typescript: Template Method pattern

 

/**
 * Template Method pattern 模版方法是一种行为设计模式， 它在基类中定义了一个算法的框架， 允许子类在不修改结构的情况下重写算法的特定步骤。
 * file: Templatets.ts
 * The Abstract Class defines a template method that contains a skeleton of some
 * algorithm, composed of calls to (usually) abstract primitive operations.
 *
 * Concrete subclasses should implement these operations, but leave the template
 * method itself intact.
 */
abstract class AbstractClass {


    /**
     * The template method defines the skeleton of an algorithm.
     * 
     * @param strinuput 
     * @returns
     */
    public templateMethod(strinuput:string): string { //void
        let getstr="";
        this.baseOperation1();
        getstr=this.requiredOperations1(strinuput);
        this.baseOperation2();
        this.hook1();
        this.requiredOperation2(strinuput);
        this.baseOperation3();
        this.hook2();
        return getstr;
    }

    /**
     * These operations already have implementations.
     */
    protected baseOperation1(): void {
        console.log('AbstractClass says: I am doing the bulk of the work');
    }
    /**
     * 
     */
    protected baseOperation2(): void {
        console.log('AbstractClass says: But I let subclasses override some operations');
    }
    /**
     * 
     */
    protected baseOperation3(): void {
        console.log('AbstractClass says: But I am doing the bulk of the work anyway');
    }

    /**
     * These operations have to be implemented in subclasses.
     * @param strinuput 
     * @returns
     */
    protected abstract requiredOperations1(strinuput:string):string; //void

    /**
     * 
     * @param strinuput 
     */
    protected abstract requiredOperation2(strinuput:string): void;

    /**
     * These are "hooks." Subclasses may override them, but it's not mandatory
     * since the hooks already have default (but empty) implementation. Hooks
     * provide additional extension points in some crucial places of the
     * algorithm.
     */
    protected hook1(): void { }
    /**
     * 
     */
    protected hook2(): void { }
}

/**
 * Concrete classes have to implement all abstract operations of the base class.
 * They can also override some operations with a default implementation.
 */
class ConcreteClass1 extends AbstractClass {

    /**
     * 
     * @param strinuput 
     * @returns
     */
    protected requiredOperations1(strinuput:string):string { //void
        console.log('ConcreteClass1 says: Implemented Operation1,'+strinuput);
        return 'ConcreteClass1 says: Implemented Operation1,'+strinuput;

    }
    /**
     * 
     * @param strinuput 
     */
    protected requiredOperation2(strinuput:string): void {
        console.log('ConcreteClass1 says: Implemented Operation2,'+strinuput);
    }
}

/**
 * Usually, concrete classes override only a fraction of base class' operations.
 */
class ConcreteClass2 extends AbstractClass {

    /**
     * 
     * @param strinuput 
     * @returns
     */
    protected requiredOperations1(strinuput:string): string { //void
        console.log('ConcreteClass2 says: Implemented Operation1,'+strinuput);
        return 'ConcreteClass2 says: Implemented Operation1,'+strinuput;
    }
    /**
     * 
     * @param strinuput 
     */
    protected requiredOperation2(strinuput:string): void {
        console.log('ConcreteClass2 says: Implemented Operation2,'+strinuput);
    }
    /**
     * 
     */
    protected hook1(): void {
        console.log('ConcreteClass2 says: Overridden Hook1');
    }
}

let pubTemplate1="";
let pubTemplate2="";
let pubTemplate3="Geovin Du";
let pubTemplate4="geovindu";


/**
 * The client code calls the template method to execute the algorithm. Client
 * code does not have to know the concrete class of an object it works with, as
 * long as it works with objects through the interface of their base class.
 * 客户端显示
 * @param abstractClass 
 * @param strinput 
 */
function clientCodeTemplate(abstractClass: AbstractClass,strinput:string) {
    // ...
   return abstractClass.templateMethod(strinput);
    // ...
}




console.log('Same client code can work with different subclasses:');

pubTemplate1=clientCodeTemplate(new ConcreteClass1(),"geovindu");

console.log('');

console.log('Same client code can work with different subclasses:');
pubTemplate2=clientCodeTemplate(new ConcreteClass2(),"geovindu");

let messageTemplate: string = 'Hello World,This is a typescript!,涂聚文 Geovin Du.Web';
document.body.innerHTML = messageTemplate+",<br/>one="+pubTemplate1+",<br/>two="+pubTemplate2+",<br/>three="+pubTemplate3+",<br/>four="+pubTemplate4+",<br/>TypeScript Template Method pattern 模版模式";

　　

调用：

 

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <head><title>TypeScript Hello Template Method pattern 模版模式</title>
      <meta name="Description" content="geovindu,涂聚文,Geovin Du"/>
<meta name="Keywords" content="geovindu,涂聚文,Geovin Du"/>
<meta name="author" content="geovindu,涂聚文,Geovin Du"/> 
    </head>
    <body>
        <script src="dist/Templatets.js"></script>
    </body>
</html>

　　

 

输出：