// Purpose.?Rubber-band drawing demo (less-than-OO, brute force design)

import java.awt.*;
import java.awt.event.*;

public class RubberBandBrute extends  ?Canvas
implements MouseListener, MouseMotionListener {
abstract class Element {                                            ?//3
    ?protected int xo, yo;
    ?public abstract void draw( Graphics g );
}

class Line extends Element {
    ?private int xe, ye;
    ?public Line( int a, int b, int x, int y ) {
xo = a; yo = b; xe = x; ye = y;
    ?}
    ?public void draw( Graphics g ) {
g.drawLine( xo, yo, xe, ye );
}? }

class Rectangle extends Element {
    ?protected int w, h;
    ?public Rectangle( int x, int y, int ww, int hh ) {
xo = x; yo = y; w = ww; h = hh;
    ?}
    ?public void draw( Graphics g ) {
g.drawRect( xo, yo, w, h );
}? }

class Circle extends Rectangle {
    ?public Circle( int x, int y, int ww, int hh )? {
super( x, y, ww, hh );
    ?}
    ?public void draw( Graphics g ) {
g.drawOval( xo, yo, w, h );
}? }

private int x1, y1, x2, y2, total = 0;
private Element[] drawingList = new Element[30];                    ? //2
private int currentState;
private final int LINE = 1, RECT = 2, CIRC = 3;

public RubberBandBrute() {
    ?Frame f = new Frame( "RubberBandBrute" );
    ?f.add( this );? f.setSize( 300, 300 );? f.setVisible( true );
    ? addMouseListener( this );
    ? addMouseMotionListener( this );
}

public void mouseEntered( MouseEvent e ) { }
public void mouseExited(? MouseEvent e ) { }
public void mouseClicked( MouseEvent e ) { }
public void mousePressed( MouseEvent e ) {
    ?if ((e.getModifiers() & InputEvent.CTRL_MASK) == InputEvent.CTRL_MASK)
currentState = CIRC;                                          ?//4
    ?else if ((e.getModifiers() & InputEvent.BUTTON3_MASK)
                              ?== InputEvent.BUTTON3_MASK)
currentState = RECT;                                          ? //4
    ?else
currentState = LINE;                                          ? //4
    ?x1 = x2 = e.getX();
    ?y1 = y2 = e.getY();
}
public void mouseReleased( MouseEvent e ) {
    ?if (currentState == LINE)                                        ? //6
drawingList[total++] = new Line( x1, y1, e.getX(), e.getY() );
    ?else if (currentState == RECT)
drawingList[total++] =
          ?new Rectangle( Math.min(x1,e.getX()), Math.min(y1,e.getY()),
Math.abs(e.getX()-x1), Math.abs(e.getY()-y1) );
    ? else
drawingList[total++] =
          ? new Circle( Math.min(x1,e.getX()), Math.min(y1,e.getY()),
                      ?Math.abs(e.getX()-x1), Math.abs(e.getY()-y1) );
}

public void mouseMoved(MouseEvent e) { } // MouseMotionListener: btn up
public void mouseDragged(MouseEvent e) { // MouseMotionListener: btn down
    ?Graphics g = getGraphics();
    ?g.setXORMode( getBackground() ); //1
    ?if (currentState == LINE)          ?// undraw previous position //5
g.drawLine( x1, y1, x2, y2 );
    ?else if (currentState == RECT)
g.drawRect( Math.min(x1,x2), Math.min(y1,y2),
Math.abs(x2-x1), Math.abs(y2-y1) );
    ?else
g.drawOval( Math.min(x1,x2), Math.min(y1,y2),
Math.abs(x2-x1), Math.abs(y2-y1) );
    ?x2 = e.getX();
    ?y2 = e.getY();
    ?if (currentState == LINE)   ?/span>// draw current position
g.drawLine( x1, y1, x2, y2 );
    ?else if (currentState == RECT)
g.drawRect( Math.min(x1,x2), Math.min(y1,y2),
Math.abs(x2-x1), Math.abs(y2-y1) );
    ?else
g.drawOval( Math.min(x1,x2), Math.min(y1,y2),
Math.abs(x2-x1), Math.abs(y2-y1) );
    ? g.dispose();
}

public void paint( Graphics g ) {
    ?for (int i=0; i < total; i++) drawingList[i].draw( g );
}
public static void main( String[] args ) {
    ?new RubberBandBrute();
}?}



