Memento Pattern 2
//[C] 2002 Sun Microsystems, Inc.---
import java.io.Serializable;
import java.util.ArrayList;
public class RunMementoPattern {
public static void main(String[] arguments) {
System.out.println("Example for the Memento pattern");
System.out.println();
System.out
.println("This example will use the AddressBook to demonstrate");
System.out
.println(" how a Memento can be used to save and restore state.");
System.out
.println("The AddressBook has an inner class, AddressBookMemento,");
System.out
.println(" that is used to store the AddressBook state... in this");
System.out.println(" case, its internal list of contacts.");
System.out.println();
System.out.println("Creating the AddressBook");
AddressBook book = new AddressBook();
System.out.println("Adding Contact entries for the AddressBook");
book.addContact(new ContactImpl("Peter", "Taggart", "Commander",
"NSEA Protector", new AddressImpl()));
book.addContact(new ContactImpl("Tawny", "Madison", "Lieutenant",
"NSEA Protector", new AddressImpl()));
book.addContact(new ContactImpl("Dr.", "Lazarus", "Dr.",
"NSEA Protector", new AddressImpl()));
book.addContact(new ContactImpl("Tech Sargent", "Chen", "Tech Sargent",
"NSEA Protector", new AddressImpl()));
System.out.println("Contacts added. Current Contact list:");
System.out.println(book);
System.out.println();
System.out.println("Creating a Memento for the address book");
Object memento = book.getMemento();
System.out
.println("Now that a Memento exists, it can be used to restore");
System.out
.println(" the state of this AddressBook object, or to set the");
System.out.println(" state of a new AddressBook.");
System.out.println();
System.out.println("Creating new entries for the AddressBook");
book.removeAllContacts();
book.addContact(new ContactImpl("Jason", "Nesmith", "",
"Actor's Guild", new AddressImpl()));
book.addContact(new ContactImpl("Gwen", "DeMarco", "", "Actor's Guild",
new AddressImpl()));
book.addContact(new ContactImpl("Alexander", "Dane", "",
"Actor's Guild", new AddressImpl()));
book.addContact(new ContactImpl("Fred", "Kwan", "", "Actor's Guild",
new AddressImpl()));
System.out.println("New Contacts added. Current Contact list:");
System.out.println(book);
System.out.println();
System.out
.println("Using the Memento object to restore the AddressBook");
System.out.println(" to its original state.");
book.setMemento(memento);
System.out.println("AddressBook restored. Current Contact list:");
System.out.println(book);
}
}
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);
}
interface Address extends Serializable {
public static final String EOL_STRING = System
.getProperty("line.separator");
public static final String SPACE = " ";
public static final String COMMA = ",";
public String getType();
public String getDescription();
public String getStreet();
public String getCity();
public String getState();
public String getZipCode();
public void setType(String newType);
public void setDescription(String newDescription);
public void setStreet(String newStreet);
public void setCity(String newCity);
public void setState(String newState);
public void setZipCode(String newZip);
}
class ContactImpl implements Contact {
private String firstName;
private String lastName;
private String title;
private String organization;
private Address address;
public ContactImpl() {
}
public ContactImpl(String newFirstName, String newLastName,
String newTitle, String newOrganization, Address newAddress) {
firstName = newFirstName;
lastName = newLastName;
title = newTitle;
organization = newOrganization;
address = newAddress;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
public String getTitle() {
return title;
}
public String getOrganization() {
return organization;
}
public Address getAddress() {
return address;
}
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 void setAddress(Address newAddress) {
address = newAddress;
}
public String toString() {
return firstName + " " + lastName;
}
}
class AddressImpl implements Address {
private String type;
private String description;
private String street;
private String city;
private String state;
private String zipCode;
public AddressImpl() {
}
public AddressImpl(String newDescription, String newStreet, String newCity,
String newState, String newZipCode) {
description = newDescription;
street = newStreet;
city = newCity;
state = newState;
zipCode = newZipCode;
}
public String getType() {
return type;
}
public String getDescription() {
return description;
}
public String getStreet() {
return street;
}
public String getCity() {
return city;
}
public String getState() {
return state;
}
public String getZipCode() {
return zipCode;
}
public void setType(String newType) {
type = newType;
}
public void setDescription(String newDescription) {
description = newDescription;
}
public void setStreet(String newStreet) {
street = newStreet;
}
public void setCity(String newCity) {
city = newCity;
}
public void setState(String newState) {
state = newState;
}
public void setZipCode(String newZip) {
zipCode = newZip;
}
public String toString() {
return street + EOL_STRING + city + COMMA + SPACE + state + SPACE
+ zipCode + EOL_STRING;
}
}
class AddressBook {
private ArrayList contacts = new ArrayList();
public Object getMemento() {
return new AddressBookMemento(contacts);
}
public void setMemento(Object object) {
if (object instanceof AddressBookMemento) {
AddressBookMemento memento = (AddressBookMemento) object;
contacts = memento.state;
}
}
private class AddressBookMemento {
private ArrayList state;
private AddressBookMemento(ArrayList contacts) {
this.state = contacts;
}
}
public AddressBook() {
}
public AddressBook(ArrayList newContacts) {
contacts = newContacts;
}
public void addContact(Contact contact) {
if (!contacts.contains(contact)) {
contacts.add(contact);
}
}
public void removeContact(Contact contact) {
contacts.remove(contact);
}
public void removeAllContacts() {
contacts = new ArrayList();
}
public ArrayList getContacts() {
return contacts;
}
public String toString() {
return contacts.toString();
}
}
Related examples in the same category
