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Diffstat (limited to 'framework/collections/CQueue.php')
| -rw-r--r-- | framework/collections/CQueue.php | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/framework/collections/CQueue.php b/framework/collections/CQueue.php new file mode 100644 index 0000000..9f1aa99 --- /dev/null +++ b/framework/collections/CQueue.php @@ -0,0 +1,172 @@ +<?php +/** + * This file contains classes implementing the queue feature. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @link http://www.yiiframework.com/ + * @copyright Copyright © 2008-2011 Yii Software LLC + * @license http://www.yiiframework.com/license/ + */ + +/** + * CQueue implements a queue. + * + * The typical queue operations are implemented, which include + * {@link enqueue()}, {@link dequeue()} and {@link peek()}. In addition, + * {@link contains()} can be used to check if an item is contained + * in the queue. To obtain the number of the items in the queue, + * check the {@link getCount Count} property. + * + * Items in the queue may be traversed using foreach as follows, + * <pre> + * foreach($queue as $item) ... + * </pre> + * + * @property Iterator $iterator An iterator for traversing the items in the queue. + * @property integer $count The number of items in the queue. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @version $Id: CQueue.php 3427 2011-10-25 00:03:52Z alexander.makarow $ + * @package system.collections + * @since 1.0 + */ +class CQueue extends CComponent implements IteratorAggregate,Countable +{ + /** + * internal data storage + * @var array + */ + private $_d=array(); + /** + * number of items + * @var integer + */ + private $_c=0; + + /** + * Constructor. + * Initializes the queue with an array or an iterable object. + * @param array $data the intial data. Default is null, meaning no initialization. + * @throws CException If data is not null and neither an array nor an iterator. + */ + public function __construct($data=null) + { + if($data!==null) + $this->copyFrom($data); + } + + /** + * @return array the list of items in queue + */ + public function toArray() + { + return $this->_d; + } + + /** + * Copies iterable data into the queue. + * Note, existing data in the list will be cleared first. + * @param mixed $data the data to be copied from, must be an array or object implementing Traversable + * @throws CException If data is neither an array nor a Traversable. + */ + public function copyFrom($data) + { + if(is_array($data) || ($data instanceof Traversable)) + { + $this->clear(); + foreach($data as $item) + { + $this->_d[]=$item; + ++$this->_c; + } + } + else if($data!==null) + throw new CException(Yii::t('yii','Queue data must be an array or an object implementing Traversable.')); + } + + /** + * Removes all items in the queue. + */ + public function clear() + { + $this->_c=0; + $this->_d=array(); + } + + /** + * @param mixed $item the item + * @return boolean whether the queue contains the item + */ + public function contains($item) + { + return array_search($item,$this->_d,true)!==false; + } + + /** + * Returns the item at the top of the queue. + * @return mixed item at the top of the queue + * @throws CException if the queue is empty + */ + public function peek() + { + if($this->_c===0) + throw new CException(Yii::t('yii','The queue is empty.')); + else + return $this->_d[0]; + } + + /** + * Removes and returns the object at the beginning of the queue. + * @return mixed the item at the beginning of the queue + * @throws CException if the queue is empty + */ + public function dequeue() + { + if($this->_c===0) + throw new CException(Yii::t('yii','The queue is empty.')); + else + { + --$this->_c; + return array_shift($this->_d); + } + } + + /** + * Adds an object to the end of the queue. + * @param mixed $item the item to be appended into the queue + */ + public function enqueue($item) + { + ++$this->_c; + array_push($this->_d,$item); + } + + /** + * Returns an iterator for traversing the items in the queue. + * This method is required by the interface IteratorAggregate. + * @return Iterator an iterator for traversing the items in the queue. + */ + public function getIterator() + { + return new CQueueIterator($this->_d); + } + + /** + * Returns the number of items in the queue. + * @return integer the number of items in the queue + */ + public function getCount() + { + return $this->_c; + } + + /** + * Returns the number of items in the queue. + * This method is required by Countable interface. + * @return integer number of items in the queue. + */ + public function count() + { + return $this->getCount(); + } +} |