Week 4’s lecture by Judy got slightly deeper into the concept, design and implementation of objects. Again, I am finding that these lectures are moving very slowly and feel that prospective students should be given a chance (if they want) to demonstrate that they are not complete novices. However, this from an administrative point of view would probably be impossible and running through an introductory class will ensure that all the basic concepts (and more importantly, conventions) are clearly understood. So the only thing to do is get good marks and have a point to argue from for next semester.
The lecture started of defining the terms Abstraction and Modularization referencing their relevance to programming with a simple clock program. I felt this was valuable but could have been so much more valuable if we had gone a few steps further and show the practical applications for modularization and decoupling by making the clock program work and re-using the modules in different examples. In this example, Class Diagrams and Object Diagrams where covered (straight out of bluej).
Next came Primitive Types vs Object Types, specifically the differences in memory allocation (objects reference). I guess this will be a more interesting point when programming in C and the Garbage collector does not destroy unreferenced variables. Formal Parameters, Actual Arguments, Internal and External method calls followed, these were all consistent with what I have seen previously and now feel very intuitive. The only point where I felt uncomfortable was where methods contained local variables with the same name as their Formal Parameters, necessitating the need for this.variable = variable notation. Seems much easier to me to avoid double naming.
The really key topic covered in the lecture and in the tutorials was the coding conventions: 70.40.214.44/Java_coding_standards.pdf
I need to update my existing habits to meet these standards (definitely a good thing).. means alot more indenting.
I will start reading through the text book more for this subject and continuing my own Java development. This should suffice until next semester or the 3rd when I hope we have the chance to do some challenging implementations.
Pearl of the Week: My first attempt at using Java Objects and a MySQL DB, hope to learn how wrong it is in the near future.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | /** Constructs a Book with bookID. @param ID the Book ID number */ public Book(int ID) throws SQLException, IOException, ClassNotFoundException { SimpleDataSource.init(); Connection conn = SimpleDataSource.getConnection(); try { java.sql.PreparedStatement stat = conn.prepareStatement("SELECT * FROM books WHERE book_ID = ?"); stat.setInt(1, ID); ResultSet rs = stat.executeQuery(); rs.next(); title = rs.getString("title"); author = rs.getString("author"); total = rs.getInt("total_pages"); current = rs.getInt("current_page"); path = rs.getString("path"); date = rs.getString("date"); genre = rs.getString("genre"); notes = rs.getString("notes"); } finally { conn.close(); } } |
Haha there already a few bit there that are breaking format conventions already…. D:
Note, for some reason the code box is automatically removing indentation. The code box was made using a WordPress plugin: http://kpumuk.info/projects/wordpress-plugins/codecolorer/