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-rw-r--r--framework/Collections/TList.php972
1 files changed, 486 insertions, 486 deletions
diff --git a/framework/Collections/TList.php b/framework/Collections/TList.php
index 1e4c439c..4ba4fb58 100644
--- a/framework/Collections/TList.php
+++ b/framework/Collections/TList.php
@@ -1,486 +1,486 @@
-<?php
-/**
- * TList, TListIterator classes
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @link http://www.pradosoft.com/
- * @copyright Copyright &copy; 2005-2012 PradoSoft
- * @license http://www.pradosoft.com/license/
- * @version $Id$
- * @package System.Collections
- */
-
-/**
- * TList class
- *
- * TList implements an integer-indexed collection class.
- *
- * You can access, append, insert, remove an item by using
- * {@link itemAt}, {@link add}, {@link insertAt}, {@link remove}, and {@link removeAt}.
- * To get the number of the items in the list, use {@link getCount}.
- * TList can also be used like a regular array as follows,
- * <code>
- * $list[]=$item; // append at the end
- * $list[$index]=$item; // $index must be between 0 and $list->Count
- * unset($list[$index]); // remove the item at $index
- * if(isset($list[$index])) // if the list has an item at $index
- * foreach($list as $index=>$item) // traverse each item in the list
- * $n=count($list); // returns the number of items in the list
- * </code>
- *
- * To extend TList by doing additional operations with each addition or removal
- * operation, override {@link insertAt()}, and {@link removeAt()}.
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @version $Id$
- * @package System.Collections
- * @since 3.0
- */
-class TList extends TComponent implements IteratorAggregate,ArrayAccess,Countable
-{
- /**
- * internal data storage
- * @var array
- */
- private $_d=array();
- /**
- * number of items
- * @var integer
- */
- private $_c=0;
- /**
- * @var boolean whether this list is read-only
- */
- private $_r=false;
-
- /**
- * Constructor.
- * Initializes the list with an array or an iterable object.
- * @param array|Iterator the initial data. Default is null, meaning no initialization.
- * @param boolean whether the list is read-only
- * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator.
- */
- public function __construct($data=null,$readOnly=false)
- {
- if($data!==null)
- $this->copyFrom($data);
- $this->setReadOnly($readOnly);
- }
-
- /**
- * @return boolean whether this list is read-only or not. Defaults to false.
- */
- public function getReadOnly()
- {
- return $this->_r;
- }
-
- /**
- * @param boolean whether this list is read-only or not
- */
- protected function setReadOnly($value)
- {
- $this->_r=TPropertyValue::ensureBoolean($value);
- }
-
- /**
- * Returns an iterator for traversing the items in the list.
- * This method is required by the interface IteratorAggregate.
- * @return Iterator an iterator for traversing the items in the list.
- */
- public function getIterator()
- {
- return new ArrayIterator( $this->_d );
- }
-
- /**
- * Returns the number of items in the list.
- * This method is required by Countable interface.
- * @return integer number of items in the list.
- */
- public function count()
- {
- return $this->getCount();
- }
-
- /**
- * @return integer the number of items in the list
- */
- public function getCount()
- {
- return $this->_c;
- }
-
- /**
- * Returns the item at the specified offset.
- * This method is exactly the same as {@link offsetGet}.
- * @param integer the index of the item
- * @return mixed the item at the index
- * @throws TInvalidDataValueException if the index is out of the range
- */
- public function itemAt($index)
- {
- if($index>=0 && $index<$this->_c)
- return $this->_d[$index];
- else
- throw new TInvalidDataValueException('list_index_invalid',$index);
- }
-
- /**
- * Appends an item at the end of the list.
- * @param mixed new item
- * @return integer the zero-based index at which the item is added
- * @throws TInvalidOperationException if the list is read-only
- */
- public function add($item)
- {
- $this->insertAt($this->_c,$item);
- return $this->_c-1;
- }
-
- /**
- * Inserts an item at the specified position.
- * Original item at the position and the next items
- * will be moved one step towards the end.
- * @param integer the specified position.
