/**
* Proxy Pattern 代理是一种结构型设计模式， 让你能提供真实服务对象的替代品给客户端使用。 代理接收客户端的请求并进行一些处理 （访问控制和缓存等）， 然后再将请求传递给服务对象。
* The Subject interface declares common operations for both RealSubject and the
* Proxy. As long as the client works with RealSubject using this interface,
* you'll be able to pass it a proxy instead of a real subject.
*/
interface DuSubject {
/**
*
* @param du
*/
request(du:string): string; //void 也可以是方法，也可以是返回字符串等数据类型
}
/**
* The RealSubject contains some core business logic. Usually, RealSubjects are
* capable of doing some useful work which may also be very slow or sensitive -
* e.g. correcting input data. A Proxy can solve these issues without any
* changes to the RealSubject's code.
*/
class RealSubject implements DuSubject {
/**
*
* @param du
* @returns
*/
public request(du:string): string { //void
console.log('RealSubject: Handling request.');
return "RealSubject: Handling request."+du;
}
}
/**
* The Proxy has an interface identical to the RealSubject.
*/
class DuProxy implements DuSubject {
private realSubject: RealSubject;
/**
* The Proxy maintains a reference to an object of the RealSubject class. It
* can be either lazy-loaded or passed to the Proxy by the client.
*/
constructor(realSubject: RealSubject) {
this.realSubject = realSubject;
}
/**
* The most common applications of the Proxy pattern are lazy loading,
* caching, controlling the access, logging, etc. A Proxy can perform one of
* these things and then, depending on the result, pass the execution to the
* same method in a linked RealSubject object.
* @param du
*/
public request(du:string):string { //void
let str="";
if (this.checkAccess()) {
str=this.realSubject.request(du);
this.logAccess();
}
return str;
}
private checkAccess(): boolean {
// Some real checks should go here.
console.log('Proxy: Checking access prior to firing a real request.');
return true;
}
private logAccess(): void {
console.log('Proxy: Logging the time of request.');
}
}
/**
* The client code is supposed to work with all objects (both subjects and
* proxies) via the Subject interface in order to support both real subjects and
* proxies. In real life, however, clients mostly work with their real subjects
* directly. In this case, to implement the pattern more easily, you can extend
* your proxy from the real subject's class.
* @param subject
* @param du
*/
function clientCodeProxy(subject: DuSubject,du:string) {
// ...
return subject.request(du);
// ...
}
let pubpr1="";
let pubpr2="";
let pubpr3="Geovin Du";
let pubpr4="geovindu";
console.log('Client: Executing the client code with a real subject:');
const realSubject = new RealSubject();
pubpr1=clientCodeProxy(realSubject,pubpr4);
console.log('');
console.log('Client: Executing the same client code with a proxy:');
const proxy = new DuProxy(realSubject);
pubpr2=clientCodeProxy(proxy,pubpr3);
let messageProxy: string = 'Hello World,This is a typescript!,涂聚文 Geovin Du.Web';
document.body.innerHTML = messageProxy+",<br/>one="+pubpr1+",<br/>two="+pubpr2+",<br/>thee="+pubpr3+",<br/>four="+pubpr4+",<br/>TypeScript Proxy Pattern 代理模式";
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 Proxy Pattern 代理模式</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>
// require("./dist/geovin.js");
</script>
<script src="dist/Proxyts.js">
//
//type="module"
</script>
</body>
</html>
输出：
