Java/Design Pattern/Factory Pattern
Содержание
Abstract Factory Pattern- Example
<source lang="java">
/* Software Architecture Design Patterns in Java by Partha Kuchana Auerbach Publications
- /
import java.awt.BorderLayout; import java.awt.Container; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JButton; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.SwingUtilities; import javax.swing.UIManager; import com.sun.java.swing.plaf.windows.WindowsLookAndFeel; public class AutoSearchUI extends JFrame {
public static final String newline = "\n";
public static final String SEARCH = "Search";
public static final String EXIT = "Exit";
public static final String CAR = "Car";
public static final String SUV = "SUV";
private JComboBox cmbVehicleCategory, cmbVehicleType;
private JLabel lblVehicleCategory, lblVehicleType, lblCarName,
lblCarNameValue;
public AutoSearchUI() {
super("Abstract Factory - Example");
cmbVehicleCategory = new JComboBox();
cmbVehicleCategory.addItem(VehicleFactory.LUXURY_VEHICLE);
cmbVehicleCategory.addItem(VehicleFactory.NON_LUXURY_VEHICLE);
cmbVehicleType = new JComboBox();
cmbVehicleType.addItem(AutoSearchUI.CAR);
cmbVehicleType.addItem(AutoSearchUI.SUV);
lblVehicleCategory = new JLabel("Vehicle Category:");
lblVehicleType = new JLabel("VehicleType:");
lblCarName = new JLabel("Search Result:");
lblCarNameValue = new JLabel(" Please click on Search button");
//Create the open button
JButton openButton = new JButton(AutoSearchUI.SEARCH);
openButton.setMnemonic(KeyEvent.VK_S);
JButton exitButton = new JButton(AutoSearchUI.EXIT);
exitButton.setMnemonic(KeyEvent.VK_X);
ButtonHandler objButtonHandler = new ButtonHandler(this);
openButton.addActionListener(objButtonHandler);
exitButton.addActionListener(new ButtonHandler());
JPanel buttonPanel = new JPanel();
//****************************************************
GridBagLayout gridbag = new GridBagLayout();
buttonPanel.setLayout(gridbag);
GridBagConstraints gbc = new GridBagConstraints();
buttonPanel.add(lblVehicleCategory);
buttonPanel.add(cmbVehicleCategory);
buttonPanel.add(lblVehicleType);
buttonPanel.add(cmbVehicleType);
buttonPanel.add(lblCarName);
buttonPanel.add(lblCarNameValue);
buttonPanel.add(openButton);
buttonPanel.add(exitButton);
gbc.insets.top = 5;
gbc.insets.bottom = 5;
gbc.insets.left = 5;
gbc.insets.right = 5;
gbc.anchor = GridBagConstraints.EAST;
gbc.gridx = 0;
gbc.gridy = 0;
gridbag.setConstraints(lblVehicleCategory, gbc);
gbc.anchor = GridBagConstraints.WEST;
gbc.gridx = 1;
gbc.gridy = 0;
gridbag.setConstraints(cmbVehicleCategory, gbc);
gbc.anchor = GridBagConstraints.EAST;
gbc.gridx = 0;
gbc.gridy = 1;
gridbag.setConstraints(lblVehicleType, gbc);
gbc.anchor = GridBagConstraints.WEST;
gbc.gridx = 1;
gbc.gridy = 1;
gridbag.setConstraints(cmbVehicleType, gbc);
gbc.anchor = GridBagConstraints.EAST;
gbc.gridx = 0;
gbc.gridy = 2;
gridbag.setConstraints(lblCarName, gbc);
gbc.anchor = GridBagConstraints.WEST;
gbc.gridx = 1;
gbc.gridy = 2;
gridbag.setConstraints(lblCarNameValue, gbc);
gbc.insets.left = 2;
gbc.insets.right = 2;
gbc.insets.top = 40;
gbc.anchor = GridBagConstraints.EAST;
gbc.gridx = 0;
gbc.gridy = 5;
gridbag.setConstraints(openButton, gbc);
gbc.anchor = GridBagConstraints.WEST;
gbc.gridx = 1;
gbc.gridy = 5;
gridbag.setConstraints(exitButton, gbc);
//****************************************************
//Add the buttons and the log to the frame
Container contentPane = getContentPane();
contentPane.add(buttonPanel, BorderLayout.CENTER);
try {
UIManager.setLookAndFeel(new WindowsLookAndFeel());
SwingUtilities.updateComponentTreeUI(AutoSearchUI.this);
} catch (Exception ex) {
System.out.println(ex);
}
}
public static void main(String[] args) {
JFrame frame = new AutoSearchUI();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//frame.pack();
frame.setSize(400, 300);
frame.setVisible(true);
}
public String getSelectedCategory() {