- * @param mixed new item
- * @throws TInvalidDataValueException If the index specified exceeds the bound
- * @throws TInvalidOperationException if the list is read-only
- */
- public function insertAt($index,$item)
- {
- if(!$this->_r)
- {
- if($index===$this->_c)
- $this->_d[$this->_c++]=$item;
- else if($index>=0 && $index<$this->_c)
- {
- array_splice($this->_d,$index,0,array($item));
- $this->_c++;
- }
- else
- throw new TInvalidDataValueException('list_index_invalid',$index);
- }
- else
- throw new TInvalidOperationException('list_readonly',get_class($this));
- }
-
- /**
- * Removes an item from the list.
- * The list will first search for the item.
- * The first item found will be removed from the list.
- * @param mixed the item to be removed.
- * @return integer the index at which the item is being removed
- * @throws TInvalidDataValueException If the item does not exist
- * @throws TInvalidOperationException if the list is read-only
- */
- public function remove($item)
- {
- if(!$this->_r)
- {
- if(($index=$this->indexOf($item))>=0)
- {
- $this->removeAt($index);
- return $index;
- }
- else
- throw new TInvalidDataValueException('list_item_inexistent');
- }
- else
- throw new TInvalidOperationException('list_readonly',get_class($this));
- }
-
- /**
- * Removes an item at the specified position.
- * @param integer the index of the item to be removed.
- * @return mixed the removed item.
- * @throws TInvalidDataValueException If the index specified exceeds the bound
- * @throws TInvalidOperationException if the list is read-only
- */
- public function removeAt($index)
- {
- if(!$this->_r)
- {
- if($index>=0 && $index<$this->_c)
- {
- $this->_c--;
- if($index===$this->_c)
- return array_pop($this->_d);
- else
- {
- $item=$this->_d[$index];
- array_splice($this->_d,$index,1);
- return $item;
- }
- }
- else
- throw new TInvalidDataValueException('list_index_invalid',$index);
- }
- else
- throw new TInvalidOperationException('list_readonly',get_class($this));
- }
-
- /**
- * Removes all items in the list.
- * @throws TInvalidOperationException if the list is read-only
- */
- public function clear()
- {
- for($i=$this->_c-1;$i>=0;--$i)
- $this->removeAt($i);
- }
-
- /**
- * @param mixed the item
- * @return boolean whether the list contains the item
- */
- public function contains($item)
- {
- return $this->indexOf($item)>=0;
- }
-
- /**
- * @param mixed the item
- * @return integer the index of the item in the list (0 based), -1 if not found.
- */
- public function indexOf($item)
- {
- if(($index=array_search($item,$this->_d,true))===false)
- return -1;
- else
- return $index;
- }
-
- /**
- * Finds the base item. If found, the item is inserted before it.
- * @param mixed the base item which will be pushed back by the second parameter
- * @param mixed the item
- * @return int the index where the item is inserted
- * @throws TInvalidDataValueException if the base item is not within this list
- * @throws TInvalidOperationException if the list is read-only
- * @since 3.2a
- */
- public function insertBefore($baseitem, $item)
- {
- if(!$this->_r)
- {
- if(($index = $this->indexOf($baseitem)) == -1)
- throw new TInvalidDataValueException('list_item_inexistent');
-
- $this->insertAt($index, $item);
-
- return $index;
- }
- else
- throw new TInvalidOperationException('list_readonly',get_class($this));
- }
-
- /**
- * Finds the base item. If found, the item is inserted after it.
- * @param mixed the base item which comes before the second parameter when added to the list
- * @param mixed the item
- * @return int the index where the item is inserted
- * @throws TInvalidDataValueException if the base item is not within this list
- * @throws TInvalidOperationException if the list is read-only
- * @since 3.2a
- */
- public function insertAfter($baseitem, $item)
- {
- if(!$this->_r)
- {
- if(($index = $this->indexOf($baseitem)) == -1)
- throw new TInvalidDataValueException('list_item_inexistent');
-
- $this->insertAt($index + 1, $item);
-
- return $index + 1;
- }
- else
- throw new TInvalidOperationException('list_readonly',get_class($this));
- }
-
- /**
- * @return array the list of items in array
- */
- public function toArray()
- {
- return $this->_d;
- }
-
- /**
- * Copies iterable data into the list.
- * Note, existing data in the list will be cleared first.
