Recommended way to set a variable only once in PHP -

the use case follows: have variable $roles need run db query set value. of methods in class need $roles , don't need it, instantiate in constructor not option.

the question elegant way set value once methods need variable won't need check if value set , use right away.

i thought 2 options accomplish it, both of them don't feel natural.

option 1 (more procedural way):

class dosomething {     public function getroles() {         static $roles;         if (!isset($roles)) {             $roles = do_query_to_the_db_and_give_me_the_roles();         }         return $roles;     }      public function dox() {         $roles = $this->getroles();     } } 

option 2: (more oop way)

class dosomething {     private $roles;      public function setroles() {         $this->roles = do_query_to_the_db_and_give_me_the_roles();     }      public function getroles() {         if (!isset($this->roles)) {             $this->setroles();         }         return $this->roles;     }      public function dox() {         $roles = $this->getroles();     } } 

i'm more happy hear other approaches. thanks.

either way fine. if you're worried performance cache roles via memcache time period , refresh often.