迭代器模式实例与解析---实例：电视机遥控器

电视机遥控器就是一个迭代器的实例，通过它可以实现对电视机频道集合的遍历操作，本实例我们将模拟电视机遥控器的实现。

public class Client
{
	public static void display(Television tv)
	{
		TVIterator i=tv.createIterator();
		System.out.println("电视机频道：");
		while(!i.isLast())
		{
			System.out.println(i.currentChannel().toString());
			i.next();
		}
	}
	
	public static void reverseDisplay(Television tv)
	{
		TVIterator i=tv.createIterator();
		i.setChannel(5);
		System.out.println("逆向遍历电视机频道：");
		while(!i.isFirst())
		{
			i.previous();
			System.out.println(i.currentChannel().toString());
		}
	}
	
	public static void main(String a[])
	{
		Television tv;
		tv=(Television)XMLUtil.getBean();
		display(tv);
		System.out.println("--------------------------");
		reverseDisplay(tv);
	}
}

public class SkyworthTelevision implements Television
{
	private Object[] obj={"CCTV-1","CCTV-2","CCTV-3","CCTV-4","CCTV-5","CCTV-6","CCTV-7","CCTV-8"};
	public TVIterator createIterator()
	{
		return new SkyworthIterator();
	}

	private class SkyworthIterator implements TVIterator
	{
	   	private int currentIndex=0;
	   	 	
		public void next()
		{
			if(currentIndex<obj.length)
			{
				currentIndex++;
			}
		}
		
		public void previous()
		{
			if(currentIndex>0)
			{
				currentIndex--;
			}
		}	
		
		public void setChannel(int i)
		{
			currentIndex=i;
		}
		
		
		public Object currentChannel()
		{
			return obj[currentIndex];
		}
		
		public boolean isLast()
		{
			return currentIndex==obj.length;
		}
		
		public boolean isFirst()
		{
			return currentIndex==0;
		}
	}
}

public class TCLTelevision implements Television
{
	private Object[] obj={"湖南卫视","北京卫视","上海卫视","湖北卫视","黑龙江卫视"};
	public TVIterator createIterator()
	{
		return new TCLIterator();
	}
   
	class TCLIterator implements TVIterator
	{
	   	private int currentIndex=0;
	   	 	
		public void next()
		{
			if(currentIndex<obj.length)
			{
				currentIndex++;
			}
		}
		
		public void previous()
		{
			if(currentIndex>0)
			{
				currentIndex--;
			}
		}	
		
		public void setChannel(int i)
		{
			currentIndex=i;
		}
		
		
		public Object currentChannel()
		{
			return obj[currentIndex];
		}
		
		public boolean isLast()
		{
			return currentIndex==obj.length;
		}
	
		public boolean isFirst()
		{
			return currentIndex==0;
		}
	}
}

public interface Television
{
	TVIterator createIterator();
}

public interface TVIterator
{
	void setChannel(int i);
	void next();
	void previous();
	boolean isLast();
	Object currentChannel();
    boolean isFirst();
}

import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.SAXException;
import java.io.*;
public class XMLUtil
{
//该方法用于从XML配置文件中提取具体类类名，并返回一个实例对象
	public static Object getBean()
	{
		try
		{
			//创建文档对象
			DocumentBuilderFactory dFactory = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = dFactory.newDocumentBuilder();
			Document doc;							
			doc = builder.parse(new File("config.xml")); 
		
			//获取包含类名的文本节点
			NodeList nl = doc.getElementsByTagName("className");
            Node classNode=nl.item(0).getFirstChild();
            String cName=classNode.getNodeValue();
            
            //通过类名生成实例对象并将其返回
            Class c=Class.forName(cName);
	  	    Object obj=c.newInstance();
            return obj;
           }   
           	catch(Exception e)
           	{
           		e.printStackTrace();
           		return null;
           	}
		}
}

配置文件
<?xml version="1.0"?>
<config>
	<className>SkyworthTelevision</className>
</config>

标签：return,void,CCTV,public,---,实例,currentIndex,obj,遥控器
来源： https://blog.csdn.net/bueke/article/details/117898787