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<?php
/**
* This file contains the foundation classes for component-based and event-driven programming.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.yiiframework.com/
* @copyright Copyright &copy; 2008-2010 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CComponent is the base class for all components.
*
* CComponent implements the protocol of defining, using properties and events.
*
* A property is defined by a getter method, and/or a setter method.
* Properties can be accessed in the way like accessing normal object members.
* Reading or writing a property will cause the invocation of the corresponding
* getter or setter method, e.g
* <pre>
* $a=$component->text; // equivalent to $a=$component->getText();
* $component->text='abc'; // equivalent to $component->setText('abc');
* </pre>
* The signatures of getter and setter methods are as follows,
* <pre>
* // getter, defines a readable property 'text'
* public function getText() { ... }
* // setter, defines a writable property 'text' with $value to be set to the property
* public function setText($value) { ... }
* </pre>
*
* An event is defined by the presence of a method whose name starts with 'on'.
* The event name is the method name. When an event is raised, functions
* (called event handlers) attached to the event will be invoked automatically.
*
* An event can be raised by calling {@link raiseEvent} method, upon which
* the attached event handlers will be invoked automatically in the order they
* are attached to the event. Event handlers must have the following signature,
* <pre>
* function eventHandler($event) { ... }
* </pre>
* where $event includes parameters associated with the event.
*
* To attach an event handler to an event, see {@link attachEventHandler}.
* You can also use the following syntax:
* <pre>
* $component->onClick=$callback; // or $component->onClick->add($callback);
* </pre>
* where $callback refers to a valid PHP callback. Below we show some callback examples:
* <pre>
* 'handleOnClick' // handleOnClick() is a global function
* array($object,'handleOnClick') // using $object->handleOnClick()
* array('Page','handleOnClick') // using Page::handleOnClick()
* </pre>
*
* To raise an event, use {@link raiseEvent}. The on-method defining an event is
* commonly written like the following:
* <pre>
* public function onClick($event)
* {
* $this->raiseEvent('onClick',$event);
* }
* </pre>
* where <code>$event</code> is an instance of {@link CEvent} or its child class.
* One can then raise the event by calling the on-method instead of {@link raiseEvent} directly.
*
* Both property names and event names are case-insensitive.
*
* Starting from version 1.0.2, CComponent supports behaviors. A behavior is an
* instance of {@link IBehavior} which is attached to a component. The methods of
* the behavior can be invoked as if they belong to the component. Multiple behaviors
* can be attached to the same component.
*
* To attach a behavior to a component, call {@link attachBehavior}; and to detach the behavior
* from the component, call {@link detachBehavior}.
*
* A behavior can be temporarily enabled or disabled by calling {@link enableBehavior}
* or {@link disableBehavior}, respectively. When disabled, the behavior methods cannot
* be invoked via the component.
*
* Starting from version 1.1.0, a behavior's properties (either its public member variables or
* its properties defined via getters and/or setters) can be accessed through the component it
* is attached to.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @version $Id$
* @package system.base
* @since 1.0
*/
class CComponent
{
private $_e;
private $_m;
/**
* Returns a property value, an event handler list or a behavior based on its name.
* Do not call this method. This is a PHP magic method that we override
* to allow using the following syntax to read a property or obtain event handlers:
* <pre>
* $value=$component->propertyName;
* $handlers=$component->eventName;
* </pre>
* @param string the property name or event name
* @return mixed the property value, event handlers attached to the event, or the named behavior (since version 1.0.2)
* @throws CException if the property or event is not defined
* @see __set
*/
public function __get($name)
{
$getter='get'.$name;
if(method_exists($this,$getter))
return $this->$getter();
else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
{
// duplicating getEventHandlers() here for performance
$name=strtolower($name);
if(!isset($this->_e[$name]))
$this->_e[$name]=new CList;
return $this->_e[$name];
}
else if(isset($this->_m[$name]))
return $this->_m[$name];
else if(is_array($this->_m))
{
foreach($this->_m as $object)
{
if($object->getEnabled() && (property_exists($object,$name) || $object->canGetProperty($name)))
return $object->$name;
}
}
throw new CException(Yii::t('yii','Property "{class}.{property}" is not defined.',
array('{class}'=>get_class($this), '{property}'=>$name)));
}
/**
* Sets value of a component property.