- * @param mixed the data to be copied from, must be an array or object implementing Traversable
- * @throws TInvalidDataTypeException If data is neither an array nor a Traversable.
- */
- public function copyFrom($data)
- {
- if(is_array($data) || ($data instanceof Traversable))
- {
- if($this->_c>0)
- $this->clear();
- foreach($data as $item)
- $this->add($item);
- }
- else if($data!==null)
- throw new TInvalidDataTypeException('list_data_not_iterable');
- }
-
- /**
- * Merges iterable data into the map.
- * New data will be appended to the end of the existing data.
- * @param mixed the data to be merged with, must be an array or object implementing Traversable
- * @throws TInvalidDataTypeException If data is neither an array nor an iterator.
- */
- public function mergeWith($data)
- {
- if(is_array($data) || ($data instanceof Traversable))
- {
- foreach($data as $item)
- $this->add($item);
- }
- else if($data!==null)
- throw new TInvalidDataTypeException('list_data_not_iterable');
- }
-
- /**
- * Returns whether there is an item at the specified offset.
- * This method is required by the interface ArrayAccess.
- * @param integer the offset to check on
- * @return boolean
- */
- public function offsetExists($offset)
- {
- return ($offset>=0 && $offset<$this->_c);
- }
-
- /**
- * Returns the item at the specified offset.
- * This method is required by the interface ArrayAccess.
- * @param integer the offset to retrieve item.
- * @return mixed the item at the offset
- * @throws TInvalidDataValueException if the offset is invalid
- */
- public function offsetGet($offset)
- {
- return $this->itemAt($offset);
- }
-
- /**
- * Sets the item at the specified offset.
- * This method is required by the interface ArrayAccess.
- * @param integer the offset to set item
- * @param mixed the item value
- */
- public function offsetSet($offset,$item)
- {
- if($offset===null || $offset===$this->_c)
- $this->insertAt($this->_c,$item);
- else
- {
- $this->removeAt($offset);
- $this->insertAt($offset,$item);
- }
- }
-
- /**
- * Unsets the item at the specified offset.
- * This method is required by the interface ArrayAccess.
- * @param integer the offset to unset item
- */
- public function offsetUnset($offset)
- {
- $this->removeAt($offset);
- }
-}
-
-
-/**
- * TListIterator class
- *
- * TListIterator implements Iterator interface.
- *
- * TListIterator is used by TList. It allows TList to return a new iterator
- * for traversing the items in the list.
- *
- * @deprecated Issue 264 : ArrayIterator should be used instead
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @version $Id$
- * @package System.Collections
- * @since 3.0
- */
-class TListIterator implements Iterator
-{
- /**
- * @var array the data to be iterated through
- */
- private $_d;
- /**
- * @var integer index of the current item
- */
- private $_i;
- /**
- * @var integer count of the data items
- */
- private $_c;
-
- /**
- * Constructor.
- * @param array the data to be iterated through
- */
- public function __construct(&$data)
- {
- $this->_d=&$data;
- $this->_i=0;
- $this->_c=count($this->_d);
- }
-
- /**
- * Rewinds internal array pointer.
- * This method is required by the interface Iterator.
- */
- public function rewind()
- {
- $this->_i=0;
- }
-
- /**
- * Returns the key of the current array item.
- * This method is required by the interface Iterator.
- * @return integer the key of the current array item
- */
- public function key()
- {
- return $this->_i;
- }
-
- /**
- * Returns the current array item.
- * This method is required by the interface Iterator.
- * @return mixed the current array item
- */
- public function current()
- {
- return $this->_d[$this->_i];
- }
-
- /**
- * Moves the internal pointer to the next array item.
- * This method is required by the interface Iterator.
- */
- public function next()
- {
- $this->_i++;
- }
-
- /**
- * Returns whether there is an item at current position.
- * This method is required by the interface Iterator.
- * @return boolean
- */
- public function valid()
- {
- return $this->_i<$this->_c;
- }
-}
-
+<?php
+/**
+ * TList, TListIterator classes
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2012 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Collections
+ */
+
+/**
+ * TList class
+ *
+ * TList implements an integer-indexed collection class.
+ *
+ * You can access, append, insert, remove an item by using
+ * {@link itemAt}, {@link add}, {@link insertAt}, {@link remove}, and {@link removeAt}.
