iterator component

1 抽象类组合

public abstract class MenuComponent {

public void add(MenuComponent menuComponent) {

throw new UnsupportedOperationException();

}

public void remove(MenuComponent menuComponent) {

throw new UnsupportedOperationException();

}

public MenuComponent getChild(int i) {

throw new UnsupportedOperationException();

}

public String getName() {

throw new UnsupportedOperationException();

}

public String getDescription() {

throw new UnsupportedOperationException();

}

public double getPrice() {

throw new UnsupportedOperationException();

}

public void print() {

throw new UnsupportedOperationException();

}

}

2 list 

public class Menu extends MenuComponent {

private String name;

private String description;

List<MenuComponent> list = new ArrayList<MenuComponent>();

public Menu(String name, String description) {

this.name = name;

this.description = description;

}

@Override

public void add(MenuComponent menuComponent) {

list.add(menuComponent);

}

@Override

public void remove(MenuComponent menuComponent) {

list.remove(menuComponent);

}

@Override

public MenuComponent getChild(int i) {

return list.get(i);

}

@Override

public void print() {

System.out.println("Menu------------" + this.name);

for(MenuComponent c : list) {

c.print();

}

}

@Override

public String getName() {

return this.name;

}

@Override

public String getDescription() {

return this.description;

}

}

3 数组  实现Iterator 

public class ArrayMenu extends MenuComponent implements Iterator<MenuComponent>{

private String name;

private String description;

private final int size = 6;

private int position = 0;

private int iPosition = 0;

MenuComponent[] array = new MenuComponent[size];

public ArrayMenu(String name, String description) {

this.name = name;

this.description = description;

}

@Override

public void add(MenuComponent menuComponent) {

array[position] = menuComponent;

position ++;

}

@Override

public void remove(MenuComponent menuComponent) {

if(position < 0) {

throw new IllegalStateException("You can't remove an item until you have done at least one nexe");

}else {

if(array[position] != null) {

for(int i=position-1; i<size-1; i++) {

array[i] = array[i+1];

}

array[size-1] = null;

}

}

}

@Override

public MenuComponent getChild(int i) {

return array[i];

}

@Override

public void print() {

System.out.println("arrayNume: " + this.name);

while(hasNext()) {

MenuComponent c = next();

if(c != null) {

c.print();

}

}

}

@Override

public String getName() {

return this.name;

}

@Override

public String getDescription() {

return this.description;

}

@Override

public boolean hasNext() {

if(iPosition < array.length) {

return true;

}else {

return false;

}

}

@Override

public MenuComponent next() {

if(iPosition < array.length) {

return array[iPosition++];

}

return null;

}

@Override

public void remove() {

throw new UnsupportedOperationException();

}

}

4. MenuItem

public class MenuItem extends MenuComponent {

private String name;

private String description;

private double price;

public MenuItem(String name, String description, double price) {

this.name = name;

this.description = description;

this.price = price;

}

@Override

public String getName() {

return this.name;

}

@Override

public String getDescription() {

return this.description;

}

@Override

public double getPrice() {

return this.price;

}

@Override

public void print() {

System.out.println("name:" + this.name + " description: " + this.description + " price: " + this.price);

}

}

5 Test

public class Test {

public static void main(String[] args) {

Menu item = new Menu("listMenu", "listItem");

item.add(new MenuItem("menu1", "menu1111", 100));

item.add(new MenuItem("menu2", "menu2222", 200));

item.add(new MenuItem("menu3", "menu3333", 300));

item.print();

ArrayMenu arrayMenu = new ArrayMenu("arrayMenu", "arrayMenu");

arrayMenu.add(new MenuItem("menu4", "Menu44", 400));

arrayMenu.add(new MenuItem("menu5", "Menu55", 500));

arrayMenu.add(new MenuItem("menu6", "Menu66", 600));

arrayMenu.print();

}

}

6 输出

Menu------------listMenu

name:menu1 description: menu1111 price: 100.0

name:menu2 description: menu2222 price: 200.0

name:menu3 description: menu3333 price: 300.0

arrayNume: arrayMenu

name:menu4 description: Menu44 price: 400.0

name:menu5 description: Menu55 price: 500.0

name:menu6 description: Menu66 price: 600.0