return (String) cmbVehicleCategory.getSelectedItem();
}
public String getSelectedType() {
return (String) cmbVehicleType.getSelectedItem();
}
public void setResult(String searchResult) {
lblCarNameValue.setText(searchResult);
}
} // End of class AutoSearchUI class ButtonHandler implements ActionListener {
AutoSearchUI objAutoSearchUI;
public void actionPerformed(ActionEvent e) {
String searchResult = null;
if (e.getActionCommand().equals(AutoSearchUI.EXIT)) {
System.exit(1);
}
if (e.getActionCommand().equals(AutoSearchUI.SEARCH)) {
//get input values
String vhCategory = objAutoSearchUI.getSelectedCategory();
String vhType = objAutoSearchUI.getSelectedType();
//get one of Luxury or NonLuxury vehicle factories
VehicleFactory vf = VehicleFactory.getVehicleFactory(vhCategory);
if (vhType.equals(AutoSearchUI.CAR)) {
Car c = vf.getCar();
searchResult = "Name: " + c.getCarName() + " Features: "
+ c.getCarFeatures();
}
if (vhType.equals(AutoSearchUI.SUV)) {
SUV s = vf.getSUV();
searchResult = "Name: " + s.getSUVName() + " Features: "
+ s.getSUVFeatures();
}
objAutoSearchUI.setResult(searchResult);
}
}
public ButtonHandler() {
}
public ButtonHandler(AutoSearchUI inObjAutoSearchUI) {
objAutoSearchUI = inObjAutoSearchUI;
}
} // End of class ButtonHandler abstract class VehicleFactory {
public static final String LUXURY_VEHICLE = "Luxury";
public static final String NON_LUXURY_VEHICLE = "Non-Luxury";
public abstract Car getCar();
public abstract SUV getSUV();
public static VehicleFactory getVehicleFactory(String type) {
if (type.equals(VehicleFactory.LUXURY_VEHICLE))
return new LuxuryVehicleFactory();
if (type.equals(VehicleFactory.NON_LUXURY_VEHICLE))
return new NonLuxuryVehicleFactory();
return new LuxuryVehicleFactory();
}
} // End of class interface Car {
public String getCarName(); public String getCarFeatures();
} // End of class interface SUV {
public String getSUVName(); public String getSUVFeatures();
} // End of class class LuxuryCar implements Car {
private String name;
public LuxuryCar(String cName) {
name = cName;
}
public String getCarName() {
return name;
}
public String getCarFeatures() {
return "Luxury Car Features ";
};
} // End of class class LuxurySUV implements SUV {
private String name;
public LuxurySUV(String sName) {
name = sName;
}
public String getSUVName() {
return name;
}
public String getSUVFeatures() {
return "Luxury SUV Features ";
};
} // End of class class LuxuryVehicleFactory extends VehicleFactory {
public Car getCar() {
return new LuxuryCar("L-C");
}
public SUV getSUV() {
return new LuxurySUV("L-S");
}
} // End of class class NonLuxuryCar implements Car {
private String name;
public NonLuxuryCar(String cName) {
name = cName;
}
public String getCarName() {
return name;
}
public String getCarFeatures() {
return "Non-Luxury Car Features ";
};
} // End of class class NonLuxurySUV implements SUV {
private String name;
public NonLuxurySUV(String sName) {
name = sName;
}
public String getSUVName() {
return name;
}
public String getSUVFeatures() {
return "Non-Luxury SUV Features ";
};
} // End of class class NonLuxuryVehicleFactory extends VehicleFactory {
public Car getCar() {
return new NonLuxuryCar("NL-C");
}
public SUV getSUV() {
return new NonLuxurySUV("NL-S");
}
} // End of class
</source>
Abstract Factory Pattern in Java 2
<source lang="java">
//[C] 2002 Sun Microsystems, Inc.--- public class RunAbstractFactoryPattern {
public static void main(String [] arguments){
System.out.println("Example for the AbstractFactory pattern");
System.out.println();
System.out.println(" (take a look in the RunPattern code. Notice that you can");
System.out.println(" use the Address and PhoneNumber classes when writing");
System.out.println(" almost all of the code. This allows you to write a very");
System.out.println(" generic framework, and plug in Concrete Factories");
