PHP中迭代器的简单实现及Yii框架中的迭代器实现

/
 Iterator模式的简单实现类
/
class sample implements Iterator {
  private $_items ;
 
  public function __construct(&$data) {
    $this->_items = $data;
  }
  public function current() {
    return current($this->_items);
  }
 
  public function next() {
    next($this->_items);  
  }
 
  public function key() {
    return key($this->_items);
  }
 
  public function rewind() {
    reset($this->_items);
  }
 
  public function valid() {
    return ($this->current() !== FALSE);
  }
}
 
/ DEMO /
$data = array(1, 2, 3, 4, 5);
$sa = new sample($data);
foreach ($sa AS $key => $row) {
  echo $key, ' ', $row, '<br />';
}

abstract public void Iterator::next ( void )

$data = array('0' => 11, "" => 22, 's3' => 33, 0, 0, "", false, 0, 1);

class CMapIterator implements Iterator {
/
 @var array the data to be iterated through
/
  private $_d;
/
 @var array list of keys in the map
/
  private $_keys;
/
 @var mixed current key
/
  private $_key;
 
/
 Constructor.
 @param array the data to be iterated through
/
  public function __construct(&$data) {
    $this->_d=&$data;
    $this->_keys=array_keys($data);
  }
 
/
 Rewinds internal array pointer.
 This method is required by the interface Iterator.
/
  public function rewind() {                                         
    $this->_key=reset($this->_keys);
  }
 
/
 Returns the key of the current array element.
 This method is required by the interface Iterator.
 @return mixed the key of the current array element
/
  public function key() {
    return $this->_key;
  }
 
/
 Returns the current array element.
 This method is required by the interface Iterator.
 @return mixed the current array element
/
  public function current() {
    return $this->_d[$this->_key];
  }
 
/
 Moves the internal pointer to the next array element.
 This method is required by the interface Iterator.
/
  public function next() {
    $this->_key=next($this->_keys);
  }
 
/
 Returns whether there is an element at current position.
 This method is required by the interface Iterator.
 @return boolean
/
  public function valid() {
    return $this->_key!==false;
  }
}
 
$data = array('s1' => 11, 's2' => 22, 's3' => 33);
$it = new CMapIterator($data);
foreach ($it as $row) {
  echo $row, '<br />';
}