Description
An important technique in the study of Object-Oriented Programming is the use of delegation to
replace class inheritance. A systematic approach for this transformation was given in Lecture 5.
Apply this approach to the program Delegation.java located at Piazza Resources
Assignments. This program defines classes A, B, C, D, E, and F. The result of your
transformation should be classes called A2, B2, C2, D2, E2, and F2 which correspond to
classes A, B, C, D, E, and F respectively, but do not make use of class inheritance.
In order to develop the transformation, you need to define one interface for each class. Name
these interfaces IA, IB, IC, ID, IE, and IF. Classes A2, B2, C2, D2, E2, and F2 must
implement interfaces IA, IB, IC, ID, IE, and IF respectively. As noted in Lecture 5, you
may use optimize the interfaces to remove redundancies.
The file Delegation.java contains the definitions of classes A … F and also a driver class
called Delegation. It also contains the outline of the classes A2 … F2. Define the interfaces
IA … IF and the classes A2 … F2 in the same file. Run the program through JIVE and
save the object and sequence diagrams as files named A2_obj1.png and A2_seq1.png
respectively. For the object diagram, choose the ‘Objects with Tables’ option.
Important: Full credit will be given only if the transformation is done in a systematic way: In
addition to the definition of the interfaces, the delegation hierarchy should be defined; new
variables this2 and super2 should be introduced to model this and super respectively; and,
delegation and protected abstract methods should be implemented as required.
What to Submit. Prepare a top-level directory named A2_Part1_UBITId1_UBITId2 if the
assignment is done by a team of two students; otherwise, name it as A2_Part1_UBITId if the
assignment is done solo. (Order the UBITIds in alphabetic order, in the former case.) In this
directory, place Delegation.java, obj.png and seq.png. Compress the directory and
submit the resulting compressed file using the submit_cse522 command. Only one submission
per team is required.
Part 2: Generic External Iterator Design Pattern.
Will be assigned on Friday, September 21.
End of Assignment 2
