localinnerclass.java

Java面向对象编程(随书配套源代码) 阐述了面向对象编程的思想

package chapter7;
import java.util.*;
public class LocalInnerClass
{
	 String str1 = "我是一个外部类的实例变量";
	 static String str2 = "我是一个外部类的静态变量";
	  static class ComputerLanguage 
	 {		
	 	private String name;
	 	ComputerLanguage (String name)
	 	{
	 	   this.name = name;
	 	}
	 	public String toString ()
	 	{
	 	   return name;
	 	}
	 }
	 
	static  Enumeration enumerator (final Object [] array)
	{
		final int  localVar1= 1;
		class LocalInner   implements Enumeration //本地方法只允许是abstract或final的。
		{
			private   int index = 0;
			public boolean hasMoreElements ()
			{
			    int i= localVar1 ;  //只能引用final局部变量，不能引用非final局部变量或参数
				return index < array.length;
			}
			public Object nextElement ()
			{
			        return array [index++].toString ();
			}
			public void display() //
			{
				System.out.println(str2);
			}
		}
		LocalInner local = new LocalInner ();
		local.display();
		return new LocalInner ();
	}
	
	 public static void main (String [] args)
	{
		 
		 ComputerLanguage [] cl =
		{
			new ComputerLanguage ("BASIC"),
			new ComputerLanguage ("C"),
			new ComputerLanguage ("C++"),
			new ComputerLanguage ("Cobol"),
			new ComputerLanguage ("Forth"),
			new ComputerLanguage ("Fortran"),
			new ComputerLanguage ("Java"),
			new ComputerLanguage ("LISP"),
			new ComputerLanguage ("Logo"),
			new ComputerLanguage ("Modula 2"),
			new ComputerLanguage ("Pascal"),
			new ComputerLanguage ("Perl"),
			new ComputerLanguage ("Prolog"),
			new ComputerLanguage ("Snobol")
		};
	   Enumeration e = enumerator ((Object []) cl);
	   while (e.hasMoreElements ())
	   System.out.println (e.nextElement ());
	}
}