Java - 觀察模式 - 觀察一個班級，但可以訪問另一個班級正在觀察的內容

Question

我正在創建一個空中交通管制系統。我有一個叫做plane的類，它是一個被觀察到的任何改變，這個改變是隨機生成一個平面時名稱改變的。問題是機場需要訪問名稱以將名稱存儲到數組列表中，如果我可以將其存儲到數組列表中，則可以使其工作。反正這是機場類的代碼：

/* 
* To change this template, choose Tools | Templates 
* and open the template in the editor. 
*/ 

package airtrafficcontrolv3; 
import java.util.*; 
import java.util.logging.Level; 
import java.util.logging.Logger; 

/** 
* 
* @author 
*/ 
public class Airport 
{ 
     Subject s = new SubjectImpl(); 

    Plane point = new Plane(); 
    Queue <String> waiting = new LinkedList<String>(); 

    public Airport() 
    { 
     //String name = 
     s.getState(); 
     System.out.println(s); 

     while (!waiting.isEmpty()) 
     { 
      System.out.println("Waiting to take off: "+waiting); 
      try 
      { 
       System.out.println("Preparing to taxi: "+waiting.remove()); 
       Thread.sleep(5000); 
      } 
      catch (InterruptedException ex) 
      { 
       Logger.getLogger(Airport.class.getName()).log(Level.SEVERE, null, ex); 
      } 
     } 
    } 

} 

我不知道，如果我必須有獲得正被觀察到的問題，我有一個方法有getstate這是目前的是什麼主題指出，但是它有隨機數字和字母出來產生：

airtrafficcontrolv3.SubjectImpl@5a199939 

這是我在我的主題類：

package airtrafficcontrolv3; 

/* 
* @author S0082708 
*/ 

import java.util.ArrayList; 
import java.util.Iterator; 
import java.util.List; 

interface Subject 
{ 

    public void addObserver(Observer o); 

    public void removeObserver(Observer o); 

    public String getState(); 

    public void setState(String state); 
} 

/* 
* Creates an observer that will watch for any changes 
*/ 

interface Observer 
{ 
    public void update(Subject o); 
} 

/* 
* Class implements the observer 
* Observer is what is doing the watching 
* The string is set to blank waiting ready for any updates that will occur 
* Anything in getState is then passed to state 
*/ 
class ObserverImpl implements Observer 
{ 
    private String state = ""; 

    public void update(Subject o) 
    { 
     state = o.getState(); 

     //Need to add text to the label 
     // AirTrafficControlv3View.Incoming.add(state); 

    } 
} 

/* 
* Subject is what is being watched 
* The array is then created to store the information ready to add further information 
* Or ready to delete 
* State is set to blank ready for whatever information is being passed 
*/ 

class SubjectImpl implements Subject 
{ 

    private List observers = new ArrayList(); 
    private String state = ""; 

    /* 
    * Returns whatever is being passed to state 
    */ 

    public String getState() 
    { 
     //System.out.println(state); 
     return state; 
    } 

    /* 
    * Sets the state to current state and then notifies the observer of the changes 
    * Made to the state ready to update 
    */ 
    public void setState(String state) 
    { 
     this.state = state; 
     notifyObservers(); 
    } 

    /* 
    * Adds the observer along with the name, so several observers can be implemented 
    */ 
    public void addObserver(Observer o) 
    { 
     observers.add(o); 
    } 

    /* 
    * Removes the observer once it has been used 
    */ 

    public void removeObserver(Observer o) 
    { 
     observers.remove(o); 
    } 

    /* 
    * The iterator allows the ability to loop through the array 
    * While the iterator has a next then it allows the ability to take in more 
    * Changes to be observed. It is then updated with the current information 
    */ 

    public void notifyObservers() 
    { 
     Iterator i = observers.iterator(); 
     while (i.hasNext()) 
     { 
      Observer o = (Observer) i.next(); 
      o.update(this); 
     }  
    } 
} 

任何人都可以點我在正確的方向如何從荷航取得狀態這一點出來，因爲荷航正好出現，但它不會在機場班出來。

任何建議將大受歡迎。

Answer 1

您需要的類，它是指向的對象來你從getState()返回你得到的隨機數是toString()在Object類呈現例如身份，而不是內容的默認實現來實現toString()。