1. Introduction to OO Program Design
Software College of SCU
Instructor: Shu Li
Review

2. Unit 1 Class Design
Basic Console I/O
StringTokenizer
Exception
UML class diagram

3. Console I/O
private static BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in)); private static PrintWriter stdOut = new PrintWriter(System.out, true); private static PrintWriter stdErr = new PrintWriter(System.err, true);
true, autoflush

4. StringTokenizer
import java.util.*; StringTokenizer tokenizer = new StringTokenizer(data, "_"); tokenizer.countTokens(); //number of tokens while(tokenizer.hasMoreTokens()) { String token = tokenizer.nextToken(); } // traverse each token

5. Exception (checked/unchecked)
try { stdErr.print("Enter an integer > "); stdErr.flush(); // print without auto flush return Integer.parseInt(stdIn.readLine()); } catch (IOException ioe) { ioe.printStackTrace(); System.exit(1); // terminate the program } catch (NumberFormatException nfe) { stdErr.println("Invalid number format"); }

6. UML class diagram (Inheritance/Association)
Solid line: extends
Dashed line: implements

7. Unit 2 Class Implementation
equals()/toString()
Vector/ArrayList
JDK 5
Vector<String>
ArrayList<String>
For each loop (Iterable interface/iterator method)
JUnit
Design Pattern

8. Vector and Iterator

9. methods defined in class Vector
Vector(). Constructs an empty collection.
int size(). Returns the number of objects in the collection.
boolean isEmpty(). Determines if there are no objects in the collection.
boolean contains(Object elem). Determines if the specified object is an element of the collection (as determined by the method equals).
boolean add(E o). Appends the specified object to the end of the collection.
void add(int index, E element). Inserts the specified object at the specified index position, shifting any subsequent elements to the right (adds one to their indices).
E get(int index). Returns the object at the specified position.
public E set(int index, E element). Replaces the element at the specified index position with the specified object.
public boolean remove(Object o). Removes the first occurrence of the specified object (using method equals), shifting any subsequent elements to the left (subtracts one from their indices).
E remove(int index). Returns the object at the specified position after first removing it from the collection and shifting any subsequent elements to the left (subtracts one from their indices).

10. Methods Defined in Class ArrayList
ArrayList(). Constructs an empty collection.
int size(). Returns the number of objects in the collection.
boolean isEmpty(). Determines if there are no objects in the collection.
boolean contains(Object elem). Determines if the specified object is an element of the collection (as determined by the method equals).
boolean add(E o). Appends the specified object to the end of the collection.
void add(int index, E element). Inserts the specified object at the specified index position, shifting any subsequent elements to the right (adds one to their indices).
E get(int index). Returns the object at the specified position.
public E set(int index, E element). Replaces the element at the specified index position with the specified object.
public boolean remove(Object o). Removes the first occurrence of the specified object (using method equals), shifting any subsequent elements to the left (subtracts one from their indices).
E remove(int index). Returns the object at the specified position after first removing it from the collection and shifting any subsequent elements to the left (subtracts one from their indices).

11. Code Demo See: LibrarySystem import java.util.*; public class Client {
private String name;
private Vector accounts;
public Client(String initialName) {
name = initialName;
accounts = new Vector(); }
public void addAccount(BankAccount bankAccount) {
accounts.add(bankAccount);
public Iterator getAccountIterator() {
return accounts.iterator();
public int getNumberOfAccounts() {
return accounts.size();
See: LibrarySystem

12. JDK 5
public class Client implements Iterable<BankAccount> { … private Vector<BankAccount> accounts; public Client(String initialName) { accounts = new Vector<BankAccount>(); } public Iterator<BankAccount> iterator() { return accounts.iterator(); for (BankAccount account : client) { totalBalance += account.getBalance();

13. Creating a test class in JUnit
Define a subclass of TestCase
Override the setUp() method to initialize object(s) under test.
Override the tearDown() method to release object(s) under test.
Define one or more public testXXX() methods that exercise the object(s) under test and assert expected results.

14. JUnit Methods assertEquals(x, y) – Test passes if x and y are equal
x and y can be primitives or any type with an appropriate equals method
Three argument versions exist for floating point numbers
assertFalse(b) – Test passes if boolean value b is false
assertTrue(b) – Test passes if boolean value b is true
assertNull(o) – Test passes if object o is null
assertNotNull(o) – Test passes if object o is not null
assertSame(ox, oy) – Test passes if ox and oy refer to the same object
assertNotSame(ox, oy) – Test passes if ox and oy do not refer to the same object

15. Design Pattern

16. Singleton Pattern
Constructor private

17. Strategy Pattern

18. Composite Design Pattern
To allow clients to treat both single components and collections of components identically
To define recursive data structures such as trees
uses
Leaf
operation()
Component
Composite
add(Component)
remove(Component) *
Client 18 18

19. Decorator Pattern

20. Observer Pattern

21. Unit 3Advanced Class Implementation
3.1 Input and Output Programming

22. Abstract Classes
InputStream & OutputStream
Reader & Writer

23. Line-oriented I/O