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java composite pattern

Grotesque Gibbon answered on October 19, 2022 Popularity 9/10 Helpfulness 1/10

answer java composite pattern

java composite pattern

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// Java Composite Pattern
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 boolean isVegetarian() {
		throw new UnsupportedOperationException();
	}
	public void print() {
		throw new UnsupportedOperationException();
	}
}

public class Menu extends MenuComponent {	// Composite 
	ArrayList<MenuComponent> menuComponents = new ArrayList<>();
	String name;
  
	public Menu(String name) {this.name = name;}
 
	public void add(MenuComponent menuComponent) {
		menuComponents.add(menuComponent);
	}
	public void remove(MenuComponent menuComponent) {
		menuComponents.remove(menuComponent);
	}
	public MenuComponent getChild(int i) {
		return (MenuComponent)menuComponents.get(i);
	}
 
	public String getName() {return name;}
 
	public void print() {
		System.out.print("\n" + getName());
		System.out.println("---------------------");
		for (MenuComponent component: this.menuComponents) {
			component.print();		// print recursively
		}
	}
}

public class MenuItem extends MenuComponent { // Leaf
	String name;
	boolean vegetarian;
    
	public MenuItem(String name, boolean vegetarian) 
	{ 
		this.name = name;
		this.vegetarian = vegetarian;
	}

	public String getName() {return name;}
	public boolean isVegetarian() {return vegetarian;}
  
	public void print() {
		System.out.print("  " + getName());
		if (isVegetarian()) {
			System.out.print("(v)");
		}
	}
}

public class Waitress {		// Client
	MenuComponent allMenus;
 
	public Waitress(MenuComponent allMenus) {
		this.allMenus = allMenus;
	}
	public void printMenu() {
		allMenus.print();	// print recursively
	}
}

public class MenuTestDrive {
	public static void main(String args[]) {
		MenuComponent breakfastMenu = new Menu("BREAKFAST MENU");
		MenuComponent dinerMenu = new Menu("DINER MENU");
		MenuComponent dessertMenu = new Menu("DESSERT MENU");
		MenuComponent allMenus = new Menu("ALL MENUS");
  
		allMenus.add(breakfastMenu);	//1st lvl Composite
		allMenus.add(dinerMenu);	//1st lvl Composite
  
		breakfastMenu.add(new MenuItem("Pancake", true));
		breakfastMenu.add(new MenuItem("Waffles", true));
		dinerMenu.add(new MenuItem("Hot Dog", false));
		dinerMenu.add(new MenuItem("Veggies", true));
   
		dinerMenu.add(dessertMenu);	//2nd lvl Composite
		dessertMenu.add(new MenuItem("Apple Pie",true));
 
		Waitress waitress = new Waitress(allMenus);
		waitress.printMenu();
	}
}

Popularity 9/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: composite java

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Contributed on Oct 19 2022

Grotesque Gibbon

0 Answers Avg Quality 2/10

java composite pattern

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