java設(shè)計(jì)模式之迭代器模式

2019-11-14 09:51:27

字體：大中小

供稿：網(wǎng)友

迭代器模式：提供一種方法順序訪問一個(gè)聚合對(duì)象中的各個(gè)元素，而又不暴露其內(nèi)部的表示。

類圖：這里寫圖片描述使用迭代器模式，實(shí)現(xiàn)了烤魚菜單，類圖： MenuItem類代碼實(shí)現(xiàn)：

public class MenuItem { String name; public MenuItem(String name){ this.name = name; } public String getname(){ return name; }}

接口Iterator代碼實(shí)現(xiàn)：

public interface Iterator { public boolean hasNext(); public Object next(); public void remove();}

類FishIterator代碼實(shí)現(xiàn)：

public class FishIterator implements Iterator{ MenuItem[] items; int position = 0; public FishIterator(MenuItem[] items){ this.items = items; } @Override public boolean hasNext() { // TODO Auto-generated method stub if (position >=items.length || items[position] == null) { return false; }else { return true; } } @Override public Object next() { // TODO Auto-generated method stub MenuItem menuItem = items[position]; position = position + 1; return menuItem; } @Override public void remove() { // TODO Auto-generated method stub for (int i = position; i < (items.length -1); i++) { items[i] = items[i+1]; } items[items.length - 1] = null; }}

接口Menu代碼實(shí)現(xiàn)：

public interface Menu { public Iterator createIterator();}

類FishMenu代碼實(shí)現(xiàn)：

public class FishMenu implements Menu{ MenuItem[] items; static final int MAX_ITEMS = 6; int numberOfItems = 0; public FishMenu(){ items = new MenuItem[MAX_ITEMS]; addItem("烤鯽魚"); addItem("烤草魚"); addItem("烤大頭魚"); addItem("烤秋刀魚"); addItem("烤鯊魚"); } public void addItem(String name){ MenuItem menuItem = new MenuItem(name); if (numberOfItems >= MAX_ITEMS) { System.out.