1. Graphics Graphics Java Vectors Java Enumeration Graphical Spreadsheets
Java Pixels and Coordinate System
ObjectEditor Shapes
Java Vectors
Variable-Sized Instances
Java Enumeration

2. A Square With Text

3. Java Coordinate System
(3,2)
(0,0) X
pixels Y

4. Describing Shapes x1, y1 x2, y2 Bounding Rectangle h1 h2 w1 w2 x4, y4
hello h3 w3

5. A Square With Text import shapes.RectangleModel;
import shapes.TextModel;
public interface SquareWithText {
public RectangleModel getSquare();
public void setSquare(RectangleModel newVal);
public TextModel getText (); }

6. A Square With Text import shapes.RectangleModel
import shapes.TextModel
public class ASquareWithText implements SquareWithText {
RectangleModel square;
TextModel text;
… // constant declarations
public ASquareWithText() {
square = new RectangleModel (INIT_X, INIT_Y, INIT_SIDE_LENGTH, INIT_SIDE_LENGTH);
text = new TextModel(TEXT_STRING);
placeText(); }
void placeText() {text.setCenter(square.getCenter());}
public RectangleModel getSquare () {return square;}
public void setSquare (RectangleModel newVal) {
square = newVal;
public TextModel getText () {return text};

7. ObjectEditor Classes x1, y1 w1 h1 w2 h2 x2, y2 Bounding Rectangle
RectangleModel r = new RectangleModel(x1, y1, h1,w1)
LineModel r = new LineModel(x2, y2, h2,w2)
x5, y5
hello
TextModel r = new TextModel(x4, y4, h4,w4)
PointModel r = new PointModel(x5,y5))
OvalModel r = new OvalModel(x3, y3, h3,w3)

8. AWT Classes x1, y1 w1 h1 x5, y5 Point r = new Point(x5, y5))
Rectangle r = new Rectangle(x1, y1, h1,w1)
r.x
 x1
r.x
= x4
p.x
 x1
Dimension d = r.getSize()
d.width
 w1
Point p = r.getLocation()

9. ObjectEditor Vs AWT Classes

10. Methods on ObjectEditor Classes
getX(), setX(), getY(), setY(),
getWidth(), setWidth(),
getHeight(), setHeight.
getCenter(), setCenter(),
getNWCorner(), setNWCorner(),
getNECorner(), setNECorner(),
getSWCorner(), setSWCorner(),
getSECorner(), setSECorner(),.
isFilled(), setFilled()
getColor(), setColor()

11. Shapes Demo

12. Variable-Size Collection
Plotting Points
Variable-Size Collection
History
Elements accessed by ObjectEditor
Conventions for exporting elements

13. Conventions for Variable-Sized Collection
Write method
import shapes.PointModel;
public interface PointHistory {
public void addElement (int x, int y);
public PointModel elementAt (int index);
public int size(); }
Arbitrary Type.
Read methods

14. Read Vs Write Methods Read Methods Write Methods
Used to get components of object
Getter methods
size(), addElement()
Write Methods
Used to change components of object
Setter methods
addElement(), deleteElement(), replaceElement()
Distinction independent of Conventions

15. Vectors (java.util.Vector)
Vector v;
Vector Instance
null
James Dean
Object
Joe Doe
ALoan
Instance
Vector
Instance
v = new Vector();
v.addElement(“James Dean”)
v.addElement(“Joe Doe”)
v.addElement(5)
v.addElement(new ALoan())
v.addElement(new Vector())

16. Methods of Class Vector
public final int size()
public final Object elementAt(int index)
public final void addElement(Object obj)
public final void setElementAt(Object obj, int index)
public final void insertElementAt(Object obj, int index)
public final boolean removeElement(Object obj)
public final void removeElementAt(int index)
public final int indexOf(Object obj)
public final Enumeration elements()

17. Methods of Interface Enumeration (java.util.Enumeration)
public boolean hasMoreElements();
public Object nextElement();
Enumeration elements = vector.elements();
while ( elements.hasMoreElements())
System.out.println(elements.nextElement();

18. Methods of Interface Enumeration (java.util.Enumeration)
public boolean hasMoreElements();
public Object nextElement();
for (Enumeration elements = vector.elements();
elements.hasMoreElements();)
System.out.println(elements.nextElement();

19. Using Vector Directly as Point History
Point history user
Vector v = new Vector();
Vector Instance
null
size():  int
elementAt():
index  Object
PointModel
Instance
Violating Least Privilege
PointModel
Instance
addElement():
Object  void
Vector
Instance
removeElementAt():
Object  void
v.addElement(new APointModel(0,0);
v.addElement(new APointModel(10,90);
v.addElement(new Vector());
v.removeElementAt(0);

20. Encapsulating Vector in APointHistory
Point history user
PointHistory pointHistory = new APointHistory();
APointHistory instance
elementAt():
index  PointModel
addElement():
int*int  void
size():  int
Vector v = new Vector();
Vector Instance
null
size():  int
elementAt():
index  Object
PointModel
Instance
addElement():
Object  void
removeElementAt():
Object  void
pointHistory.addElement(0,0);
pointHistory.addElement(new Vector())

21. APointHistory Implementation
import java.util.Vector;
public class APointHistory implements PointHistory {
Vector contents = new Vector();
public void addElement (int x, int y) {
contents.addElement(new PointModel(x, y)); }
public PointModel elementAt (int index) {
return (PointModel) contents.elementAt(index);
public int size() {
return contents.size();

22. Animation
Animating point

23. Creating Animating Point
static final int ANIMATING_POINT_X = 0,
ANIMATING_POINT_Y = 0;
PointModel animatingPoint = new PointModel
(ANIMATING_POINT_X, ANIMATING_POINT_Y);
public PointModel getAnimatingPoint() {
return animatingPoint; }

24. Animating the Point public void animate () {
Enumeration points = contents.elements();
while (points.hasMoreElements()) {
animatingPoint.setCenter( ((PointModel) points.nextElement()).getCenter()); }
animatingPoint.setX(ANIMATING_POINT_X);
animatingPoint.setY(ANIMATING_POINT_Y);

25. Animating the Point public synchronized void animate () {
Enumeration points = contents.elements();
while (points.hasMoreElements()) {
animatingPoint.setCenter( ((PointModel) points.nextElement()).getCenter());
try {
Thread.sleep(ANIMATION_DELAY);
} catch (InterruptedException e) { System.out.println("Animation interrupted"); }
animatingPoint.setX(ANIMATING_POINT_X);
animatingPoint.setY(ANIMATING_POINT_Y);