The responsibility chain pattern of common design pattern and its implementation in PHP

The responsibility chain pattern is a behavioral pattern, which contains some command objects and a series of processing objects. Each processing object determines which command objects it can handle, and it knows how to pass a Command object that it cannot handle to the next processing object in the chain. The pattern also describes how to add a new processing object to the end of the processing chain.

Main role

Abstract responsibility (Responsibility) Role: Defines public methods that are supported by all responsibilities.

Specific responsibilities (concrete Responsibility) Role: specific responsibilities implemented with abstract responsibility interfaces

Responsibility chain (Chain of responsibility) role: Set call rules for responsibility

Class diagram

Instance

<?phpabstract class Responsibility {//abstract responsibility role    protected $next;//Next Responsibility Role public     function Setnext ( Responsibility $l) {        $this->next = $l;        return $this;    }    Abstract public function operate (); Action method} class Responsibilitya extends Responsibility {public    function __construct () {} public    function operate ( {        if (false = = Is_null ($this->next)) {            $this->next->operate ();        }    };} Class Responsibilityb extends Responsibility {public    function __construct () {} public    function operate () { C14/>if (False = = Is_null ($this->next)) {            $this->next->operate ();        }    };} $res _a = new Responsibilitya (); $res _b = new Responsibilityb (); $res _a->setnext ($res _b);? >

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