TeachJava!

Resources

• Class Notes (also available in postscript)
• Java Design Recipe
• Java 1.4 library documentation (including Swing)
• Java 1.4 general documentation
• Sun Java Tutorials
• Thinking in Java by Bruce Eckel (available for free downloading in PDF format)

Monday

Morning Lecture

• Welcome to TeachJava!

• Guiding Vision: once you understand how to design programs in Scheme, object-oriented programming in Java is easy.

  Programming in Java  =  Programming in Scheme + object-oriented transformations (design patterns)
  

• Goals of TeachJava!
  • to promote the creation of high school curricula on object-oriented programming in Java that build on TeachScheme
  • to show that the programming principles from TeachScheme apply equally well to object-oriented programming in Java
  • to focus on object-oriented design principles, which expand on the programming principles taught in TeachScheme
  • to make the material Java reference books and textbooks such as Thinking in Java easily accessible to participants
  
  
• Non-Goals of TeachJava!
  • to teach every Java language feature
  • to provide a whirlwind tour of the Java GUI libraries
  
  
• DrJava vs. DrScheme
  • DrJava supports EXACTLY the same user interface as DrScheme
  • DrJava lacks
    • language levels (coming in Spring 2003)
    • stepper (coming ?)
  • DrJava offers
    • integrated unit testing
    • a full-featured debugger
    • support for generic extensions of Java (JSR14)
    • open source
  
  
• Fundamental Differences Between Scheme and Java:
  • Java uses C-style syntax: wordy, wordy, wordy
  • Java relies on object-oriented rather than procedural program organization
    • What is an object?
      • a collection of variables called fields to represent the properties of a particular physical or conceptual object
      • a collection of designated operations called methods to access and modify the fields
    • Example: maintaining a directory for Rice Computer Science Department. Each entry in the directory will contain a person's name, office address, and phone number. In Java, we can represent each entry as an Entry object consisting of three fields (name, address, phone) and the operations to access those three fields. Let's summarize the form of an Entry as a table:

      Fields:
String name;
String address;
String phone;

Methods:
String getName();
String getAddress();
String getPhone();


    • Most visible difference: method calls instead of procedure calls: e.getName() instead of (getName e)
  • Do Finger Exercise 1.2.1.
  
  
• Fundamental Similarities:
  • Both languages support essentially the same view of data ("data model"); there is a one-to-one correspondence in data forms
  • Both languages are safe and rely on garbage collection
  • All of the programming principles that you learned for Scheme apply in the context of Java
  
  
• Elementary Mechanics of Java
  • Primitive data types and expressions
    • Eight basic types, but only three really important ones (int, boolean, double)
    • Simple Java expressions over primitive types
      • familiar algebraic notation adapted to ASCII + four C idioms: ! == && ||
      • precedence (see notes for table)
      • conditional expressions
        (if a b c) is written as a ? b : c
      Do Finger Exercises 1.3.2.1, 1.3.2.2, 1.3.2.3., 1.3.3.1, 1.3.3.2, 1.3.3.3
  • Java assignment statements
    Do Finger Exercise 1.3.4.1
  • Java Program = collection of class definitions (nothing else!)
    Do Finger Exercise 1.3.5.1
  • Program constants are static final fields of classes
    Do Finger Exercise 1.3.6.1
  • Capitalization and commenting
    Do Finger Exercise 1.3.7.1
  • Java class definitions
    • generalization of Scheme structs
    • members are either fields or methods (code)
    • Constructors and accessors
      Do Finger Exercise 1.5.2.1
    • Instance methods
      Do Finger Exercise 1.5.3.1
    • Printable object respresentations (toString()) Do Finger Exercise 1.5.4.1
    
    
  • Class Hierachies and the Union Pattern
    • Classes are organized as a hierarchy
    • The Union Pattern
      • Data variants (directory entries)
        • Simple examples: CityEntry class with three subclasses
          Do Finger Exercise 1.6.1
      • Member hoisting
        Do finger Exercises 1.6.1.1, 1.6.1.2

  ---

  Morning Laboratory:

  Overview:

  Assigment:
  

  • Read Section 1.4.3 in the online class notes and do Finger Exercise 2.
  • Do the Optional Finger Exercise in Section 1.5.1 of the class notes.
  • Do the Finger Exercise in Section 1.5.3 of the class notes.

  Afternoon Lecture

  • The Composite Pattern
    • Class Hierarchy Representing an Inductive data definition
    • Identical to Union Pattern except for the presence of self-reference
  • Basic Object-Oriented Program Design
    • Review of the structural design recipe from Scheme
    • Applying the design recipe to Java
    • Extended Example: integer lists
    • Maintaining sample test data
    • Helper methods and visibility

  Afternoon Laboratory

  Do the finger exercises in Section 1.6 of the class notes.