Mediator Pattern 2
//[C] 2002 Sun Microsystems, Inc.---
import java.awt.BorderLayout;
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 java.util.ArrayList;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class RunMediatorPattern {
public static void main(String [] arguments){
System.out.println("Example for the Mediator pattern");
System.out.println("In this demonstration, the ContactMediatorImpl class will");
System.out.println(" coordinate updates between three controls in a GUI - the");
System.out.println(" ContactDisplayPanel, the ContactEditorPanel, and the");
System.out.println(" ContactSelectorPanel. As its name suggests, the Mediator");
System.out.println(" mediates the activity between the elements of the GUI,");
System.out.println(" translating method calls from one panel into the appropriate");
System.out.println(" method calls on the other GUI components.");
Contact contact = new ContactImpl("", "", "", "");
Contact contact1 = new ContactImpl("Duke", "", "Java Advocate", "The Patterns Guild");
ContactMediatorImpl mediator = new ContactMediatorImpl();
mediator.addContact(contact);
mediator.addContact(contact1);
MediatorGui gui = new MediatorGui();
gui.setContactMediator(mediator);
gui.createGui();
}
}
class ContactEditorPanel extends JPanel implements ActionListener{
private ContactMediator mediator;
private JTextField firstName, lastName, title, organization;
private JButton create, update;
public ContactEditorPanel(){
createGui();
}
public ContactEditorPanel(ContactMediator newMediator){
setContactMediator(newMediator);
createGui();
}
public void createGui(){
setLayout(new BorderLayout());
JPanel editor = new JPanel();
editor.setLayout(new GridLayout(4, 2));
editor.add(new JLabel("First Name:"));
firstName = new JTextField(20);
editor.add(firstName);
editor.add(new JLabel("Last Name:"));
lastName = new JTextField(20);
editor.add(lastName);
editor.add(new JLabel("Title:"));
title = new JTextField(20);
editor.add(title);
editor.add(new JLabel("Organization:"));
organization = new JTextField(20);
editor.add(organization);
add(editor, BorderLayout.CENTER);
JPanel control = new JPanel();
create = new JButton("Create Contact");
update = new JButton("Update Contact");
create.addActionListener(this);
update.addActionListener(this);
control.add(create);
control.add(update);
add(control, BorderLayout.SOUTH);
}
public void actionPerformed(ActionEvent evt){
Object source = evt.getSource();
if (source == create){
createContact();
}
else if (source == update){
updateContact();
}
}
public void createContact(){
mediator.createContact(firstName.getText(), lastName.getText(),
title.getText(), organization.getText());
}
public void updateContact(){
mediator.updateContact(firstName.getText(), lastName.getText(),
title.getText(), organization.getText());
}
public void setContactFields(Contact contact){
firstName.setText(contact.getFirstName());
lastName.setText(contact.getLastName());
title.setText(contact.getTitle());
organization.setText(contact.getOrganization());
}
public void setContactMediator(ContactMediator newMediator){
mediator = newMediator;
}
}
class ContactMediatorImpl implements ContactMediator{
private ContactDisplayPanel display;
private ContactEditorPanel editor;
private ContactSelectorPanel selector;
private ArrayList contacts = new ArrayList();
private int contactIndex;
public void setContactDisplayPanel(ContactDisplayPanel displayPanel){
display = displayPanel;
}
public void setContactEditorPanel(ContactEditorPanel editorPanel){
editor = editorPanel;
}
public void setContactSelectorPanel(ContactSelectorPanel selectorPanel){
selector = selectorPanel;
}
public void createContact(String firstName, String lastName, String title, String organization){
Contact newContact = new ContactImpl(firstName, lastName, title, organization);
addContact(newContact);
selector.addContact(newContact);
display.contactChanged(newContact);
}
public void updateContact(String firstName, String lastName, String title, String organization){
Contact updateContact = (Contact)contacts.get(contactIndex);
if (updateContact != null){
updateContact.setFirstName(firstName);
updateContact.setLastName(lastName);
updateContact.setTitle(title);
updateContact.setOrganization(organization);
display.contactChanged(updateContact);
}
}
public void selectContact(Contact contact){
if (contacts.contains(contact)){
contactIndex = contacts.indexOf(contact);
display.contactChanged(contact);
editor.setContactFields(contact);
