TeachJava!

Resources

• Class Notes (also available in postscript)
• Java Design Recipe
• Java 1.3 library documentation (including Swing)
• Java 1.3 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 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)
  
  
• 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
    • Simple Java expressions over primitive types
      • familiar algebraic notation adapted to ASCII + four C idioms: ! == && ||
      • precedence
  • Java Program Structure
    • Collection of classes rather than procedures
    • Sequence of statements rather than an expression
  • Defining operations involving primitive data using static methods
  • Other important built-in data types
    • String
    • Equality operator vs. the equals method
  • Java classes
    • generalization of Scheme structs
    • members are either fields or methods (code)
    • constructors and accessors
    • classe are organized as a hierarchy
    • printable object respresentations (toString())
    • Simple examples: Entry class, CityEntry class

Overview: finger exercises in sections 1.1 through 1.4. The file DeptDir is located at the URL http://www.cs.rice.edu/~cork/teachjava/code/DeptDir.java. Use the online version of the notes to find exercises 1.4.2, 1.4.3, and 1.4.4.

Assigment:

• 1.1.1, 1.2.2, 1.2.3, 1.2.4, 1.2.5, 1.2.6, 1.2.7.1, 1.2.7.2, 1.2.8, 1.4.2, 1.4.3, 1.4.4

Afternoon Lecture

• The Composite Pattern and Mixed Data
  • Data variants (employee records)
  • Inductive data definitions
• Data-directed Programming in Java
  • Review of the structural design recipe from Scheme
  • Concrete classes in Java correspond to structures in Scheme
  • Using the composite pattern to represent mixed data
  • Canonical example: DeptDirectory
  • Standard class methods: constructors, toString, and equals
  • Using the interpreter pattern to represent structural recursion

Afternoon Laboratory

Overview: Exercises 1.4.1, 1.5