System.out.println(" and Products to specialize the behavior of your code)");
System.out.println();
System.out.println("Creating U.S. Address and Phone Number:");
AddressFactory usAddressFactory = new USAddressFactory();
Address usAddress = usAddressFactory.createAddress();
PhoneNumber usPhone = usAddressFactory.createPhoneNumber();
usAddress.setStreet("142 Lois Lane");
usAddress.setCity("Metropolis");
usAddress.setRegion("WY");
usAddress.setPostalCode("54321");
usPhone.setPhoneNumber("7039214722");
System.out.println("U.S. address:");
System.out.println(usAddress.getFullAddress());
System.out.println("U.S. phone number:");
System.out.println(usPhone.getPhoneNumber());
System.out.println();
System.out.println();
System.out.println("Creating French Address and Phone Number:");
AddressFactory frenchAddressFactory = new FrenchAddressFactory();
Address frenchAddress = frenchAddressFactory.createAddress();
PhoneNumber frenchPhone = frenchAddressFactory.createPhoneNumber();
frenchAddress.setStreet("21 Rue Victor Hugo");
frenchAddress.setCity("Courbevoie");
frenchAddress.setPostalCode("40792");
frenchPhone.setPhoneNumber("011324290");
System.out.println("French address:");
System.out.println(frenchAddress.getFullAddress());
System.out.println("French phone number:");
System.out.println(frenchPhone.getPhoneNumber());
}
} class FrenchAddressFactory implements AddressFactory{
public Address createAddress(){
return new FrenchAddress();
}
public PhoneNumber createPhoneNumber(){
return new FrenchPhoneNumber();
}
} class USAddressFactory implements AddressFactory{
public Address createAddress(){
return new USAddress();
}
public PhoneNumber createPhoneNumber(){
return new USPhoneNumber();
}
} class USPhoneNumber extends PhoneNumber{
private static final String COUNTRY_CODE = "01";
private static final int NUMBER_LENGTH = 10;
public String getCountryCode(){ return COUNTRY_CODE; }
public void setPhoneNumber(String newNumber){
if (newNumber.length() == NUMBER_LENGTH){
super.setPhoneNumber(newNumber);
}
}
} interface AddressFactory{
public Address createAddress(); public PhoneNumber createPhoneNumber();
} abstract class Address{
private String street;
private String city;
private String region;
private String postalCode;
public static final String EOL_STRING =
System.getProperty("line.separator");
public static final String SPACE = " ";
public String getStreet(){ return street; }
public String getCity(){ return city; }
public String getPostalCode(){ return postalCode; }
public String getRegion(){ return region; }
public abstract String getCountry();
public String getFullAddress(){
return street + EOL_STRING +
city + SPACE + postalCode + EOL_STRING;
}
public void setStreet(String newStreet){ street = newStreet; }
public void setCity(String newCity){ city = newCity; }
public void setRegion(String newRegion){ region = newRegion; }
public void setPostalCode(String newPostalCode){ postalCode = newPostalCode; }
} abstract class PhoneNumber{
private String phoneNumber;
public abstract String getCountryCode();
public String getPhoneNumber(){ return phoneNumber; }
public void setPhoneNumber(String newNumber){
try{
Long.parseLong(newNumber);
phoneNumber = newNumber;
}
catch (NumberFormatException exc){
}
}
}
class FrenchPhoneNumber extends PhoneNumber{
private static final String COUNTRY_CODE = "33";
private static final int NUMBER_LENGTH = 9;
public String getCountryCode(){ return COUNTRY_CODE; }
public void setPhoneNumber(String newNumber){
if (newNumber.length() == NUMBER_LENGTH){
super.setPhoneNumber(newNumber);
}
}
} class FrenchAddress extends Address{
private static final String COUNTRY = "FRANCE";
public String getCountry(){ return COUNTRY; }
public String getFullAddress(){
return getStreet() + EOL_STRING +
getPostalCode() + SPACE + getCity() +
EOL_STRING + COUNTRY + EOL_STRING;
}
} class USAddress extends Address{
private static final String COUNTRY = "UNITED STATES";
