Advanced OOP System Implementation in Java
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Learn about advanced object-oriented system implementation in Java covering linked list, class structures, and depth information system setup. Implement Lecturer, Student, Module, and Department classes with their respective variables and methods.
Advanced OOP System Implementation in Java
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Presentation Transcript
Advanced Object Oriented Systems (CM0318) Introductory Lecture (Last modified: 28th January 2002)
Suggested linked list implementation • 2 classes: MyLinkedList and MyLink(NB actually Java provides a class LinkedList)
MyLinkedList • instance variables: • MyLink first • MyLink last • int size • methods: • MyLinkedList() • void add(Object element) • Enumeration elements() • int size() • ...
MyLink • Instance variables • MyLink next; • Object element;
Suggested Deptl. Info. System implementation • Classes include: • Lecturer • Student • Module • (Department)
Lecturer • instance variables: • String name (or could be split up into parts) • Vector modules_given • methods: • void add_module(Module m) • Enumeration all_modules() (or Vector?) • (optionally things to set the name, etc., which could then be made private)
Student • instance variables • String name (or could be split up into parts) • int student_number (or should it be a String?) • Vector modules_taken • methods • things to add a module, etc., similar to Lecturer
Module • instance variables • String module_code • String module_title • methods • accessors (set code, etc.)
Department • instance variables • Vector lecturers • Vector students • Vector available_modules • methods • Vector lecturer_names() (or Enumeration?) • Vector all_students()
Note Well • Always more than one way to model a problem! • Because of Java’s type system, collections like Vectors are horrible to use - but better than nothing! E.g. to iterate through the lecturers’ names you’ll need code like this: Enumeration e = lecturers.elements(); while (e.hasMoreElements()) { do_something_with( ((Lecturer) e.nextElement()).name);}
Topics • Why OO? • intuitive • modelling • software quality • reuse • Features of OO that give these qualities
Java • Using the libraries • Modelling non-trivial problems
Design • ACJ: • Design by contract • AIA: • Methodologies • Communicating design • CRC Cards • UML • Design patterns
Other OO languages • Dynamically typed languages • Smalltalk • Self (classless!!) • Statically typed languages • C++ • Eiffel (NB supports design by contract)
Building systems interactively • ACJ: • The Smalltalk programming environment approach • AIA: • The CASE approach
Distributed objects - CORBA • Language & platform independence • Wrapping legacy applications
Implementation of OO languages • Memory management • Virtual machines • Bottlenecks & clever ideas!!