* @author Dan Scott * @copyright 2003-2008 Oy Realnode Ab, Dan Scott * @license http://www.gnu.org/copyleft/lesser.html LGPL License 2.1 * @version CVS: $Id$ * @link http://pear.php.net/package/File_MARC */ // {{{ class File_MARC_List extends Structures_LinkedList_Double /** * The File_MARC_List class extends the Structures_LinkedList_Double class * to override the key() method in a meaningful way for foreach() iterators. * * For the list of {@link File_MARC_Field} objects in a {@link File_MARC_Record} * object, the key() method returns the tag name of the field. * * For the list of {@link File_MARC_Subfield} objects in a {@link * File_MARC_Data_Field} object, the key() method returns the code of * the subfield. * *


 * // Iterate through the fields in a record with key=>value iteration
 * foreach ($record->getFields() as $tag=>$value) {
 *     print "$tag: ";
 *     if ($value instanceof File_MARC_Control_Field) {
 *         print $value->getData();
 *     }
 *     else {
 *         // Iterate through the subfields in this data field
 *         foreach ($value->getSubfields() as $code=>$subdata) {
 *             print "_$code";
 *         }
 *     }
 *     print "\n";
 * }
 *

* * @category File_Formats * @package File_MARC * @author Dan Scott * @license http://www.gnu.org/copyleft/lesser.html LGPL License 2.1 * @link http://pear.php.net/package/File_MARC */ class File_MARC_List extends Structures_LinkedList_Double { // {{{ key() /** * Returns the tag for a {@link File_MARC_Field} object, or the code * for a {@link File_MARC_Subfield} object. * * This method enables you to use a foreach iterator to retrieve * the tag or code as the key for the iterator. * * @return string returns the tag or code */ function key() { if ($this->current() instanceof File_MARC_Field) { return $this->current()->getTag(); } elseif ($this->current() instanceof File_MARC_Subfield) { return $this->current()->getCode(); } return false; } // }}} } // }}}