JavaScript design pattern-Simple Factory Model example---XHR factory

The first step, the Ajax Operation interface (the purpose is to play an interface detection function)

(1) Introduction of interface file

//define a static method to implement direct validation of interfaces and implementation classes//static method do not write Interface.prototype, because this is written to the interface of the prototype chain//We're going to write the static function directly to the class level .//(1) Define an interface classvarInterface=function (name,methods) {//Name : Interface name    if(arguments.length<2) {alert ("must be a two parameter")    }     This. name=name;  This. methods=[];//defines an empty array load function name     for(varI=0; i<methods.length;i++){        if(typeofmethods[i]!="string") {alert ("function Name must be a string type"); }Else {             This. Methods.push (Methods[i]); }}};interface.ensureimplement=function (Object) {    if(arguments.length<2){        Throw  NewError ("parameters must be no less than 2")        return false; }     for(varI=1; i<arguments.length;i++){        varInter=Arguments[i]; //if it is an interface, it must be a interface type .        if(inter.constructor!=Interface) {            Throw  NewError ("if it is an interface class, it must be a interface type."); }        //determine whether the methods in the interface are all implemented//Traversal Function Collection         for(varj=0; j<inter.methods.length;j++){            varMETHOD=INTER.METHODS[J];//all functions in the interface//Object[method] passed in function//The final decision is whether the incoming function matches the function used in the interface.            if(!Object[method]| |typeof Object[method]!="function"){//The implementation class must have a method name that is the same as the method name used in the interface                Throw  NewError ("all methods in the interface are not fully implemented in the implementation class")            }        }    }}

The second step is to instantiate a specific Ajax interface

var ajaxhandler=New Interface ("ajaxhandler", ["request" ,"createxhrobject"]);

The third step, the Ajax implementation class for the interface

(1) Define an empty class

  var   Simplehandler=function () {};

(2) Extending the prototype directly on the empty class---Implement the method inside the interface

Simplehandler.prototype={        /** method:get post * URL: Request Address * Callback: callback function * Postvars: Incoming parameter **/request:function (method,url,callback,postvars) {//1, use factory to get XHR object            varXhr= This. Createxhrobject (); Xhr.onreadystatechange=function () {//4 means the interaction is complete.                if(xhr.readystate!=4)return; //a value of 200 is normal interaction completion//404 File Not Found//500 Internal Program error(xhr.status== $)?callback.success (xhr.responsetext,xhr.responsexml): Callback.failure (Xhr.status); }            //Open LinkXhr.open (Method,url,true); //Setting Parameters            if(method!="POST") {Postvars=NULL;        } xhr.send (Postvars); },        //2, Get Xhr Method--different browser not the samecreatexhrobject:function () {varmethods=[function () {return NewXMLHttpRequest ();}, function () {return NewActiveXObject ("Microsoft.XMLHTTP");}          ]; //using Try--catch to make an intelligent loop body                      for(varI=0; i<methods.length;i++){                          Try{methods[i] (); }Catch(e) {Continue;//back to where the loop started.                          }                          This. Createxhrobject=methods[i] ();//It is important to ensure that the full-loop array is not used for every request                          returnMethods[i] (); }            //If all is wrong then error            Throw  NewError ("Error"); }    };

The third step, the use of inspection

(1) Instantiating an object

  var myhandler=New simplehandler ();

(2) interface verifies that the implementation class is fully implemented in the interface method

  Interface.ensureimplement (Myhandler,ajaxhandler); // Verify that all methods in the interface are implemented

(3) Define a callback object

   var callback={        success:function (responsetext) {            alert ("OK"          },         failure:function (status) {            alert (status+failure " )            }        };

(4) Final use format

   Myhandler.request ("POST","http://www.baidu.com", callback ); //If The URL is "" will default to local links, other correct links, there will be cross-domain issues

JavaScript design pattern-Simple Factory Model example---XHR factory