《图解设计模式》章节试读

《图解设计模式》的笔记-第1章　Iterator模式——一个一个遍历 - 第1章　Iterator模式——一个一个遍历

Aggregate接口public interface Aggregate(){ public abstract Iterator iterator();} Iterator接口public interface Iterator(){ public abstract boolean hasNext(); public abstract object next();} Book类Public Class Book{ private String name; Public Book(String name){ this.name = name; } public String Getname(){ return this.name; }}BookShelf类public class BookShelf implements Aggregate{ private Book[] books; private int last = 0; public BookShelf(int maxsize){ this.books = new books[maxsize]; } public Book getBookAt(int i){ return books[i]; } public void appendBook(Book book){ this.book[last] = book; last++; } public int getLength(){ return length; } public Iterator iterator(){ return new BookShelfIterator(this); }}BookShelfIterator类public function BookShelfIterator implements Iterator{ private BookShelf bookShelf; private int index; public BookShelfIterator(BookShelf bookShelf){ this.bookShelf = bookShelf ; this.index = 0; } public boolean hasNext(){ if(index < bookShelf.getLength) return false; else return true; } Public Object next(){ Book book = bookShelf.getBookAt(index); index++; return book; }}Main类public Class Main{ public static void main(String [] args){ BookShelf bookShelf = new bookShelf(4); bookShelf.appendBook(new Book("a")); bookShelf.appendBook(new Book("b")); bookShelf.appendBook(new Book("c")); bookShelf.appendBook(new Book("d")); Iterator it = bookShelf.iterator(); while(it.hasNext()){ Book book = (Book)it.next(); System.out.printLn(book.getName()); } }}