private static final String COMMA = ",";
public String getCountry(){ return COUNTRY; }
public String getFullAddress(){
return getStreet() + EOL_STRING +
getCity() + COMMA + SPACE + getRegion() +
SPACE + getPostalCode() + EOL_STRING +
COUNTRY + EOL_STRING;
}
}
</source>
Factory Method Pattern in Java
<source lang="java">
//[C] 2002 Sun Microsystems, Inc.--- import java.awt.Container; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.io.Serializable; import javax.swing.BoxLayout; import javax.swing.JButton; import javax.swing.JComponent; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.JTextField;
public class RunFactoryMethodPattern {
public static void main(String [] arguments){
System.out.println("Example for the FactoryMethod pattern");
System.out.println();
System.out.println("Creating a Contact object");
System.out.println();
Contact someone = new Contact();
System.out.println("Creating a GUI editor for the Contact");
System.out.println();
System.out.println("The GUI defined in the EditorGui class is a truly generic editor.");
System.out.println("It accepts an argument of type ItemEditor, and delegates");
System.out.println(" all editing tasks to its ItemEditor and the associated GUI.");
System.out.println(" The getEditor() Factory Method is used to obtain the ItemEditor");
System.out.println(" for the example.");
System.out.println();
System.out.println("Notice that the editor in the top portion of the GUI is,");
System.out.println(" in fact, returned by the ItemEditor belonging to the");
System.out.println(" Contact class, and has appropriate fields for that class.");
EditorGui runner = new EditorGui(someone.getEditor());
runner.createGui();
}
} class EditorGui implements ActionListener{
private JFrame mainFrame;
private JTextArea display;
private JButton update, exit;
private JPanel controlPanel, displayPanel, editorPanel;
private ItemEditor editor;
public EditorGui(ItemEditor edit){
editor = edit;
}
public void createGui(){
mainFrame = new JFrame("Factory Pattern Example");
Container content = mainFrame.getContentPane();
content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
editorPanel = new JPanel();
editorPanel.add(editor.getGUI());
content.add(editorPanel);
displayPanel = new JPanel();
display = new JTextArea(10, 40);
display.setEditable(false);
displayPanel.add(display);
content.add(displayPanel);
controlPanel = new JPanel();
update = new JButton("Update Item");
exit = new JButton("Exit");
controlPanel.add(update);
controlPanel.add(exit);
content.add(controlPanel);
update.addActionListener(this);
exit.addActionListener(this);
mainFrame.addWindowListener(new WindowCloseManager());
mainFrame.pack();
mainFrame.setVisible(true);
}
public void actionPerformed(ActionEvent evt){
Object originator = evt.getSource();
if (originator == update){
updateItem();
}
else if (originator == exit){
exitApplication();
}
}
private class WindowCloseManager extends WindowAdapter{
public void windowClosing(WindowEvent evt){
exitApplication();
}
}
private void updateItem(){
editor.rumitChanges();
display.setText(editor.toString());
}
private void exitApplication(){
System.exit(0);
}
} class Contact implements Editable, Serializable {
private String name;
private String relationship;
public ItemEditor getEditor() {
return new ContactEditor();
}
private class ContactEditor implements ItemEditor, Serializable {
private transient JPanel panel;
private transient JTextField nameField;
private transient JTextField relationField;
public JComponent getGUI() {
if (panel == null) {
panel = new JPanel();
nameField = new JTextField(name);
relationField = new JTextField(relationship);
panel.setLayout(new GridLayout(2,2));
panel.add(new JLabel("Name:"));
panel.add(nameField);
panel.add(new JLabel("Relationship:"));
panel.add(relationField);
} else {
nameField.setText(name);
relationField.setText(relationship);
}
return panel;
}