* Do not call this method. This is a PHP magic method that we override
* to allow using the following syntax to set a property or attach an event handler
* <pre>
* $this->propertyName=$value;
* $this->eventName=$callback;
* </pre>
* @param string the property name or the event name
* @param mixed the property value or callback
* @throws CException if the property/event is not defined or the property is read only.
* @see __get
*/
public function __set($name,$value)
{
$setter='set'.$name;
if(method_exists($this,$setter))
return $this->$setter($value);
else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
{
// duplicating getEventHandlers() here for performance
$name=strtolower($name);
if(!isset($this->_e[$name]))
$this->_e[$name]=new CList;
return $this->_e[$name]->add($value);
}
else if(is_array($this->_m))
{
foreach($this->_m as $object)
{
if($object->getEnabled() && (property_exists($object,$name) || $object->canSetProperty($name)))
return $object->$name=$value;
}
}
if(method_exists($this,'get'.$name))
throw new CException(Yii::t('yii','Property "{class}.{property}" is read only.',
array('{class}'=>get_class($this), '{property}'=>$name)));
else
throw new CException(Yii::t('yii','Property "{class}.{property}" is not defined.',
array('{class}'=>get_class($this), '{property}'=>$name)));
}
/**
* Checks if a property value is null.
* Do not call this method. This is a PHP magic method that we override
* to allow using isset() to detect if a component property is set or not.
* @param string the property name or the event name
* @since 1.0.1
*/
public function __isset($name)
{
$getter='get'.$name;
if(method_exists($this,$getter))
return $this->$getter()!==null;
else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
{
$name=strtolower($name);
return isset($this->_e[$name]) && $this->_e[$name]->getCount();
}
else
return false;
}
/**
* Sets a component property to be null.
* Do not call this method. This is a PHP magic method that we override
* to allow using unset() to set a component property to be null.
* @param string the property name or the event name
* @throws CException if the property is read only.
* @since 1.0.1
*/
public function __unset($name)
{
$setter='set'.$name;
if(method_exists($this,$setter))
$this->$setter(null);
else if(strncasecmp($name,'on',2)===0 && method_exists($this,$name))
unset($this->_e[strtolower($name)]);
else if(method_exists($this,'get'.$name))
throw new CException(Yii::t('yii','Property "{class}.{property}" is read only.',
array('{class}'=>get_class($this), '{property}'=>$name)));
}
/**
* Calls the named method which is not a class method.
* Do not call this method. This is a PHP magic method that we override
* to implement the behavior feature.
* @param string the method name
* @param array method parameters
* @return mixed the method return value
* @since 1.0.2
*/
public function __call($name,$parameters)
{
if($this->_m!==null)
{
foreach($this->_m as $object)
{
if($object->getEnabled() && method_exists($object,$name))
return call_user_func_array(array($object,$name),$parameters);
}
}
throw new CException(Yii::t('yii','{class} does not have a method named "{name}".',
array('{class}'=>get_class($this), '{name}'=>$name)));
}
/**
* Returns the named behavior object.
* The name 'asa' stands for 'as a'.
* @param string the behavior name
* @return IBehavior the behavior object, or null if the behavior does not exist
* @since 1.0.2
*/
public function asa($behavior)
{
return isset($this->_m[$behavior]) ? $this->_m[$behavior] : null;
}
/**
* Attaches a list of behaviors to the component.
* Each behavior is indexed by its name and should be an instance of
* {@link IBehavior}, a string specifying the behavior class, or an
* array of the following structure:
* <pre>
* array(
* 'class'=>'path.to.BehaviorClass',
* 'property1'=>'value1',
* 'property2'=>'value2',
* )
* </pre>
* @param array list of behaviors to be attached to the component
* @since 1.0.2
*/
public function attachBehaviors($behaviors)
{
foreach($behaviors as $name=>$behavior)
$this->attachBehavior($name,$behavior);
}
/**
* Detaches all behaviors from the component.
