CPSC 421-010 Object-Oriented Programming (OOP) Spring 2025

Week 13 Class 24 Thu Apr 10 Posted: Apr 10

After Class

• Project 3: Class Diagram Score and feedback in Brightspace. Not in issues this time.

  Going to work on the Sequence Diagram score and feedback next. Last is the scores for each tag. Note that I am done with the issues.

Announcements

• Project 4 Due Tuesday, Apr 22

• Project 3

  All issues created for tags. Working on feedback on diagrams, and scores on all parts. Reminders:

  • Extension points for XML and the attributes passed as parameters can only be the following:

    XML Extension Point	Attributes
    Start Document
    XML Declaration	version, encoding, standalone
    Element Start Tag	qName, prefix, localName
    Element End Tag	qName, prefix, localName
    Characters	characters
    Attribute	qName, prefix, localName, value
    XML Namespace	prefix, uri
    XML Comment	value
    CDATA	characters
    Processing Instruction	target, data
    End Document

  • It is not a good design to have handlers or callbacks for other parts. Use get accessors if needed.
  • Note that LOC, URL, and other srcfacts concerns are not part of all XML, and the XMLParser should not know about them.

  • Saw lots of public methods, ignoring encapsulation and information hiding. The only methods that should be public are parse(), registering handlers, and perhaps a (very) few get methods. Public methods are for the clients of the class, not for the implementors of the class. There is a cost to every public method. For a real system, all public methods must have:

    • Thorough comments in the include file
    • Thorough external documentation
    • Test cases for each
    • Examples for each
    • Must be maintained throughout the lifetime of the code

    It is easier to just limit the interface (i.e., the public methods) to what is essential to the client code.

• Exercise 66: Dynamic Dispatch

  Feedback is in the file oracle2.txt in the branch feedback in your repository. The oracle2.txt is the difference between the oracle (with the correct answers) and your Base.cpp. If the oracle2.txt is empty, then that means your answer is correct (reflected in your score). Even if your answer is correct the oracle2.txt may show some differences. The differences were manually examined and I used more direct techniques to determine if there were any static dispatch in your answer.

  There is a strong possibility that this will be in a question on the Final Exam.

• Exercise 68: FileIO

  Please read over the feedback in Brightspace. Even if you got a 10 points, there may be feedback as to your comments or coding style.

  • All methods should have a comment before the declaration/definition. This includes constructors and destructors. See the notes for a good comment before a destructor.
  • Do not use the term // virtual ... for a comment of a method (or destructor). The keyword virtual tells us that. The following are examples of substandard comments for destructors:

Agenda

• Exercise 72: Errors and Exception Handling Crossword

• Exercise 73: Exceptions

  Take the code for Exceptions.cpp and perform the following changes:

  • Change the maximum length in function g() to 200 in both the code and the output message
  • Change the "not allowed" value from 50 to 75 in function h() in both the code and the output message
  • Change the domain of function f() to allow the negative value -1 (-2 and smaller is still not allowed)

  Run the program once for each exception, and show that the exception is thrown.

  To demonstrate these changes, you will record a terminal session using asciinema. Submit the terminal session using the form You can use GitHub Codespaces for this as it has asciinema installed.

  Use the GitHub Classroom Exceptions invitation link in Brightspace.

• Notes: Handlers
• Exercise 74: Handlers Crossword
• Notes: Design Pattern Factory Method

• Exercise 75: Design Pattern Factory Method Crossword

  Due by 4:30 pm on Fri Apr 11

• Exercise 76: Design Pattern Factory Method Quiz

  Complete the quiz. Any incorrect answer is a point off out of 10, so answer very carefully.

  You will see the correct responses after the due date.

• Notes: SOLID

Unless otherwise noted, exercises are due by 4:30 pm on Monday, Apr 14