Template mode (Template Pattern)

Template mode (Template Pattern)

An abstract class (template) defines the method of implementation class, subclass specific realization of the template method, called when the abstract class way call.
Objective: skeleton class defines a method, extended to achieve specific subclasses.
The main solution: some of the ways GM, but in each sub-category are overridden this method.
When to use : Some common methods.
How to solve: these general algorithm in the abstract template.
The key code: implemented in an abstract class, other steps implemented in a subclass.
Be used: a plurality of sub-class have a common method, and the same logic; repeat complicated methods.
Advantages: no need to change the portion of the package, the extended portion may be varied; extracting common code, easy to maintain; behavior controlled by the parent, (in particular) receiving class implemented by subclasses.
Cons: each of the different sub-class implementation will need to write a subclass of a template, increase the number of sub-categories, large systems.
Note: to prevent malicious acts, the template method generally add the final keyword.

Create an abstract class (template)

. 1  / ** 
2  * @author : wooch
 . 3  * @Create: 2020/02/14
 . 4   * / 
. 5  public  abstract  class Game {
 . 6      abstract  void the initialize ();
 . 7      abstract  void startPlay ();
 . 8      abstract  void endPlay ();
 9      // template 
10      public  Final  void Play () {
 . 11          // initialization 
12 is          the initialize ();
 13 is          // start 
14          startPlay ();
15          // End 
16          endPlay ();
 . 17      }
 18 is }

Create a subclass (Cricket)

 1 /**
 2  * @author: wooch
 3  * @create: 2020/02/14
 4  */
 5 public class Cricket extends Game {
 6     @Override
 7     void initialize() {
 8         System.out.println("Cricket Game Initialized!");
 9     }
10 
11     @Override
12     void startPlay() {
13         System.out.println("Cricket Game Started.");
14     }
15 
16     @Override
17     void endPlay() {
18         System.out.println("Cricket Game Finished.");
19     }
20 }

Create a subclass (Football)

 1 /**
 2  * @author: wooch
 3  * @create: 2020/02/14
 4  */
 5 public class Football extends Game {
 6     @Override
 7     void initialize() {
 8         System.out.println("Football Game Initialized!");
 9     }
10 
11     @Override
12     void startPlay() {
13         System.out.println("Football Game Started.");
14     }
15 
16     @Override
17     void endPlay() {
18         System.out.println("Football Game Finished.");
19     }
20 }

Demonstration Results

 1 /**
 2  * @author: wooch
 3  * @create: 2020/02/14
 4  */
 5 public class TemplatePatternTest {
 6     public static void main(String[] args) {
 7         Game game = new Cricket();
 8         game.play();
 9         System.out.println();
10         game = new Football();
11         game.play();
12     }
13 }

operation result

1 Cricket Game Initialized!
2 Cricket Game Started.
3 Cricket Game Finished.
4 
5 Football Game Initialized!
6 Football Game Started.
7 Football Game Finished.