package com.pattern.Observer;

import java.util.ArrayList;
/**
 *3．具体主题 
 */
public class SeekJobCenter implements Subject {
	String mess;
	boolean changed;
	ArrayList<Observer> personList;
	
	public SeekJobCenter(){
		personList = new ArrayList<Observer>();
		mess="no news is good news!";
		changed = false;
	}
	
	@Override
	public void AddObserver(Observer o) {
		if(!personList.contains(o)){
			personList.add(o);
		}
	}

	@Override
	public void DeleteObserver(Observer o) {
		if(personList.contains(o)){
			personList.remove(o);
		}
	}

	@Override
	public void NotifyObserver() {
		if(changed){
			for(int i = 0 ; i < personList.size(); i++){
				Observer observer = personList.get(i);
				observer.hearTelephone(mess);
			}
		changed = false;
		}
	}
	
	public void GiveNewMess(String newMess){
		if(newMess.equals(mess)){
			changed = false;
		}else{
			mess = newMess;
			changed = true;
		}
	}

}