}
}
public Contact [] getAllContacts(){
return (Contact [])contacts.toArray(new Contact[1]);
}
public void addContact(Contact contact){
if (!contacts.contains(contact)){
contacts.add(contact);
}
}
}
class ContactDisplayPanel extends JPanel{
private ContactMediator mediator;
private JTextArea displayRegion;
public ContactDisplayPanel(){
createGui();
}
public ContactDisplayPanel(ContactMediator newMediator){
setContactMediator(newMediator);
createGui();
}
public void createGui(){
setLayout(new BorderLayout());
displayRegion = new JTextArea(10, 40);
displayRegion.setEditable(false);
add(new JScrollPane(displayRegion));
}
public void contactChanged(Contact contact){
displayRegion.setText(
"Contact\n\tName: " + contact.getFirstName() +
" " + contact.getLastName() + "\n\tTitle: " +
contact.getTitle() + "\n\tOrganization: " +
contact.getOrganization());
}
public void setContactMediator(ContactMediator newMediator){
mediator = newMediator;
}
}
class ContactSelectorPanel extends JPanel implements ActionListener{
private ContactMediator mediator;
private JComboBox selector;
public ContactSelectorPanel(){
createGui();
}
public ContactSelectorPanel(ContactMediator newMediator){
setContactMediator(newMediator);
createGui();
}
public void createGui(){
selector = new JComboBox(mediator.getAllContacts());
selector.addActionListener(this);
add(selector);
}
public void actionPerformed(ActionEvent evt){
mediator.selectContact((Contact)selector.getSelectedItem());
}
public void addContact(Contact contact){
selector.addItem(contact);
selector.setSelectedItem(contact);
}
public void setContactMediator(ContactMediator newMediator){
mediator = newMediator;
}
}
class MediatorGui{
private ContactMediator mediator;
public void setContactMediator(ContactMediator newMediator){ mediator = newMediator; }
public void createGui(){
JFrame mainFrame = new JFrame("Mediator example");
Container content = mainFrame.getContentPane();
content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS));
ContactSelectorPanel select = new ContactSelectorPanel(mediator);
ContactDisplayPanel display = new ContactDisplayPanel(mediator);
ContactEditorPanel edit = new ContactEditorPanel(mediator);
content.add(select);
content.add(display);
content.add(edit);
mediator.setContactSelectorPanel(select);
mediator.setContactDisplayPanel(display);
mediator.setContactEditorPanel(edit);
mainFrame.addWindowListener(new WindowCloseManager());
mainFrame.pack();
mainFrame.setVisible(true);
}
private class WindowCloseManager extends WindowAdapter{
public void windowClosing(WindowEvent evt){
System.exit(0);
}
}
}
interface ContactMediator{
public void setContactDisplayPanel(ContactDisplayPanel displayPanel);
public void setContactEditorPanel(ContactEditorPanel editorPanel);
public void setContactSelectorPanel(ContactSelectorPanel selectorPanel);
public void createContact(String firstName, String lastName, String title, String organization);
public void updateContact(String firstName, String lastName, String title, String organization);
public Contact [] getAllContacts();
public void selectContact(Contact contact);
}
interface Contact extends Serializable{
public static final String SPACE = " ";
public String getFirstName();
public String getLastName();
public String getTitle();
public String getOrganization();
public void setFirstName(String newFirstName);
public void setLastName(String newLastName);
public void setTitle(String newTitle);
public void setOrganization(String newOrganization);
}
class ContactImpl implements Contact{
private String firstName;
private String lastName;
private String title;
private String organization;
public ContactImpl(){}
public ContactImpl(String newFirstName, String newLastName,
String newTitle, String newOrganization){
firstName = newFirstName;
lastName = newLastName;
title = newTitle;
organization = newOrganization;
}
public String getFirstName(){ return firstName; }
public String getLastName(){ return lastName; }
public String getTitle(){ return title; }
public String getOrganization(){ return organization; }
public void setFirstName(String newFirstName){ firstName = newFirstName; }
public void setLastName(String newLastName){ lastName = newLastName; }
public void setTitle(String newTitle){ title = newTitle; }
public void setOrganization(String newOrganization){ organization = newOrganization; }
public String toString(){
return firstName + SPACE + lastName;
}
}
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