[Sommaire] [Imprimer]

   1  <?php
   2  /*
   3   *  $Id: ResultSetIterator.php,v 1.3 2004/03/15 17:47:45 hlellelid Exp $
   4   *
   5   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   6   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   7   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   8   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   9   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  10   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  11   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  12   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  13   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  14   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  15   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  16   *
  17   * This software consists of voluntary contributions made by many individuals
  18   * and is licensed under the LGPL. For more information please see
  19   * <http://creole.phpdb.org>.
  20   */
  21  
  22  /**
  23   * Basic ResultSet Iterator.
  24   * 
  25   * This can be returned by your class's getIterator() method, but of course
  26   * you can also implement your own (e.g. to get better performance, by using direct
  27   * driver calls and avoiding other side-effects inherent in ResultSet scrolling
  28   * functions -- e.g. beforeFirst() / afterLast(), etc.).
  29   *
  30   * Important: ResultSet iteration does rewind the resultset if it is not at the
  31   * start.  Not all drivers support reverse scrolling, so this may result in an
  32   * exception in some cases (Oracle).
  33   * 
  34   * Developer note:
  35   * The implementation of this class is a little weird because it fetches the
  36   * array _early_ in order to answer valid() w/o needing to know total num
  37   * of fields.  Remember the way iterators work:
  38   * <code>
  39   * $it = $obj->getIterator();
  40   * for($it->rewind(); $it->valid(); $it->next()) {
  41   *  $key = $it->current();
  42   *  $val = $it->key();
  43   *  echo "$key = $val\n";
  44   * }
  45   * unset($it);
  46   * </code>
  47   * 
  48   * @author    Hans Lellelid <hans@xmpl.org>
  49   * @version   $Revision: 1.3 $
  50   * @package   creole
  51   */
  52  class ResultSetIterator implements Iterator {
  53  
  54      private $rs;    
  55      
  56      /**
  57       * Construct the iterator.
  58       * @param ResultSet $rs
  59       */
  60      public function __construct(ResultSet $rs)
  61      {
  62          $this->rs = $rs;
  63      }
  64      
  65      /**
  66       * If not at start of resultset, this method will call seek(0).
  67       * @see ResultSet::seek()
  68       */
  69      function rewind()
  70      {
  71          if (!$this->rs->isBeforeFirst()) {
  72              $this->rs->seek(0);
  73          }
  74      }
  75      
  76      /**
  77       * This method checks to see whether there are more results
  78       * by advancing the cursor position.
  79       * @see ResultSet::next()
  80       */
  81      function valid()
  82      {
  83          return $this->rs->next();
  84      }
  85      
  86      /**
  87       * Returns the cursor position.
  88       * @return int
  89       */
  90      function key()
  91      {
  92          return $this->rs->getCursorPos();
  93      }
  94      
  95      /**
  96       * Returns the row (assoc array) at current cursor pos.
  97       * @return array
  98       */
  99      function current()
 100      {
 101         return $this->rs->getRow();
 102      }
 103      
 104      /**
 105       * This method does not actually do anything since we have already advanced
 106       * the cursor pos in valid().
 107       * @see valid()
 108       */
 109      function next()
 110      {
 111      }
 112  
 113  }