+ * To get the number of the items in the list, use {@link getCount}.
+ * TList can also be used like a regular array as follows,
+ * <code>
+ * $list[]=$item; // append at the end
+ * $list[$index]=$item; // $index must be between 0 and $list->Count
+ * unset($list[$index]); // remove the item at $index
+ * if(isset($list[$index])) // if the list has an item at $index
+ * foreach($list as $index=>$item) // traverse each item in the list
+ * $n=count($list); // returns the number of items in the list
+ * </code>
+ *
+ * To extend TList by doing additional operations with each addition or removal
+ * operation, override {@link insertAt()}, and {@link removeAt()}.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id$
+ * @package System.Collections
+ * @since 3.0
+ */
+class TList extends TComponent implements IteratorAggregate,ArrayAccess,Countable
+{
+ /**
+ * internal data storage
+ * @var array
+ */
+ private $_d=array();
+ /**
+ * number of items
+ * @var integer
+ */
+ private $_c=0;
+ /**
+ * @var boolean whether this list is read-only
+ */
+ private $_r=false;
+
+ /**
+ * Constructor.
+ * Initializes the list with an array or an iterable object.
+ * @param array|Iterator the initial data. Default is null, meaning no initialization.
+ * @param boolean whether the list is read-only
+ * @throws TInvalidDataTypeException If data is not null and neither an array nor an iterator.
+ */
+ public function __construct($data=null,$readOnly=false)
+ {
+ if($data!==null)
+ $this->copyFrom($data);
+ $this->setReadOnly($readOnly);
+ }
+
+ /**
+ * @return boolean whether this list is read-only or not. Defaults to false.
+ */
+ public function getReadOnly()
+ {
+ return $this->_r;
+ }
+
+ /**
+ * @param boolean whether this list is read-only or not
+ */
+ protected function setReadOnly($value)
+ {
+ $this->_r=TPropertyValue::ensureBoolean($value);
+ }
+
+ /**
+ * Returns an iterator for traversing the items in the list.
+ * This method is required by the interface IteratorAggregate.
+ * @return Iterator an iterator for traversing the items in the list.
+ */
+ public function getIterator()
+ {
+ return new ArrayIterator( $this->_d );
+ }
+
+ /**
+ * Returns the number of items in the list.
+ * This method is required by Countable interface.
+ * @return integer number of items in the list.
+ */
+ public function count()
+ {
+ return $this->getCount();
+ }
+
+ /**
+ * @return integer the number of items in the list
+ */
+ public function getCount()
+ {
+ return $this->_c;
+ }
+
+ /**
+ * Returns the item at the specified offset.
+ * This method is exactly the same as {@link offsetGet}.
+ * @param integer the index of the item
+ * @return mixed the item at the index
+ * @throws TInvalidDataValueException if the index is out of the range
+ */
+ public function itemAt($index)
+ {
+ if($index>=0 && $index<$this->_c)
+ return $this->_d[$index];
+ else
+ throw new TInvalidDataValueException('list_index_invalid',$index);
+ }
+
+ /**
+ * Appends an item at the end of the list.
+ * @param mixed new item
+ * @return integer the zero-based index at which the item is added
+ * @throws TInvalidOperationException if the list is read-only
+ */
+ public function add($item)
+ {
+ $this->insertAt($this->_c,$item);
+ return $this->_c-1;
+ }
+
+ /**
+ * Inserts an item at the specified position.
+ * Original item at the position and the next items
+ * will be moved one step towards the end.
+ * @param integer the specified position.
+ * @param mixed new item
+ * @throws TInvalidDataValueException If the index specified exceeds the bound
+ * @throws TInvalidOperationException if the list is read-only
+ */
+ public function insertAt($index,$item)
+ {
+ if(!$this->_r)
+ {
+ if($index===$this->_c)
+ $this->_d[$this->_c++]=$item;
+ else if($index>=0 && $index<$this->_c)
+ {
+ array_splice($this->_d,$index,0,array($item));
+ $this->_c++;
+ }
+ else
+ throw new TInvalidDataValueException('list_index_invalid',$index);
+ }
+ else
+ throw new TInvalidOperationException('list_readonly',get_class($this));
+ }
+
+ /**
+ * Removes an item from the list.
