PHP5.3_延遲靜態繫結_static

From : http://my.oschina.net/liuhui1990/blog/38611

基於PHP版本: 5.3.5

PHP5.3 以後引入了延遲靜態繫結:

static(關鍵字) 類似於 self(關鍵字) , 但它指向的是被調用的類(Document) 而不是包含類(DomainObject), static 和 self 的區別:

<?phpclass DomainObject{    public static function createStatic(){        return new static();            }    public static function createSelf(){        return new self();    }}class User extends DomainObject{    }class Document extends DomainObject{    }echo '<pre>';var_dump( Document::createStatic());var_dump( Document::createSelf());

Result :

object(Document)[1]object(DomainObject)[1]

以前你這麼寫:

abstract class DomainObject{}class User extends DomainObject{    public static function create(){        return new User();    }}class Document extends DomainObject{    public static function create(){        return new Document();    }}

現在, 你可以這麼寫: 

abstract class DomainObject{    public static function create(){        return new static();    }}class User extends DomainObject{}class Document extends DomainObject{}

好處: 可以節省大量重複代碼~