ai: Observer Pattern

package my.observer;

public class WeatherVO {

 private int temperature;

 private int humidity;

 private int pressure;

 public WeatherVO(){}

 public WeatherVO(int temperature, int humidity, int pressure){

  this.temperature = temperature;

  this.humidity = humidity;

  this.pressure = pressure;

}

 public int getTemperature() {

  return temperature;

}

 public void setTemperature(int temperature) {

  this.temperature = temperature;

}

 public int getHumidity() {

  return humidity;

}

 public void setHumidity(int humidity) {

  this.humidity = humidity;

}

 public int getPressure() {

  return pressure;

}

 public void setPressure(int pressure) {

  this.pressure = pressure;

}

}

package my.observer;

public interface DataSource {

 public void print();

 public WeatherVO getWeather();

}

package my.observer;

public class WeatherMeasure implements DataSource{

 private WeatherVO weather;

 public WeatherMeasure(WeatherVO weather){

  this.weather = weather;

}

 @Override

 public WeatherVO getWeather(){

  return weather;

}

 @Override

 public void print(){

  String query = weather.getTemperature() + " / " + weather.getHumidity() + " / " + weather.getPressure();

  System.out.println(query);

}

}

package my.observer;

public interface Notification {

 public void addObserver(Observer observer);

 public Observer removeObserver(Observer observer);

 public void notifyObserver();

}

package my.observer;

import java.util.ArrayList;

public class WeatherData implements Notification{

 protected ArrayList<Observer> observers = new ArrayList<>();

 private DataSource dataSource;

 public WeatherData(DataSource dataSource){

  this.dataSource = dataSource;

}

 @Override

 public void addObserver(Observer observer) {

  for(Observer o : observers){

   if(o.equals(observer)) return;

}

  observers.add(observer);

}

 @Override

 public Observer removeObserver(Observer observer) {

  for(int i=0; i<observers.size(); ++i){

   if(observers.get(i).equals(observer)){

    observers.remove(i); break;

}

}

  return null;

}

 @Override

 public void notifyObserver() {

  for(int i=0; i<observers.size(); ++i) observers.get(i).update(dataSource);

}

}

package my.observer;

public interface Observer {

 public void update(DataSource dataSource);

}

package my.observer;

public class ConditionView implements Observer{

 @Override

 public void update(DataSource dataSource) {

  dataSource.print();

}

}

package my.observer;

public class ExplainView implements Observer{

 @Override

 public void update(DataSource dataSource) {

  WeatherVO vo = dataSource.getWeather();

  System.out.println("온도 : " + vo.getTemperature());

  System.out.println("습도 : " + vo.getHumidity());

  System.out.println("기압 : " + vo.getPressure());

}

}

package my.observer;

import org.junit.Test;

public class WeatherTest {

 @Test

 public void test(){

  WeatherVO vo = new WeatherVO(5, 6, 7);

  WeatherData weather = new WeatherData(new WeatherMeasure(vo));

  Observer conditionView = new ConditionView();

  Observer explainView = new ExplainView();

  weather.addObserver(conditionView);

  weather.addObserver(explainView);

  weather.removeObserver(conditionView);

  weather.notifyObserver();

}

}

ai