Mega Code Archive
Illustrates use of Abstract Factory pattern
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/*
The Design Patterns Java Companion
Copyright (C) 1998, by James W. Cooper
IBM Thomas J. Watson Research Center
*/
import java.awt.Button;
import java.awt.Checkbox;
import java.awt.CheckboxGroup;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
public class Gardener extends Frame implements ActionListener, ItemListener {
private Checkbox Vegie, Annual, Peren;
private Button Center, Border, Shade, Quit;
private Garden garden = null;
private GardenPanel gardenPlot;
private String borderPlant = "", centerPlant = "", shadePlant = "";
public Gardener() {
super("Garden planner");
setGUI();
}
//----------------------------------
private void setGUI() {
setBackground(Color.lightGray);
setLayout(new GridLayout(1, 2));
Panel left = new Panel();
add(left);
Panel right = new Panel();
add(right);
//create label and 3 radio buttons on left side
left.setLayout(new GridLayout(4, 1));
left.add(new Label("Garden type"));
CheckboxGroup grp = new CheckboxGroup();
Vegie = new Checkbox("Vegetable", grp, false);
Annual = new Checkbox("Annual", grp, false);
Peren = new Checkbox("Perennial", grp, false);
left.add(Vegie);
left.add(Annual);
left.add(Peren);
Vegie.addItemListener(this);
Peren.addItemListener(this);
Annual.addItemListener(this);
//now create right side
right.setLayout(new GridLayout(2, 1));
gardenPlot = new GardenPanel();
gardenPlot.setBackground(Color.white);
Panel botRight = new Panel();
right.add(gardenPlot);
right.add(botRight);
Center = new Button("Central");
Border = new Button("Border");
Shade = new Button("Shade");
Quit = new Button("Quit");
botRight.add(Center);
Center.addActionListener(this);
botRight.add(Border);
Border.addActionListener(this);
botRight.add(Shade);
Shade.addActionListener(this);
botRight.add(Quit);
Quit.addActionListener(this);
setBounds(200, 200, 400, 300);
setVisible(true);
}
//----------------------------------
public void actionPerformed(ActionEvent e) {
Object obj = e.getSource();
if (obj == Center)
setCenter();
if (obj == Border)
setBorder();
if (obj == Shade)
setShade();
if (obj == Quit)
System.exit(0);
}
//----------------------------------
private void setCenter() {
if (garden != null)
centerPlant = garden.getCenter().getName();
gardenPlot.repaint();
}
private void setBorder() {
if (garden != null)
borderPlant = garden.getBorder().getName();
gardenPlot.repaint();
}
private void setShade() {
if (garden != null)
shadePlant = garden.getShade().getName();
gardenPlot.repaint();
}
//----------------------------------
public void itemStateChanged(ItemEvent e) {
Checkbox ck = (Checkbox) e.getSource();
garden = new GardenMaker().getGarden(ck.getLabel());
shadePlant = "";
centerPlant = "";
borderPlant = "";
gardenPlot.repaint();
}
//----------------------------------
static public void main(String argv[]) {
new Gardener();
}
//--------------------------------
class GardenPanel extends Panel {
public void paint(Graphics g) {
Dimension sz = getSize();
g.setColor(Color.lightGray);
g.fillArc(0, 0, 80, 80, 0, 360);
g.setColor(Color.black);
g.drawRect(0, 0, sz.width - 1, sz.height - 1);
g.drawString(centerPlant, 100, 50);
g.drawString(borderPlant, 75, 120);
g.drawString(shadePlant, 10, 40);
}
}
} //end of Gardener class
//=============================================
class GardenMaker {
//Abstract Factory which returns one of three gardens
private Garden gd;
public Garden getGarden(String gtype) {
gd = new VegieGarden(); //default
if (gtype.equals("Perennial"))
gd = new PerennialGarden();
if (gtype.equals("Annual"))
gd = new AnnualGarden();
return gd;
}
}
abstract class Garden {
public abstract Plant getShade();
public abstract Plant getCenter();
public abstract Plant getBorder();
}
class Plant {
String name;
public Plant(String pname) {
name = pname; //save name
}
public String getName() {
return name;
}
}
class VegieGarden extends Garden {
public Plant getShade() {
return new Plant("Broccoli");
}
public Plant getCenter() {
return new Plant("Corn");
}
public Plant getBorder() {
return new Plant("Peas");
}
}
class AnnualGarden extends Garden {
public Plant getShade() {
return new Plant("Coleus");
}
public Plant getCenter() {
return new Plant("Marigold");
}
public Plant getBorder() {
return new Plant("Alyssum");
}
}
class PerennialGarden extends Garden
{
public Plant getShade()
{
return new Plant("Astilbe");
}
public Plant getCenter()
{
return new Plant("Dicentrum");
}
public Plant getBorder()
{
return new Plant("Sedum");
}
}
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