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)

Wednesday

Morning:

• Review: the Command pattern and its analog in Scheme

• Interfaces

• Anonymous classes

Morning Laboratory:

• Review: finish exercises from yesterday.

Afternoon:

• Modular Definitions of new operations using the visitor pattern
  • Visitors with no arguments
  • Visitors with arguments
  • Visitors as factored closures

Afternoon Laboratory:

You are given the following informal data definition.

A BinaryTree is either:

• a Leaf(c) where c is an int; or
• a Node(b1,b2) where b1, b2 are BinaryTrees

1. Define a composite class hierarchy with the class/interface BinaryTree at the apex representing the preceding data definition. The class should include appropriate constructors and accessors for each concrete class and appropriate definitions of the method toString() method so that:
   • Leaf(c) prints as the String representation of the int value c
   • Node(b1,b2) prints as "(B1 B2)" where B1, B2 are the toString() forms for b1, b2
   Test your code.

2. Define a visitor interface called BinaryTreeVisitor for the BinaryTree composite hierarchy. Using this interface, define visitors to compute:
   • the sum of the tree leaves;
   • the product of the tree leaves;
   • the maximum of the tree leaves; and
   • the height of the tree.
   Write test code for your various visitor operations in either the BinaryTee class or a separate Test class.