AppControl class should be shielded from the issues of identifying

objects related to the same manufacturer. Use the abstract factory design pattern to solve

this problem. In your solution the AppControl class should be completely de-coupled

from the manufacturer of the underlying products. In your solution provide:

The class diagram and briefly describe the responsibility of each class and thefunctionality of each operation. You do not have to provide any description for

classes/operations of the above class diagram (only new classes/operations should

be specified using pseudo-code).

A sequence diagram showing how AppControl class will get Humidifier object,two Blind objects, and AC object of the EAB manufacturer and then issue the

following operations on these objects: TurnOn(), Open(), Open(), and ON().


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PROBLEM #3 (35 points):There exist two inventory software systems S1 and S2 that maintain information about

books in several warehouses, i.e., a functional core of each inventory system is to keep

track of the number of books in warehouses. Books may be added or removed from thewarehouse and this should be reflected in the inventory system. Both inventory systems

support the following operations:Operations supported by the inventory system S1:AddBook (isbn, warehouse id) //add a book to a warehouse id

DeleteBook (isbn, warehouse id) //delete a book from a warehouse id

GetNumBooks (isbn) //get the total number of a specified book in all warehouses

IsBook (isbn) //does a specified book exist in the system?

Operations supported by the inventory system S2:InsertBook(isbn, warehouse id) //add a book to a warehouse id

RemoveBook(isbn, warehouse id) //delete a book from a warehouse id

GetNumOfBooks(isbn) //get the total number of a specified book in all warehouses

IsBook(isbn) //does a specified book exist in the system?

The goal is to combine both inventory systems and provide a uniform interface to

perform operations on both existing inventory systems using the strict Layeredarchitecture. The following top layer interface should be provided:

AddBook(isbn, warehouse id) //add a book to a warehouse id

RemoveBook(isbn, warehouse id) //delete a book from a warehouse id

GetNumberOfBooks(isbn) //get the total number of a specified book in all warehouses

RegisterPriorityBook(isbn, minimum level)

UnRegisterPriorityBook(isbn)

ShowPriorityBooks()

Notice that the top layer provides three additional functions (RegisterPriorityBook(),

UnRegisterPriorityBook(), and ShowPriorityBook()) that are not provided by the existinginventory systems. These functions allow watching the status of priority books. The

user/application can register a priority book by providing its minimum level, i.e., aminimal number of books of a specified book that should be present in all warehouses.When the number of books of a priority book (a registered book) reaches the level below

the minimum level, the system should store, e.g., in a buffer, the current status (number

of books) of the priority book. The current status of all priority books whose level isbelow the minimum level can be displayed by issuing ShowPriorityBooks() function. The

function UnRegisterPriorityBook() allows removing a specified book from a list of

priority books.

Major assumptions for the design:

1. Users/applications that use the top layer interface should have an impression thatthere exists only one inventory system.

2. The bottom layer is represented by both inventory systems.3. Both inventory systems should not be modified.4. Your design should contain at least four layers. For each layer identify operations

provided by the layer.5. Each layer should be encapsulated in a class and represented by an object.6. Provide a class diagram for the combined system. For each class list all operations

supported by the class and major data structures. Briefly describe each operationin each class.


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CS586 HW2 Solution

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