CDataProviderIterator
| 包 | system.web |
|---|---|
| 继承 | class CDataProviderIterator » CComponent |
| 实现 | Iterator, Traversable, Countable |
| 可用自 | 1.1.13 |
| 源码 | framework/web/CDataProviderIterator.php |
CDataProviderIterator allows iteration over large data sets without holding the entire set in memory.
CDataProviderIterator iterates over the results of a data provider, starting at the first page of results and ending at the last page. It is usually only suited for use with CActiveDataProvider.
For example, the following code will iterate over all registered users (active record class User) without running out of memory, even if there are millions of users in the database.
CDataProviderIterator iterates over the results of a data provider, starting at the first page of results and ending at the last page. It is usually only suited for use with CActiveDataProvider.
For example, the following code will iterate over all registered users (active record class User) without running out of memory, even if there are millions of users in the database.
$dataProvider = new CActiveDataProvider("User");
$iterator = new CDataProviderIterator($dataProvider);
foreach($iterator as $user) {
echo $user->name."\n";
}
公共属性
| 属性 | 类型 | 描述 | 被定义在 |
|---|---|---|---|
| dataProvider | CDataProvider | Returns the data provider to iterate over | CDataProviderIterator |
| totalItemCount | integer | Gets the total number of items to iterate over | CDataProviderIterator |
公共方法
| 方法 | 描述 | 被定义在 |
|---|---|---|
| __call() | Calls the named method which is not a class method. | CComponent |
| __construct() | Constructor. | CDataProviderIterator |
| __get() | Returns a property value, an event handler list or a behavior based on its name. | CComponent |
| __isset() | Checks if a property value is null. | CComponent |
| __set() | Sets value of a component property. | CComponent |
| __unset() | Sets a component property to be null. | CComponent |
| asa() | Returns the named behavior object. | CComponent |
| attachBehavior() | Attaches a behavior to this component. | CComponent |
| attachBehaviors() | Attaches a list of behaviors to the component. | CComponent |
| attachEventHandler() | Attaches an event handler to an event. | CComponent |
| canGetProperty() | Determines whether a property can be read. | CComponent |
| canSetProperty() | Determines whether a property can be set. | CComponent |
| count() | Gets the total number of items in the dataProvider. | CDataProviderIterator |
| current() | Gets the current item in the list. | CDataProviderIterator |
| detachBehavior() | Detaches a behavior from the component. | CComponent |
| detachBehaviors() | Detaches all behaviors from the component. | CComponent |
| detachEventHandler() | Detaches an existing event handler. | CComponent |
| disableBehavior() | Disables an attached behavior. | CComponent |
| disableBehaviors() | Disables all behaviors attached to this component. | CComponent |
| enableBehavior() | Enables an attached behavior. | CComponent |
| enableBehaviors() | Enables all behaviors attached to this component. | CComponent |
| evaluateExpression() | Evaluates a PHP expression or callback under the context of this component. | CComponent |
| getDataProvider() | Returns the data provider to iterate over | CDataProviderIterator |
| getEventHandlers() | Returns the list of attached event handlers for an event. | CComponent |
| getTotalItemCount() | Gets the total number of items to iterate over | CDataProviderIterator |
| hasEvent() | Determines whether an event is defined. | CComponent |
| hasEventHandler() | Checks whether the named event has attached handlers. | CComponent |
| hasProperty() | Determines whether a property is defined. | CComponent |
| key() | Gets the key of the current item. | CDataProviderIterator |
| next() | Moves the pointer to the next item in the list. | CDataProviderIterator |
| raiseEvent() | Raises an event. | CComponent |
| rewind() | Rewinds the iterator to the start of the list. | CDataProviderIterator |
| valid() | Checks if the current position is valid or not. | CDataProviderIterator |
属性详情
dataProvider
属性
只读
public CDataProvider getDataProvider()
Returns the data provider to iterate over
totalItemCount
属性
只读
public integer getTotalItemCount()
Gets the total number of items to iterate over
方法详情
__construct()
方法
|
public void __construct(CDataProvider $dataProvider, integer $pageSize=NULL)
| ||
| $dataProvider | CDataProvider | the data provider to iterate over |
| $pageSize | integer | pageSize to use for iteration. This is the number of objects loaded into memory at the same time. |
源码： framework/web/CDataProviderIterator.php#48 (显示)
public function __construct(CDataProvider $dataProvider, $pageSize=null)
{
$this->_dataProvider=$dataProvider;
$this->_totalItemCount=$dataProvider->getTotalItemCount();
if(($pagination=$this->_dataProvider->getPagination())===false)
$this->_dataProvider->setPagination($pagination=new CPagination());
if($pageSize!==null)
$pagination->setPageSize($pageSize);
}
Constructor.
count()
方法
|
public integer count()
| ||
| {return} | integer | the total number of items |
源码： framework/web/CDataProviderIterator.php#151 (显示)
public function count()
{
return $this->_totalItemCount;
}
Gets the total number of items in the dataProvider. This method is required by the Countable interface.
current()
方法
|
public mixed current()
| ||
| {return} | mixed | the current item in the list |
源码： framework/web/CDataProviderIterator.php#93 (显示)
public function current()
{
return $this->_items[$this->_currentIndex];
}
Gets the current item in the list. This method is required by the Iterator interface.
getDataProvider()
方法
|
public CDataProvider getDataProvider()
| ||
| {return} | CDataProvider | the data provider to iterate over |
源码： framework/web/CDataProviderIterator.php#64 (显示)
public function getDataProvider()
{
return $this->_dataProvider;
}
Returns the data provider to iterate over
getTotalItemCount()
方法
|
public integer getTotalItemCount()
| ||
| {return} | integer | the total number of items to iterate over |
源码： framework/web/CDataProviderIterator.php#73 (显示)
public function getTotalItemCount()
{
return $this->_totalItemCount;
}
Gets the total number of items to iterate over
key()
方法
|
public integer key()
| ||
| {return} | integer | the key of the current item |
源码： framework/web/CDataProviderIterator.php#103 (显示)
public function key()
{
$pageSize=$this->_dataProvider->getPagination()->getPageSize();
return $this->_currentPage*$pageSize+$this->_currentIndex;
}
Gets the key of the current item. This method is required by the Iterator interface.
loadPage()
方法
|
protected array loadPage()
| ||
| {return} | array | the items from the next page of results |
源码： framework/web/CDataProviderIterator.php#82 (显示)
protected function loadPage()
{
$this->_dataProvider->getPagination()->setCurrentPage($this->_currentPage);
return $this->_items=$this->dataProvider->getData(true);
}
Loads a page of items
next()
方法
|
public void next()
|
源码： framework/web/CDataProviderIterator.php#113 (显示)
public function next()
{
$pageSize=$this->_dataProvider->getPagination()->getPageSize();
$this->_currentIndex++;
if($this->_currentIndex >= $pageSize)
{
$this->_currentPage++;
$this->_currentIndex=0;
$this->loadPage();
}
}
Moves the pointer to the next item in the list. This method is required by the Iterator interface.
rewind()
方法
|
public void rewind()
|
源码： framework/web/CDataProviderIterator.php#129 (显示)
public function rewind()
{
$this->_currentIndex=0;
$this->_currentPage=0;
$this->loadPage();
}
Rewinds the iterator to the start of the list. This method is required by the Iterator interface.
valid()
方法
|
public boolean valid()
| ||
| {return} | boolean | true if this index is valid |
源码： framework/web/CDataProviderIterator.php#141 (显示)
public function valid()
{
return $this->key() < $this->_totalItemCount;
}
Checks if the current position is valid or not. This method is required by the Iterator interface.