Java - 观察模式 - 观察一个班级，但可以访问另一个班级正在观察的内容

Question

我正在创建一个空中交通管制系统。我有一个叫做plane的类，它是一个被观察到的任何改变，这个改变是随机生成一个平面时名称改变的。问题是机场需要访问名称以将名称存储到数组列表中，如果我可以将其存储到数组列表中，则可以使其工作。反正这是机场类的代码：

/* 
* 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，如果我必须有获得正被观察到的问题，我有一个方法有getstate这是目前的是什么主题指出，但是它有随机数字和字母出来产生：

airtrafficcontrolv3.SubjectImpl@5a199939 

这是我在我的主题类：

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); 
     }  
    } 
} 

任何人都可以点我在正确的方向如何从荷航取得状态这一点出来，因为荷航正好出现，但它不会在机场班出来。

任何建议将大受欢迎。

Answer 1

您需要的类，它是指向的对象来你从getState()返回你得到的随机数是toString()在Object类呈现例如身份，而不是内容的默认实现来实现toString()。