PHP應用
if($class instanceof Traversable) {
  //foreach
}

PHP應用
Iterator extends Traversable 
{ 
  //返回當前索引游標指向的元素 
  abstract public mixed current(void) 
  //返回當前索引游標指向的元素的鍵名 
  abstract public scalar key(void) 
  //移動當前索引游標指向下一元素 
  abstract public void next(void) 
  //重置索引游標的指向第一個元素 
  abstract public void rewind(void) 
  //判斷當前索引游標指向的是否是一個元素,常常在調用 rewind()或 next()使用 
  abstract public boolean valid(void) 
} 

PHP應用
class myIterator implements Iterator {
  private $position = 0 ;
  private $array = array(
    "firstelement" ,
    "secondelement" ,
    "lastelement" ,
  );
 
  public function __construct () {
    $this -> position = 0 ;
  }
 
  function rewind () {
    var_dump ( __METHOD__ );
    $this -> position = 0 ;
  }
 
  function current () {
    var_dump ( __METHOD__ );
    return $this -> array [ $this -> position ];
  }
 
  function key () {
    var_dump ( __METHOD__ );
    return $this -> position ;
  }
 
  function next () {
    var_dump ( __METHOD__ );
    ++ $this -> position ;
  }
 
  function valid () {
    var_dump ( __METHOD__ );
    return isset( $this -> array [ $this -> position ]);
  }
}
 
$it = new myIterator ;
 
foreach( $it as $key => $value ) {
  var_dump ( $key , $value );
  echo "\n" ;
}

PHP應用
IteratorAggregate extends Traversable {
 
//獲取外部迭代器
abstract public Traversable getIterator ( void )
} 

PHP應用
class myData implements IteratorAggregate {
  public $property1 = "Public property one" ;
  public $property2 = "Public property two" ;
  public $property3 = "Public property three" ;
 
  public function __construct () {
    $this -> property4 = "last property" ;
  }
 
  
  public function getIterator () {
    return new ArrayIterator ( $this );
  }
}
 
$obj = new myData ;
 
foreach( $obj as $key => $value ) {
  var_dump ( $key , $value );
  echo "\n" ;
}

PHP應用
ArrayAccess {
  /* 方法 */
  abstract public boolean offsetExists ( mixed $offset ) //檢查偏移位置是否存在
  abstract public mixed offsetGet ( mixed $offset ) //獲取一個偏移位置的值
  abstract public void offsetSet ( mixed $offset , mixed $value ) //設置一個偏移位置的值
  abstract public void offsetUnset ( mixed $offset ) //復位一個偏移位置的值
}

PHP應用
class obj implements arrayaccess {
  private $container = array();
  public function __construct () {
    $this -> container = array(
      "one"  => 1 ,
      "two"  => 2 ,
      "three" => 3 ,
    );
  }
  public function offsetSet ( $offset , $value ) {
    if ( is_null ( $offset )) {
      $this -> container [] = $value ;
    } else {
      $this -> container [ $offset ] = $value ;
    }
  }
  public function offsetExists ( $offset ) {
    return isset( $this -> container [ $offset ]);
  }
  public function offsetUnset ( $offset ) {
    unset( $this -> container [ $offset ]);
  }
  public function offsetGet ( $offset ) {
    return isset( $this -> container [ $offset ]) ? $this -> container [ $offset ] : null ;
  }
}
 
$obj = new obj ;
 
var_dump (isset( $obj [ "two" ]));
var_dump ( $obj [ "two" ]);
unset( $obj [ "two" ]);
var_dump (isset( $obj [ "two" ]));
$obj [ "two" ] = "A value" ;
var_dump ( $obj [ "two" ]);
$obj [] = 'Append 1' ;
$obj [] = 'Append 2' ;
$obj [] = 'Append 3' ;
print_r ( $obj );

PHP應用
Serializable {
 
  /* 辦法 */
  abstract public string serialize ( void ) //對象的字符串表示
  abstract public mixed unserialize ( string $serialized ) // 構造對象
}

PHP應用
class obj implements Serializable {
  private $data ;
  public function __construct () {
    $this -> data = "My private data" ;
  }
  public function serialize () {
    return serialize ( $this -> data );
  }
  public function unserialize ( $data ) {
    $this -> data = unserialize ( $data );
  }
  public function getData () {
    return $this -> data ;
  }
}
 
$obj = new obj ;
$ser = serialize ( $obj );
print_r($ser);
$newobj = unserialize ( $ser );
print_r($newobj);

PHP應用
Closure {
  /* 辦法 */
  __construct ( void ) //用于禁止實例化的構造函數
  public static Closure bind ( Closure $closure , object $newthis [, mixed $newscope = 'static' ] ) //復制一個閉包,綁定指定的$this對象和類作用域.
  public Closure bindTo ( object $newthis [, mixed $newscope = 'static' ] ) //復制當前閉包對象,綁定指定的$this對象和類作用域.
}

PHP應用
class A {
  private static $sfoo = 1 ;
  private $ifoo = 2 ;
}
 $cl1 = static function() {
  return A :: $sfoo ;
};
 $cl2 = function() {
  return $this -> ifoo ;
};
 
 $bcl1 = Closure :: bind ( $cl1 , null , 'A' );
 $bcl2 = Closure :: bind ( $cl2 , new A (), 'A' );
echo $bcl1 (), "\n" ;
echo $bcl2 (), "\n" ;