+ * The list will first search for the item.
+ * The first item found will be removed from the list.
+ * @param mixed the item to be removed.
+ * @return integer the index at which the item is being removed
+ * @throws TInvalidDataValueException If the item does not exist
+ * @throws TInvalidOperationException if the list is read-only
+ */
+ public function remove($item)
+ {
+ if(!$this->_r)
+ {
+ if(($index=$this->indexOf($item))>=0)
+ {
+ $this->removeAt($index);
+ return $index;
+ }
+ else
+ throw new TInvalidDataValueException('list_item_inexistent');
+ }
+ else
+ throw new TInvalidOperationException('list_readonly',get_class($this));
+ }
+
+ /**
+ * Removes an item at the specified position.
+ * @param integer the index of the item to be removed.
+ * @return mixed the removed item.
+ * @throws TInvalidDataValueException If the index specified exceeds the bound
+ * @throws TInvalidOperationException if the list is read-only
+ */
+ public function removeAt($index)
+ {
+ if(!$this->_r)
+ {
+ if($index>=0 && $index<$this->_c)
+ {
+ $this->_c--;
+ if($index===$this->_c)
+ return array_pop($this->_d);
+ else
+ {
+ $item=$this->_d[$index];
+ array_splice($this->_d,$index,1);
+ return $item;
+ }
+ }
+ else
+ throw new TInvalidDataValueException('list_index_invalid',$index);
+ }
+ else
+ throw new TInvalidOperationException('list_readonly',get_class($this));
+ }
+
+ /**
+ * Removes all items in the list.
+ * @throws TInvalidOperationException if the list is read-only
+ */
+ public function clear()
+ {
+ for($i=$this->_c-1;$i>=0;--$i)
+ $this->removeAt($i);
+ }
+
+ /**
+ * @param mixed the item
+ * @return boolean whether the list contains the item
+ */
+ public function contains($item)
+ {
+ return $this->indexOf($item)>=0;
+ }
+
+ /**
+ * @param mixed the item
+ * @return integer the index of the item in the list (0 based), -1 if not found.
+ */
+ public function indexOf($item)
+ {
+ if(($index=array_search($item,$this->_d,true))===false)
+ return -1;
+ else
+ return $index;
+ }
+
+ /**
+ * Finds the base item. If found, the item is inserted before it.
+ * @param mixed the base item which will be pushed back by the second parameter
+ * @param mixed the item
+ * @return int the index where the item is inserted
+ * @throws TInvalidDataValueException if the base item is not within this list
+ * @throws TInvalidOperationException if the list is read-only
+ * @since 3.2a
+ */
+ public function insertBefore($baseitem, $item)
+ {
+ if(!$this->_r)
+ {
+ if(($index = $this->indexOf($baseitem)) == -1)
+ throw new TInvalidDataValueException('list_item_inexistent');
+
+ $this->insertAt($index, $item);
+
+ return $index;
+ }
+ else
+ throw new TInvalidOperationException('list_readonly',get_class($this));
+ }
+
+ /**
+ * Finds the base item. If found, the item is inserted after it.
+ * @param mixed the base item which comes before the second parameter when added to the list
+ * @param mixed the item
+ * @return int the index where the item is inserted
+ * @throws TInvalidDataValueException if the base item is not within this list
+ * @throws TInvalidOperationException if the list is read-only
+ * @since 3.2a
+ */
+ public function insertAfter($baseitem, $item)
+ {
+ if(!$this->_r)
+ {
+ if(($index = $this->indexOf($baseitem)) == -1)
+ throw new TInvalidDataValueException('list_item_inexistent');
+
+ $this->insertAt($index + 1, $item);
+
+ return $index + 1;
+ }
+ else
+ throw new TInvalidOperationException('list_readonly',get_class($this));
+ }
+
+ /**
+ * @return array the list of items in array
+ */
+ public function toArray()
+ {
+ return $this->_d;
+ }
+
+ /**
+ * Copies iterable data into the list.
+ * Note, existing data in the list will be cleared first.
+ * @param mixed the data to be copied from, must be an array or object implementing Traversable
+ * @throws TInvalidDataTypeException If data is neither an array nor a Traversable.
