Rectangle Class Diagram

Ancestor class specifications:

java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent

Rectangle Class Specification

Invariant

A Rectangle object...

- is drawn as a rectangular solid.

- should be added to a container object with its upper-left corner x pixels from the left and y pixels from the top. (The upper left corner of the container is (0, 0).)

- when it is contained within a proper GUI container the rectangle appears in color color and the dimensions of the rectangle are given by width and height.

- if necessary, the rectangle image is clipped to the boundaries of its GUI container.

Below is a black Rectangle added to My Window.

Constructor Methods

public Rectangle( int initX, int initY, int w, int h )

post: A new Rectangle object is created

and color == Color.black

and x == initX and y == initY

and width == w and height == h

(Note that Rectangles don't appear until added.)

Update Methods

public void setBackground( java.awt.Color c )

post: color == c

public void setLocation( int intX, int initY )

post: x == initX and y == initY

public void setSize( int w, int h )

post: width == w and height == h

public void repaint( )

post: Causes the Java virtual machine to update the display of this object as soon as possible.

public void add( java.awt.Component c, int j )

pre: j == 0 for best results

post: The pic graphical object will be drawn upon this Rectangle

Query Methods

public java.awt.Color getBackground( )

post: color == c

public int getX( )

post: result == x

public int getY( )

post: result == y

public int getWidth( )

post: result == width

public int getHeight( )

post: result == height

public java.awt.Container getParent( )

post: this Rectangle is added to a Container

implies result == the Container to which this is added

and this Rectangle is not added implies result == null