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libraries/joomla/database/iterator.php

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+<?php
+/**
+ * @package     Joomla.Platform
+ * @subpackage  Database
+ *
+ * @copyright   Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
+ * @license     GNU General Public License version 2 or later; see LICENSE
+ */
+
+defined('JPATH_PLATFORM') or die;
+
+/**
+ * Joomla Platform Database Driver Class
+ *
+ * @package     Joomla.Platform
+ * @subpackage  Database
+ * @since       12.1
+ */
+abstract class JDatabaseIterator implements Countable, Iterator
+{
+	/**
+	 * The database cursor.
+	 *
+	 * @var    mixed
+	 * @since  12.1
+	 */
+	protected $cursor;
+
+	/**
+	 * The class of object to create.
+	 *
+	 * @var    string
+	 * @since  12.1
+	 */
+	protected $class;
+
+	/**
+	 * The name of the column to use for the key of the database record.
+	 *
+	 * @var    mixed
+	 * @since  12.1
+	 */
+	private $_column;
+
+	/**
+	 * The current database record.
+	 *
+	 * @var    mixed
+	 * @since  12.1
+	 */
+	private $_current;
+
+	/**
+	 * A numeric or string key for the current database record.
+	 *
+	 * @var    scalar
+	 * @since  12.1
+	 */
+	private $_key;
+
+	/**
+	 * The number of fetched records.
+	 *
+	 * @var    integer
+	 * @since  12.1
+	 */
+	private $_fetched = 0;
+
+	/**
+	 * Database iterator constructor.
+	 *
+	 * @param   mixed   $cursor  The database cursor.
+	 * @param   string  $column  An option column to use as the iterator key.
+	 * @param   string  $class   The class of object that is returned.
+	 *
+	 * @throws  InvalidArgumentException
+	 */
+	public function __construct($cursor, $column = null, $class = 'stdClass')
+	{
+		if (!class_exists($class))
+		{
+			throw new InvalidArgumentException(sprintf('new %s(*%s*, cursor)', get_class($this), gettype($class)));
+		}
+
+		$this->cursor = $cursor;
+		$this->class = $class;
+		$this->_column = $column;
+		$this->_fetched = 0;
+		$this->next();
+	}
+
+	/**
+	 * Database iterator destructor.
+	 *
+	 * @since   12.1
+	 */
+	public function __destruct()
+	{
+		if ($this->cursor)
+		{
+			$this->freeResult($this->cursor);
+		}
+	}
+
+	/**
+	 * The current element in the iterator.
+	 *
+	 * @return  object
+	 *
+	 * @see     Iterator::current()
+	 * @since   12.1
+	 */
+	public function current()
+	{
+		return $this->_current;
+	}
+
+	/**
+	 * The key of the current element in the iterator.
+	 *
+	 * @return  scalar
+	 *
+	 * @see     Iterator::key()
+	 * @since   12.1
+	 */
+	public function key()
+	{
+		return $this->_key;
+	}
+
+	/**
+	 * Moves forward to the next result from the SQL query.
+	 *
+	 * @return  void
+	 *
+	 * @see     Iterator::next()
+	 * @since   12.1
+	 */
+	public function next()
+	{
+		// Set the default key as being the number of fetched object
+		$this->_key = $this->_fetched;
+
+		// Try to get an object
+		$this->_current = $this->fetchObject();
+
+		// If an object has been found
+		if ($this->_current)
+		{
+			// Set the key as being the indexed column (if it exists)
+			if (isset($this->_current->{$this->_column}))
+			{
+				$this->_key = $this->_current->{$this->_column};
+			}
+
+			// Update the number of fetched object
+			$this->_fetched++;
+		}
+	}
+
+	/**
+	 * Rewinds the iterator.
+	 *
+	 * This iterator cannot be rewound.
+	 *
+	 * @return  void
+	 *
+	 * @see     Iterator::rewind()
+	 * @since   12.1
+	 */
+	public function rewind()
+	{
+	}
+
+	/**
+	 * Checks if the current position of the iterator is valid.
+	 *
+	 * @return  boolean
+	 *
+	 * @see     Iterator::valid()
+	 * @since   12.1
+	 */
+	public function valid()
+	{
+		return (boolean) $this->_current;
+	}
+
+	/**
+	 * Method to fetch a row from the result set cursor as an object.
+	 *
+	 * @return  mixed  Either the next row from the result set or false if there are no more rows.
+	 *
+	 * @since   12.1
+	 */
+	abstract protected function fetchObject();
+
+	/**
+	 * Method to free up the memory used for the result set.
+	 *
+	 * @return  void
+	 *
+	 * @since   12.1
+	 */
+	abstract protected function freeResult();
+}