+ */
+ public function copyFrom($data)
+ {
+ if(is_array($data) || ($data instanceof Traversable))
+ {
+ if($this->_c>0)
+ $this->clear();
+ foreach($data as $item)
+ $this->add($item);
+ }
+ else if($data!==null)
+ throw new TInvalidDataTypeException('list_data_not_iterable');
+ }
+
+ /**
+ * Merges iterable data into the map.
+ * New data will be appended to the end of the existing data.
+ * @param mixed the data to be merged with, must be an array or object implementing Traversable
+ * @throws TInvalidDataTypeException If data is neither an array nor an iterator.
+ */
+ public function mergeWith($data)
+ {
+ if(is_array($data) || ($data instanceof Traversable))
+ {
+ foreach($data as $item)
+ $this->add($item);
+ }
+ else if($data!==null)
+ throw new TInvalidDataTypeException('list_data_not_iterable');
+ }
+
+ /**
+ * Returns whether there is an item at the specified offset.
+ * This method is required by the interface ArrayAccess.
+ * @param integer the offset to check on
+ * @return boolean
+ */
+ public function offsetExists($offset)
+ {
+ return ($offset>=0 && $offset<$this->_c);
+ }
+
+ /**
+ * Returns the item at the specified offset.
+ * This method is required by the interface ArrayAccess.
+ * @param integer the offset to retrieve item.
+ * @return mixed the item at the offset
+ * @throws TInvalidDataValueException if the offset is invalid
+ */
+ public function offsetGet($offset)
+ {
+ return $this->itemAt($offset);
+ }
+
+ /**
+ * Sets the item at the specified offset.
+ * This method is required by the interface ArrayAccess.
+ * @param integer the offset to set item
+ * @param mixed the item value
+ */
+ public function offsetSet($offset,$item)
+ {
+ if($offset===null || $offset===$this->_c)
+ $this->insertAt($this->_c,$item);
+ else
+ {
+ $this->removeAt($offset);
+ $this->insertAt($offset,$item);
+ }
+ }
+
+ /**
+ * Unsets the item at the specified offset.
+ * This method is required by the interface ArrayAccess.
+ * @param integer the offset to unset item
+ */
+ public function offsetUnset($offset)
+ {
+ $this->removeAt($offset);
+ }
+}
+
+
+/**
+ * TListIterator class
+ *
+ * TListIterator implements Iterator interface.
+ *
+ * TListIterator is used by TList. It allows TList to return a new iterator
+ * for traversing the items in the list.
+ *
+ * @deprecated Issue 264 : ArrayIterator should be used instead
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id$
+ * @package System.Collections
+ * @since 3.0
+ */
+class TListIterator implements Iterator
+{
+ /**
+ * @var array the data to be iterated through
+ */
+ private $_d;
+ /**
+ * @var integer index of the current item
+ */
+ private $_i;
+ /**
+ * @var integer count of the data items
+ */
+ private $_c;
+
+ /**
+ * Constructor.
+ * @param array the data to be iterated through
+ */
+ public function __construct(&$data)
+ {
+ $this->_d=&$data;
+ $this->_i=0;
+ $this->_c=count($this->_d);
+ }
+
+ /**
+ * Rewinds internal array pointer.
+ * This method is required by the interface Iterator.
+ */
+ public function rewind()
+ {
+ $this->_i=0;
+ }
+
+ /**
+ * Returns the key of the current array item.
+ * This method is required by the interface Iterator.
+ * @return integer the key of the current array item
+ */
+ public function key()
+ {
+ return $this->_i;
+ }
+
+ /**
+ * Returns the current array item.
+ * This method is required by the interface Iterator.
+ * @return mixed the current array item
+ */
+ public function current()
+ {
+ return $this->_d[$this->_i];
+ }
+
+ /**
+ * Moves the internal pointer to the next array item.
+ * This method is required by the interface Iterator.
+ */
+ public function next()
+ {
+ $this->_i++;
+ }
+
+ /**
+ * Returns whether there is an item at current position.
+ * This method is required by the interface Iterator.
+ * @return boolean
+ */
+ public function valid()
+ {
+ return $this->_i<$this->_c;
+ }
+}
+