Musixscore.com is an online service providing sheet music to customers. On the “browse music” Web page, customers select a genre of music from a drop-down list. The Web page uses Ajax to obtain a list of performers, musicians, or groups that match the genre, which is formatted as a dropdown list. When a selection is made from the performer’s drop-down list, the Web page uses Ajax to display a third drop-down list displaying all the CDs or other works of the performer. When a CD is selected, the Web page uses Ajax to obtain all the songs on the CD in a fourth drop-down list. The viewer may make multiple selections. When the Add to Shopping Cart image is clicked, the songs are added to the shopping cart. The viewer may change any of the drop-down lists to select additional sheet music, and the process is repeated.

a. Write a use case description for the Browse Music Score use case, representing this activity.

b. Draw a sequence diagram using boundary, control, and entity classes for the Musixscore Web page.

c. Write a list of the messages, names, and the parameters, along with the data types, that would be passed to the classes and the values (with data types) that are included with the return message. Make any assumptions you need about the data.

d. Create a class diagram for the entity classes used in the sequence diagram.