public void commitChanges() {
if (panel != null) {
name = nameField.getText();
relationship = relationField.getText();
}
}
public String toString(){
return "\nContact:\n" +
" Name: " + name + "\n" +
" Relationship: " + relationship;
}
}
} interface Editable {
public ItemEditor getEditor();
} interface ItemEditor {
public JComponent getGUI(); public void commitChanges();
}
</source>
Fly weight Factory
<source lang="java">
/* Software Architecture Design Patterns in Java by Partha Kuchana Auerbach Publications
- /
import java.util.HashMap; import java.util.StringTokenizer; import java.util.Vector; public class FlyweightTest {
public static void main(String[] args) throws Exception {
Vector empList = initialize();
FlyweightFactory factory = FlyweightFactory.getInstance();
for (int i = 0; i < empList.size(); i++) {
String s = (String) empList.elementAt(i);
StringTokenizer st = new StringTokenizer(s, ",");
String name = st.nextToken();
String title = st.nextToken();
String division = st.nextToken();
FlyweightIntr flyweight = factory.getFlyweight(division);
//associate the flyweight
//with the extrinsic data object.
VCard card = new VCard(name, title, flyweight);
card.print();
}
}
private static Vector initialize() {
//for simplicity values are being hardcoded.
Vector v = new Vector();
v.add("name1,title1,North");
v.add("name2,title2,South");
v.add("name3,title1,North");
v.add("name4,title3,East");
v.add("name5,title4,East");
v.add("name6,title2,East");
v.add("name7,title1,West");
v.add("name8,title3,West");
v.add("name9,title1,West");
v.add("name10,title6,South");
v.add("name11,title5,North");
v.add("name12,title1,North");
return v;
}
} class FlyweightFactory {
private HashMap lstFlyweight;
private static FlyweightFactory factory = new FlyweightFactory();
private FlyweightFactory() {
lstFlyweight = new HashMap();
}
public synchronized FlyweightIntr getFlyweight(String divisionName) {
if (lstFlyweight.get(divisionName) == null) {
FlyweightIntr fw = new Flyweight(divisionName);
lstFlyweight.put(divisionName, fw);
return fw;
} else {
return (FlyweightIntr) lstFlyweight.get(divisionName);
}
}
public static FlyweightFactory getInstance() {
return factory;
}
//Inner flyweight class
private class Flyweight implements FlyweightIntr {
private String company;
private String address;
private String city;
private String state;
private String zip;
private void setValues(String cmp, String addr, String cty, String st,
String zp) {
company = cmp;
address = addr;
city = cty;
state = st;
zip = zp;
}
private Flyweight(String division) {
// values are hard coded
//for simplicity
if (division.equals("North")) {
setValues("CMP", "addr1", "cty1", "st1", "10000");
}
if (division.equals("South")) {
setValues("CMP", "addr2", "cty2", "st2", "20000");
}
if (division.equals("East")) {
setValues("CMP", "addr3", "cty3", "st3", "30000");
}
if (division.equals("West")) {
setValues("CMP", "addr4", "cty4", "st4", "40000");
}
}
public String getCompany() {
return company;
}
public String getAddress() {
return address;
}
public String getCity() {
return city;
}
public String getState() {
return state;
}
public String getZip() {
return zip;
}
}// end of Flyweight
}// end of FlyweightFactory interface FlyweightIntr {
public String getCompany(); public String getAddress(); public String getCity(); public String getState(); public String getZip();
} class VCard {
String name;
String title;
FlyweightIntr objFW;
public VCard(String n, String t, FlyweightIntr fw) {
name = n;
title = t;
objFW = fw;
}
public void print() {
System.out.println(name);
System.out.println(title);
System.out.println(objFW.getAddress() + "-" + objFW.getCity() + "-"
+ objFW.getState() + "-" + objFW.getZip());
System.out.println("----------------");
}
}
</source>
Illustrates use of Abstract Factory pattern
<source lang="java">
/* 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");
}
}
</source>
