JAVA learning notes (13)-Template method mode template, learning notes Template

JAVA learning notes (13)-Template method mode template, learning notes Template
Template Method mode Template

/** Function: sorting and printing arrays ** definition: defines an algorithm (function) framework in the abstract class, and delays the specific steps in the subclass. * Composition: an abstract class, one or more implementation Classes * the abstract class contains: * 1. abstract method: defines only the specification and is implemented by sub-classes * 2. the template method is implemented by the parent class and the abstract method is called to complete the logic function. It is generally defined as a final method and does not allow subclass rewriting. ** advantages: * 1. scalability: add different implementation classes for extension * 2. ease of maintenance ** application: multiple sub-classes have the same method, and the logical functions of these methods are the same, we recommend that you use the template method mode */public abstract class Test03 {/** abstract method to sort arrays in ascending order */public abstract void sort (int [] nums ); /** template method: print the sorted array */public final void print (int [] nums) {this. sort (nums); // sorts the array System. out. println ("sorted array:"); for (int I = 0; I <nums. length; I ++) {System. out. print (nums [I] + "");}}}

Test class

/** Test class */public class Test {public static void main (String [] args) {int [] nums = {12, 45, 2,130, 43, 76, 3, 56}; Test03 test = new SubTest03 (); test. print (nums );}}

Inherited from Test03

/** Inherited from Test03 */public class SubTest03 extends Test03 {// override the sort method of the parent class public void sort (int [] nums) {for (int I = 0; I <nums. length-1; I ++) {for (int j = 0; j <nums. length-1-I; j ++) {if (nums [j] <nums [j + 1]) {int temp = nums [j]; nums [j] = nums [j + 1]; nums [j + 1] = temp ;}}}}}

Template Method Instance

/** Use mode and method mode to calculate the Volume */public class Test04 {public static void main (String [] args) {Volume v = new Cylinder (5.3, 4 ); system. out. println ("volume of the cylinder:" + v. getVolume (); v = new Cuboid (5, 3.2, 6.4); System. out. println ("cube volume:" + v. getVolume () ;}}/** Volume abstract class */abstract class Volume {private double height; // high public Volume (double height) {this. height = height;} public double getHeight () {return height;} // abstract method: calculate the area public abstract double getArea (); // template method: calculation Volume public double getVolume () {return getArea () * height ;}/ ** Cylinder class */class Cylinder extends Volume {private double r; // radius public Cylinder (double height, double r) {super (height); this. r = r ;}// Override the method of the parent class @ Override public double getArea () {return Math. PI * r; // calculate the area of the circle}/** Cuboid */class Cuboid extends Volume {private double length; // long private double width; // width public Cuboid (double height, double length, double width) {super (height); this. length = length; this. width = width;} // Override the method of the parent class @ Override public double getArea () {return length * width; // calculate the area of the rectangle }}