Reading material for these exercises:

• Maciaszek: ch. 2.1.3 -2.1.5 (pp 37-45) object concepts, ch 2.2.4 (pp 57-63) class modeling, ch 4.2 class modeling (pp 107-133) especially examples
• Holubs UML reference card is linked on the material page.

Reading material for the next week:

• Maciaszek: ch. 2.2.5 (pp 63-69) interactions, ch 4.3.3-4.3.4 (pp 143-146), ch 5.1.- 5.1.5, 5.1.7 (pp 155-167, 169-172)

Tasks

1. A library collection consists of books and magazines. The magazines are gathered into annual volumes. There may be many physical copies (books) of the same title. The library customers may search for works according to search words (writer, title, name and number of a magazine). In addition, they may borrow books. When a customer borrows a book, his/her name, the ID of the borrowed book, the date and the due date are recorded. The customer may also make a reservation for a title that is not available at the moment. The reservation contains information on the customer, the title and the date of reservation. Magazines cannot be borrowed, they can only be read in the library. Draw a class diagram that describes the data contents of the system. Pay special attention to whether the existence of a class depends on another class. Use compositions to present possible existence dependencies.



2. Create an object diagram corresponding to your class diagram of the library, describing the following things: John Smith (ID 99999) has borrowed two books: Dostoyevski's Crime and Punishment (ID 12345) and Linnaeus' Species of Plants (ID 67890) on 30th March 2000. At the same time, he has reserved the book Wildlife in Savo (67891), edited by Blossom Hayfield. Jane Jones has borrowed Herman Hesse's Steppenwolf (54321) and another copy of Dostoyevski's Crime and Punishment (12344). In addition, she has reserved Dostoyevski's The Brothers Karamazov

3. Travel agency FarAway needs a system for marketing its products in WWW. The users should be able to view the information and also to make reservations on the trips and to post comments about their trips. Each tour has a description consisting of a general description of the destination and a description of the accommodation choices. The general description contains descriptive text and pictures, the flight schedule and the dates of departures. Each accommodation choice description contains the name and address of the hotel or the apartment hotel, a description of the types of rooms or appartments and their number, the base price for a one week tour (for a room type and a given number of persons), the price of extra beds and their maximum number, and the price for an extra week. Reservations are booked for the selected room type and identified by reservation number. A reservation specifies the name and address of the customer, the names and dates of birth for the travellers, the departure date, the duration of the trip, and the reservation's state of processing. Underline all class candidates in the previous text. Evaluate their suitability for classes based on the following criteria:

• do the instances of the class have attributes that are necessary in the system
• is the information about the existence of instances of the class necessary
• is the 'class' essential for the system
Select the classes.

Candidate	Comment	Decision
travel agency	only one instance, no attributes spesified	no
product	a generalisation, synonym to trip or tour	no
trip	tour taken, could be synonym to reservation	no
comment	feedback to be collected, object	yes
tour	product to be sold, object	yes
reservation	deal made, essential object	yes
destibation=resort	there are resort specific information. This should be selected if there are more than one types of tours to the same resort, otherwise resort information may be attached to tour (we assume one one type of tour for each resort)	no
traveller	customer who travels,role	no
accommodation choice	targets for reservations	yes
descriptive text		no
picture	might be technically object, but logically attribute	no
flight schedule	collection of information, we are more interested in individual departures	no
departure	potential starting time, essential	yes
hotel	participant in the process	yes
apartment hotel	subclass of hotel, non-essential	no
room type	many attributes	yes
customer	customer,ok, but this has to meaning also paying customer association	yes

The description text above does not tell it directly but one rese4rvation may contain many room resrvations and many flight reservations. these should also be considered as class candidates and selected as classes.

When we try to determine how the selected classes are associated to each other we obtain the following diagram:



4. Complete the class model of task 1 by including attributes and associations. Present the result as an UML class diagram.



5. The products of Alfonso's pizza service include pizzas, sandwiches, salads, pastas and drinks. Each product type may be available in different size of portions. The prices depend on the product and the size of the portion. Extras like carlic, parmesan cheese, and mushrooms are also available. Extras are priced separately from products. Alfonso's product catalog explains in detail what ingredients are used in each product. Extras are included in ingredients. All ingredients, such as pizza dough, are not anyhow sold as extrass. An order may contain many portions each with none or many accompanients. The information system should take care of the maintaining of the product data and the pricing information. It should also support the processing of the orders. Draw an UML class diagram to describe the information contents of the system. Suplement the above description with the missing details.



Pizza diagram as PLA-file for Plastic Lite

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Harri Laine