Detailed description of Design Pattern-composite pattern

Composite pattern

Address: http://blog.csdn.net/caroline_wendy

Combination Mode: allows you to combine objects into a tree structure to express the "Overall/partial" hierarchy. combination allows you to process individual objects and composite objects in a consistent way.

CreateComponent class and Composite)AndLeaf (leaf)Inherit component classes,Client)Directly call the top-level composite class.

Specific Method:

1.Component class)Contains the methods used by composite and leaf, that is, a node of the tree structure. abstract is used ).

If not definedException).

/*** @ Time July 4, 2014 */package composite;/*** @ author C. l. wang **/public abstract class menucomponent {public void add (menucomponent) {Throw new unsupportedoperationexception (); // if not provided, you cannot call} public void remove (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 Boolean isvegetarian () {Throw new unsupportedoperationexception ();} public void print () {Throw new unsupportedoperationexception ();}}

2. Leaf (leaf)Inherits component classes to implement specific output methods.

/*** @ Time July 4, 2014 */package composite;/*** @ author C. l. wang **/public class menuitem extends menucomponent {string name; string description; Boolean vegetarian; double price;/*****/Public menuitem (string name, string description, Boolean vegetarian, double price) {// todo auto-generated constructor stubthis. name = Name; this. description = description; this. vegetarian = vegetarian; this. price = price;} Public String getname () {return name;} Public String getdescription () {return description;} public double getprice () {return price;} public Boolean isvegetarian () {return vegetarian;} public void print () {system. out. print ("" + getname (); If (isvegetarian () {system. out. print ("(v)");} system. out. println ("," + getprice (); system. out. println ("--" + getdescription ());}}

3. Composite)Inherit component classes and implement the required methods. You can add some leaf classes (leaf) as subnodes.

/*** @ Time July 4, 2014 */package composite; import Java. util. arraylist; import Java. util. iterator;/*** @ author C. l. wang **/Public Class Menu extends menucomponent {arraylist <menucomponent> menucomponents = new arraylist <menucomponent> (); string name; string description; /*****/Public menu (string name, string description) {// todo auto-generated constructor stubthis. name = Name; this. description = description;} public void add (menucomponent) {menucomponents. add (menucomponent);} public void remove (menucomponent) {menucomponents. remove (menucomponent);} public menucomponent getchild (int I) {return (menucomponent) menucomponents. get (I) ;}public string getname () {return name;} Public String getdescription () {return description;} public void print () {system. out. print ("\ n" + getname (); system. out. println ("," + getdescription (); system. out. println ("--------------------"); iterator <menucomponent> iterator = menucomponents. iterator (); While (iterator. hasnext () {menucomponent = (menucomponent) iterator. next (); menucomponent. print ();}}}

4. Client)You can directly call the composite.

/*** @ Time July 4, 2014 */package composite;/*** @ author C. l. wang **/public class waitress {menucomponent allmenus;/*****/Public waitress (menucomponent allmenus) {// todo auto-generated constructor stubthis. allmenus = allmenus;} public void printmenu () {allmenus. print ();}}

5. test:

/*** @ Time July 4, 2014 */package composite;/*** @ author C. l. wang **/public class menutestdrive {/*** @ Param ARGs */public static void main (string [] ARGs) {// todo auto-generated method stubmenucomponent pancakehousemenu = new menu ("Pancake House menu", "Breakfast"); menucomponent dinermenu = new menu ("Diner menu ", "lunch"); menucomponent cafemenu = new menu ("cafe menu", "dinner"); menucomponent Dess Ertmenu = new menu ("dessert menu", "dessert course! "); Menucomponent coffeemenu = new menu (" coffee menu "," stuff to go with your afternoon coffee "); menucomponent allmenus = new menu (" All Menus ", "All menus combined"); allmenus. add (pancakehousemenu); allmenus. add (dinermenu); allmenus. add (cafemenu); pancakehousemenu. add (New menuitem ("K & B's pancake breakfast", "pancakes with scrambled eggs, and toast", true, 2.99); pancakehousemenu. add (New menuitem ("regular pancake breakfast", "pancakes with fried eggs, sausage", false, 2.99); pancakehousemenu. add (New menuitem ("Blueberry Pancakes", "pancakes made with fresh blueberries, and blueberry syrup", true, 3.49); pancakehousemenu. add (New menuitem ("waffles", "waffles, with your choice of blueberries or strawberries", true, 3.59); dinermenu. add (New menuitem ("vegetarian BLT", "(fakin ') bacon with lettuce & tomato on whole wheat", true, 2.99); dinermenu. add (New menuitem ("BLT", "bacon with lettuce & tomato on whole wheat", false, 2.99); dinermenu. add (New menuitem ("soup of the day", "a bowl of the soup of the day, with a side of potato salad", false, 3.29); dinermenu. add (New menuitem ("hotdog", "a hot dog, with saurkraut, relish, onions, topped with cheese", false, 3.05); dinermenu. add (New menuitem ("steamed veggies and brown rice", "steamed vegetables over brown rice", true, 3.99); dinermenu. add (New menuitem ("Pasta", "spaghetti with marinara sauce, and a slice of sourdough bread", true, 3.89); dinermenu. add (dessertmenu); dessertmenu. add (New menuitem ("apple pie", "apple pie with a flakey crust, topped with vanilla icecream", true, 1.59); dessertmenu. add (New menuitem ("Cheesecake", "creamy New York cheesecake, with a chocolate Graham crust", true, 1.99); dessertmenu. add (New menuitem ("sorbet", "a scoop of raspberry and a scoop of Lime", true, 1.89); cafemenu. add (New menuitem ("Veggie burger and air fries", "Veggie burger on a whole wheat bun, lettuce, tomato, and fries", true, 3.99); cafemenu. add (New menuitem ("soup of the day", "a cup of the soup of the day, with a side salad", false, 3.69); cafemenu. add (New menuitem ("burrito", "a large burrito, with whole pinto beans, salsa, Guacamole", true, 4.29); cafemenu. add (coffeemenu); coffeemenu. add (New menuitem ("coffee cake", "crumbly cake topped with cinnamon and walnuts", true, 1.59); coffeemenu. add (New menuitem ("bagel", "flavors include sesame, poppyseed, cinnamon raisin, Pumpkin", false, 0.69); coffeemenu. add (New menuitem ("biscotti", "Three almond or hazelnut biscotti cookies", true, 0.89); waitress = new waitress (allmenus); waitress. printmenu ();}}

6. Output:

ALL MENUS, All menus combined--------------------PANCAKE HOUSE MENU, Breakfast-------------------- K&B‘s Pancake Breakfast(v), 2.99    -- Pancakes with scrambled eggs, and toast Regular Pancake Breakfast, 2.99    -- Pancakes with fried eggs, sausage Blueberry Pancakes(v), 3.49    -- Pancakes made with fresh blueberries, and blueberry syrup Waffles(v), 3.59    -- Waffles, with your choice of blueberries or strawberriesDINER MENU, Lunch-------------------- Vegetarian BLT(v), 2.99    -- (Fakin‘) Bacon with lettuce & tomato on whole wheat BLT, 2.99    -- Bacon with lettuce & tomato on whole wheat Soup of the day, 3.29    -- A bowl of the soup of the day, with a side of potato salad Hotdog, 3.05    -- A hot dog, with saurkraut, relish, onions, topped with cheese Steamed Veggies and Brown Rice(v), 3.99    -- Steamed vegetables over brown rice Pasta(v), 3.89    -- Spaghetti with Marinara Sauce, and a slice of sourdough breadDESSERT MENU, Dessert course!-------------------- Apple Pie(v), 1.59    -- Apple pie with a flakey crust, topped with vanilla icecream Cheesecake(v), 1.99    -- Creamy New York cheesecake, with a chocolate graham crust Sorbet(v), 1.89    -- A scoop of raspberry and a scoop of limeCAFE MENU, Dinner-------------------- Veggie Burger and Air Fries(v), 3.99    -- Veggie burger on a whole wheat bun, lettuce, tomato, and fries Soup of the day, 3.69    -- A cup of the soup of the day, with a side salad Burrito(v), 4.29    -- A large burrito, with whole pinto beans, salsa, guacamoleCOFFEE MENU, Stuff to go with your afternoon coffee-------------------- Coffee Cake(v), 1.59    -- Crumbly cake topped with cinnamon and walnuts Bagel, 0.69    -- Flavors include sesame, poppyseed, cinnamon raisin, pumpkin Biscotti(v), 0.89    -- Three almond or hazelnut biscotti cookies