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<?php
/**
* @version $Id$
* @package Koowa_Object
* @copyright Copyright (C) 2007 - 2012 Johan Janssens. All rights reserved.
* @license GNU GPLv3 <http://www.gnu.org/licenses/gpl.html>
* @link http://www.nooku.org
*/
/**
* Object Queue Class
*
* KObjectQueue is a type of container adaptor implemeneted as a double linked list
* and specifically designed such that its first element is always the greatest of
* the elements it contains based on the priority of the element.
*
* @author Johan Janssens <johan@nooku.org>
* @category Koowa
* @package Koowa_Object
* @see http://www.php.net/manual/en/class.splpriorityqueue.php
*/
class KObjectQueue extends KObject implements Iterator, Countable
{
/**
* Object list
*
* @var array
*/
protected $_object_list = null;
/**
* Priority list
*
* @var array
*/
protected $_priority_list = null;
/**
* Constructor
*
* @return void
*/
public function __construct(KConfig $config = null)
{
//If no config is passed create it
if(!isset($config)) $config = new KConfig();
parent::__construct($config);
$this->_object_list = new ArrayObject();
$this->_priority_list = new ArrayObject();
}
/**
* Inserts an object to the queue.
*
* @param object A KObject instance
* @param integer The associated priority
* @return boolean TRUE on success FALSE on failure
*/
public function enqueue( KObjectHandlable $object, $priority)
{
$result = false;
if($handle = $object->getHandle())
{
$this->_object_list->offsetSet($handle, $object);
$this->_priority_list->offsetSet($handle, $priority);
$this->_priority_list->asort();
$result = true;
}
return $result;
}
/**
* Removes an object from the queue
*
* @param object A KObject instance
* @return boolean TRUE on success FALSE on failure
*/
public function dequeue( KObjectHandlable $object)
{
$result = false;
if($handle = $object->getHandle())
{
if($this->_object_list->offsetExists($handle))
{
$this->_object_list->offsetUnset($handle);
$this->_priority_list->offsetUnSet($handle);
$result = true;
}
}
return $result;
}
/**
* Set the priority of an object in the queue
*
* @param object A KCommand object
* @param integer The priority
* @return KCommandChain
*/
public function setPriority(KObjectHandlable $object, $priority)
{
if($handle = $object->getHandle())
{
if($this->_priority_list->offsetExists($handle)) {
$this->_priority_list->offsetSet($handle, $priority);
$this->_priority_list->asort();
}
}
return $this;
}
/**
* Get the priority of an object in the queue
*
* @param object A KObject instance
* @return integer|false The command priority or FALSE if the commnand isn't enqueued
*/
public function getPriority(KObjectHandlable $object)
{
$result = false;
if($handle = $object->getHandle())
{
if($this->_priority_list->offsetExists($handle)) {
$result = $this->_priority_list->offsetGet($handle);
}
}
return $result;
}
/**
* Check if the queue has an item with the given priority
*
* @param int The priority to search for
* @return boolean
*/
public function hasPriority($priority)
{
$result = array_search($priority, $this->_priority_list);
return $result;
}
/**
* Check if the queue Does contain a given object
*
* @param mixed $datum
* @return bool
*/
public function contains(KObjectHandlable $object)
{
$result = false;
if($handle = $object->getHandle()) {
$result = $this->_object_list->offsetExists($handle);
}
return $result;
}
/**
* Returns the number of elements in the queue
*
* Required by the Countable interface
*
* @return int
*/
public function count()
{
return count($this->_object_list);
}
/**
* Rewind the Iterator to the top
*
* Required by the Iterator interface
*
* @return object KObjectQueue
*/
public function rewind()
{
reset($this->_object_list);
reset($this->_priority_list);
return $this;
}
/**
* Check whether the queue contains more object
*
* Required by the Iterator interface
*
* @return boolean
*/
public function valid()
{
return !is_null(key($this->_priority_list));
}
/**
* Return current object index
*
* Required by the Iterator interface
*
* @return scalar
*/
public function key()
{
return key($this->_priority_list);
}
/**
* Return current object pointed by the iterator
*
* Required by the Iterator interface
*
* @return mixed
*/
public function current()
{
return $this->_object_list[$this->key()];
}
/**
* Move to the next object
*
* Required by the Iterator interface
*
* @return void
*/
public function next()
{
return next($this->_priority_list);
}
/**
* Return the object from the top of the queue
*
* @return KObject or NULL is queue is empty
*/
public function top()
{
$handles = array_keys((array)$this->_priority_list);
$object = null;
if(isset($handles[0])) {
$object = $this->_object_list[$handles[0]];
}
return $object;
}
/**
* Checks whether the queue is empty
*
* @return boolean
*/
public function isEmpty()
{
return !count($this->_object_list);
}
/**
* Preform a deep clone of the object
*
* @retun void
*/
public function __clone()
{
parent::__clone();
$this->_object_list = clone $this->_object_list;
$this->_priority_list = clone $this->_priority_list;
}
}
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