Windows

Supporting files:

Windows.java
Display.java
Manager.java
Window.java

Objectives:

To acquire some mastery with the use of arrays, particularly for representing a collection of elements.
To learn some basic concepts underlying graphical user interfaces.

Most graphical user interfaces are based on a stack of overlapping rectangles that we know as "windows." In this assignment, we'll create a class whose job is to manage the set of windows available in a simple simulation of an overall user interface.

In this user interface, the display is the gray area at the top of the application; the white text area below is a log of what has happened, to help with debugging.

When the application is working, you will be able to interact with windows in a variety of ways.

Create a new window by clicking on the gray background and dragging to determine the window's size.
Resize a window by clicking on the small triangle on the window's bottom left corner and dragging.
Bring a window on the top of all the rest by clicking it outside the resize triangle.
Move a window by clicking it outside the resize triangle and dragging. Note that this does not bring the window to the front, as many other windowing systems do.
Delete the most recently clicked window by pressing the Backspace or Delete key.
Display a list of all current windows in the log area by pressing the space bar or Enter key.

Distributed with this assignment are four classes. All are complete except the Manager class; you should not modify the other classes.

Window	Represents a single rectangular window.
Manager	Manages the current list of windows.
Display	Implements the display interface.
Windows	Provides the overall application.

Your assignment is to complete four crucial methods for managing the list of windows.

void add(Window toAdd): Adds toAdd to this window list so that it appears on top. Don't worry about what happens if the array is already full.
void remove(Window toRemove): Removes toRemove from this window list.
Window find(int x, int y): Returns the uppermost window in this list containing the point (x,y), or null if no windows contain the point. Note that this windowing system, like most, inverts the y-axis from what is conventionally used in mathematics: The y=0 line is at the display's top, and y increases as you move downward.
void paintAll(Graphics g): Paints all the windows in this list, starting with the lowermost. To paint an individual window, use its paint method (passing the g parameter to it). You don't need to use the parameter g in way other than to hand it to each individual window.

The Manager class contains a windows instance variable, which is an array of Window objects that you should use for storing the current list of windows. You should use the windowCount instance variable to remember how many windows there currently are. Whether your array lists windows from the bottom up or from the top down is up to you.

Your implementation will need to use the following methods from the Window class.

int getX(): Returns the x-coordinate of this window's left edge.
int getY(): Returns the y-coordinate of this window's top edge.
int getWidth(): Returns the width of this window, in pixels.
int getHeight(): Returns the height of this window, in pixels.
void paint(Graphics g): Paints this window using g.