Senior Java Developer:
CODE:
public interface Subject {
public void attach(Observer observer);
public void detach(Observer observer);
public void notifyObservers();
}
public interface Observer {
public void update(Subject subject);
}
public class HelloWorldSubject implements Subject {
private List<Observer> observers;
private String str;
public HelloWorldSubject() {
super();
observers = new ArrayList<Observer>();
}
public void attach(Observer observer) {
observers.add(observer);
}
public void detach(Observer observer) {
observers.remove(observer);
}
public void notifyObservers() {
Iterator<Observer> iter = observers.iterator();
while (iter.hasNext()) {
Observer observer = iter.next();
observer.update(this);
}
}
public String getStr() {
return str;
}
public void setStr(String str) {
this.str = str;
notifyObservers();
}
}
public class HelloWorldObserver implements Observer {
public void update(Subject subject) {
HelloWorldSubject sub = (HelloWorldSubject)subject;
System.out.println(sub.getStr());
}
}
public interface Command {
void execute();
}
public class HelloWorldCommand implements Command {
private HelloWorldSubject subject;
public HelloWorldCommand(Subject subject) {
super();
this.subject = (HelloWorldSubject)subject;
}
public void execute() {
subject.setStr("hello world");
}
}
public interface AbstractFactory {
public Subject createSubject();
public Observer createObserver();
public Command createCommand(Subject subject);
}
public class HelloWorldFactory implements AbstractFactory {
public Subject createSubject() {
return new HelloWorldSubject();
}
public Observer createObserver() {
return new HelloWorldObserver();
}
public Command createCommand(Subject subject) {
return new HelloWorldCommand(subject);
}
}
public class FactoryMakerSingleton {
private static FactoryMakerSingleton instance = null;
private AbstractFactory factory;
private FactoryMakerSingleton() {
factory = new HelloWorldFactory();
}
public static synchronized FactoryMakerSingleton getInstance() {
if (instance == null) {
instance = new FactoryMakerSingleton();
}
return instance;
}
public AbstractFactory getFactory() {
return factory;
}
}
public class AbuseDesignPatterns {
public static void main(String[] args) {
AbstractFactory factory = FactoryMakerSingleton.getInstance().getFactory();
Subject subject = factory.createSubject();
subject.attach(factory.createObserver());
Command command = factory.createCommand(subject);
command.execute();
}
}
утащено отсюда:
http://taskinoor.wordpress.com/2...o-world-program/ |