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    SplSubject::attach

    (PHP 5 >= 5.1.0, PHP 7, PHP 8)

    SplSubject::attach — SplObserver をアタッチする

    説明

    public SplSubject::attach(SplObserver $observer): void

    SplObserver にアタッチし、更新を通知できるようにします。

    警告

    この関数は、 現在のところ詳細な情報はありません。引数のリストのみが 記述されています。

    パラメータ

    observer

    アタッチする SplObserver。

    戻り値

    値を返しません。

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    User Contributed Notes 2 notes

    up
    2
    workspace dot development at yahoo dot com
    13 years ago
    i think that Observer pattern is always implemented as "static" to be called from any scope, for example:
    <?php
    class Observer {
    //attach here the caller's scope
    private static $stackTrace = array( );
    public static function     wasTriggeredOnce() {
    //...if is not in the stack, then:
    self::$stackTrace[] = max( debug_backtrace( ) );
    }
    }

    class     YourFramework {

    public function     launchPlatform() {

    //could not let user to launch application twice!
    Observer::wasTriggeredOnce();
    }
    }
    //cause is static
    Observer::hereIsnoNeedToInstantiateAgain();
    ?>
    up
    1
    goran
    13 years ago
    The most obvious storage type for observers (stored in attach()) is array. In order to be able to detach attached objects, you should be able to identify it inside observer storage.

    I suggest you attach observers this way:

    $this->_observers[spl_object_hash($observer)] = $observer;

    so you can detach it later if you need:

    unset($this->_observers[spl_object_hash($observer)]);
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