PHP callback steps

PHP callback method callback. you don't need to explain it. let's take a look at how PHP implements callback 1. create an object classProduct {& nbsp; public $ name; // callback method of & nbsp; function _ const PHP for convenience testing
Callback. let's take a look at how PHP implements callback.

1. first create an object
Class Product {
Public $ name; // to facilitate testing

Function _ construct ($ name ){
$ This-> name = $ name;
}
}

2. use callback
Class ProcessSale {
Private $ callbacks;

// Set the callback method
Function registerCallBack ($ callback ){
If (! Is_callable ($ callback )){
Throw new Exception ("xxxxxx ");
}

$ This-> callbacks [] = $ callback;
}

Function sale ($ product ){
Print "{$ product-> name}: processing \ n ";

Foreach ($ this-> callbacks as $ callback ){
Call_user_func ($ callback, $ product );
}
}
}

3. test
$ Logger = function ($ product ){
Print "logging ({$ product-> name })";
}

$ Processor = new ProcessSale ();
$ Processor-> registerCallBack ($ logger );

$ Processor-> sale (new Product ("test "));