% find . -name "*.java" -print0 |xargs -0 cat []
public class DigitObserver implements Observer {
@Override
public void update(NumberGenerator generator) {
System.out.println("DigitObserver:" + generator.getNumber());
try {
Thread.sleep(100);
} catch (Exception e) {
}
}
}
public class GraphObserver implements Observer {
@Override
public void update(NumberGenerator generator) {
System.out.print("GraphObserver:");
for (int i = 0, l = generator.getNumber(); i < l; i++) {
System.out.print("*");
}
System.out.println("");
try {
Thread.sleep(100);
} catch (Exception e) {
}
}
}
public class Main {
public static void main(String[] args) {
NumberGenerator generator = new RandomNumberGenerator();
Observer observer1 = new DigitObserver();
Observer observer2 = new GraphObserver();
generator.addObserver(observer1);
generator.addObserver(observer2);
generator.execute();
}
}
import java.util.ArrayList;
import java.util.List;
public abstract class NumberGenerator {
private List<Observer> observers = new ArrayList<>();
public void addObserver(Observer observer) {
observers.add(observer);
}
public void deleteObserver(Observer observer) {
observers.remove(observer);
}
public void notifyObservers() {
for (Observer obs : observers) {
obs.update(this);
}
}
public abstract int getNumber();
public abstract void execute();
}
public interface Observer {
public abstract void update(NumberGenerator generator);
}
import java.util.Random;
public class RandomNumberGenerator extends NumberGenerator {
private Random random = new Random();
private int number;
@Override
public int getNumber() {
return number;
}
@Override
public void execute() {
for (int i = 0; i < 20; i++) {
number = random.nextInt(50);
notifyObservers();
}
}
}
DigitObserver:42
GraphObserver:******************************************
DigitObserver:44
GraphObserver:********************************************
DigitObserver:46
GraphObserver:**********************************************
DigitObserver:15
GraphObserver:***************
DigitObserver:3
GraphObserver:***
DigitObserver:18
GraphObserver:******************
DigitObserver:13
GraphObserver:*************
DigitObserver:26
GraphObserver:**************************
DigitObserver:33
GraphObserver:*********************************
DigitObserver:35
GraphObserver:***********************************
DigitObserver:9
GraphObserver:*********
DigitObserver:29
GraphObserver:*****************************
DigitObserver:28
GraphObserver:****************************
DigitObserver:25
GraphObserver:*************************
DigitObserver:23
GraphObserver:***********************
DigitObserver:4
GraphObserver:****
DigitObserver:29
GraphObserver:*****************************
DigitObserver:24
GraphObserver:************************
DigitObserver:26
GraphObserver:**************************
DigitObserver:5
GraphObserver:*****