// Purpose.?OO rubber-band design (no: case stmt, state attribute, protected)

import java.awt.*;
import java.awt.event.*;

public class RubberBandBetter extends  ?Canvas
                            ?implements MouseListener, MouseMotionListener {
abstract class Element {
    ?private int xo, yo, xe, ye; //12
    ?public Element( int x, int y ) {
xo = xe = x; yo = ye = y;
    ?}
    ?// move() is the TEMPLATE METHOD, drawDerived() is the placeholder
    ?public void move( int x, int y ) { //8
Graphics g = getGraphics();
g.setXORMode( getBackground() );
drawDerived( g, xo, yo, xe, ye ); // undraw previous artifact
xe = x;?ye = y;
drawDerived( g, xo, yo, xe, ye ); // draw current artifact
g.dispose();
    ?}
    ?public void draw( Graphics g ) {                                ?//11
drawDerived( g, xo, yo, xe, ye );
    ?}
    ?public abstract void drawDerived( Graphics g, int a, int b, int x, int y);
}

class Line extends Element {
    ?public Line( int x, int y ) { super( x, y ); }
    ?public void drawDerived( Graphics g, int a, int b, int x, int y ) {
g.drawLine( a, b, x, y );
}? }

class Rectangle extends Element {
    ?public Rectangle( int x, int y ) { super( x, y ); }
    ?public void drawDerived( Graphics g, int a, int b, int x, int y ) {
g.drawRect( Math.min(a,x), Math.min(b,y),                    ?//14
Math.abs(x-a), Math.abs(y-b) );                  ?//13
}? }

class Circle extends Element {
    ?public Circle( int x, int y ) { super( x, y ); }
    ?public void drawDerived( Graphics g, int a, int b, int x, int y ) {
g.drawOval( Math.min(a,x), Math.min(b,y),                    ?//14
Math.abs(x-a), Math.abs(y-b) );                  ?//13
}? }

// STATE design pattern - the last ele of drawingList is the current STATE
private Element[] drawingList = new Element[30];
private int total = 0;

public RubberBandBetter() {
    ?Frame f = new Frame( "RubberBandBetter" );
    ? f.add( this );?f.setSize( 300, 300 );?f.setVisible( true );
    ?addMouseListener( this );
    ?addMouseMotionListener( this );
}

public void mouseEntered(? MouseEvent e ) { }
public void mouseExited( MouseEvent e ) { }
public void mouseClicked(?MouseEvent e ) { }

// STATE design pattern - case statement gone
public void mouseReleased( MouseEvent e ) { }                      ? //10

public void mousePressed(?MouseEvent e ) {
    ?if ((e.getModifiers() & InputEvent.CTRL_MASK) == InputEvent.CTRL_MASK)
drawingList[total++] = new Circle( e.getX(), e.getY() );      ?//9
    ?else if ((e.getModifiers() & InputEvent.BUTTON3_MASK)
                              ?== InputEvent.BUTTON3_MASK)
drawingList[total++] = new Rectangle( e.getX(), e.getY() ); //9
    ?else
drawingList[total++] = new Line( e.getX(), e.getY() );        ?//9
}

public void mouseMoved(MouseEvent e) { } // MouseMotionListener: btn up

// STATE design pattern - case statement gone
public void mouseDragged(MouseEvent e) { // MouseMotionListener: btn down
    ? drawingList[total-1].move( e.getX(), e.getY() ); //7
}

public void paint( Graphics g ) {
    ?for (int i=0; i < total; i++) drawingList[i].draw( g );
}
public static void main( String[] args ) {
    ?new RubberBandBetter();
}?}