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我正在创建一个空中交通管制系统。我有一个名为 plane 的类,它可以观察到任何变化,即随机生成飞机时名称会发生​​变化。问题是机场需要访问该名称以将其存储到一个数组列表中,如果我可以让它工作的话,可能是一个队列。无论如何,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);
            }
        }
    }

}

我不确定我是否必须访问正在观察的主题,因为在主题中我有一个 getstate 方法,这是当前所指向的,但是它以随机数字和字母生成:

airtrafficcontrolv3.SubjectImpl@5a199939

这是我在我的学科课上的:

    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);
        }      
    }
}

谁能指出我正确的方向,即如何从 get state 中获取字符串,该字符串以 KLM 的形式出现,但它不会在机场类中出现。

任何建议都将受到欢迎。

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1 回答 1

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您需要toString()在从您获得的随机数返回的对象的类中实现 a ,这是在呈现实例标识而不是内容的类中getState()的默认实现。toString()Object

于 2012-04-07T10:32:23.507 回答