Weakref::acquire

例1 Weakref::acquire() の例
 

class MyClass {
    public function __destruct() {
        echo "Destroying object!\n";
    }
}

$o1 = new MyClass;

$r1 = new Weakref($o1);

$r1->acquire();

echo "Unsetting o1...\n";
unset($o1);

$o2 = $r1->get();

$r1->release();

echo "Unsetting o2...\n";
unset($o2);

 
上の例の出力は以下となります。
 
Unsetting o1...
Unsetting o2...
Destroying object!
 
例2 ネストした確保と解放の例
 

class MyClass {
    public function __destruct() {
        echo "Destroying object!\n";
    }
}

$o1 = new MyClass;

$r1 = new Weakref($o1);

echo "Acquiring...\n";
$r1->acquire();

echo "  Unsetting...\n";
unset($o1);

echo "  Acquiring...\n";
$r1->acquire();

echo "    Acquiring...\n";
$r1->acquire();

echo "    Releasing...\n";
$r1->release();

echo "  Releasing...\n";
$r1->release();

echo "Releasing...\n";
$r1->release();


 
上の例の出力は以下となります。
 
Acquiring...
  Unsetting...
  Acquiring...
    Acquiring...
    Releasing...
  Releasing...
Releasing...
Destroying object!