* @since 1.0.2
*/
public function detachBehaviors()
{
if($this->_m!==null)
{
foreach($this->_m as $name=>$behavior)
$this->detachBehavior($name);
$this->_m=null;
}
}
/**
* Attaches a behavior to this component.
* This method will create the behavior object based on the given
* configuration. After that, the behavior object will be initialized
* by calling its {@link IBehavior::attach} method.
* @param string the behavior's name. It should uniquely identify this behavior.
* @param mixed the behavior configuration. This is passed as the first
* parameter to {@link YiiBase::createComponent} to create the behavior object.
* @return IBehavior the behavior object
* @since 1.0.2
*/
public function attachBehavior($name,$behavior)
{
if(!($behavior instanceof IBehavior))
$behavior=Yii::createComponent($behavior);
$behavior->setEnabled(true);
$behavior->attach($this);
return $this->_m[$name]=$behavior;
}
/**
* Detaches a behavior from the component.
* The behavior's {@link IBehavior::detach} method will be invoked.
* @param string the behavior's name. It uniquely identifies the behavior.
* @return IBehavior the detached behavior. Null if the behavior does not exist.
* @since 1.0.2
*/
public function detachBehavior($name)
{
if(isset($this->_m[$name]))
{
$this->_m[$name]->detach($this);
$behavior=$this->_m[$name];
unset($this->_m[$name]);
return $behavior;
}
}
/**
* Enables all behaviors attached to this component.
* @since 1.0.2
*/
public function enableBehaviors()
{
if($this->_m!==null)
{
foreach($this->_m as $behavior)
$behavior->setEnabled(true);
}
}
/**
* Disables all behaviors attached to this component.
* @since 1.0.2
*/
public function disableBehaviors()
{
if($this->_m!==null)
{
foreach($this->_m as $behavior)
$behavior->setEnabled(false);
}
}
/**
* Enables an attached behavior.
* A behavior is only effective when it is enabled.
* A behavior is enabled when first attached.
* @param string the behavior's name. It uniquely identifies the behavior.
* @since 1.0.2
*/
public function enableBehavior($name)
{
if(isset($this->_m[$name]))
$this->_m[$name]->setEnabled(true);
}
/**
* Disables an attached behavior.
* A behavior is only effective when it is enabled.
* @param string the behavior's name. It uniquely identifies the behavior.
* @since 1.0.2
*/
public function disableBehavior($name)
{
if(isset($this->_m[$name]))
$this->_m[$name]->setEnabled(false);
}
/**
* Determines whether a property is defined.
* A property is defined if there is a getter or setter method
* defined in the class. Note, property names are case-insensitive.
* @param string the property name
* @return boolean whether the property is defined
* @see canGetProperty
* @see canSetProperty
*/
public function hasProperty($name)
{
return method_exists($this,'get'.$name) || method_exists($this,'set'.$name);
}
/**
* Determines whether a property can be read.
* A property can be read if the class has a getter method
* for the property name. Note, property name is case-insensitive.
* @param string the property name
* @return boolean whether the property can be read
* @see canSetProperty
*/
public function canGetProperty($name)
{
return method_exists($this,'get'.$name);
}
/**
* Determines whether a property can be set.
* A property can be written if the class has a setter method
* for the property name. Note, property name is case-insensitive.
* @param string the property name
* @return boolean whether the property can be written
* @see canGetProperty
*/
public function canSetProperty($name)
{
return method_exists($this,'set'.$name);
}
/**
* Determines whether an event is defined.
* An event is defined if the class has a method named like 'onXXX'.
* Note, event name is case-insensitive.
* @param string the event name
* @return boolean whether an event is defined
*/
public function hasEvent($name)
{
return !strncasecmp($name,'on',2) && method_exists($this,$name);
}
/**
* Checks whether the named event has attached handlers.
* @param string the event name
* @return boolean whether an event has been attached one or several handlers
*/
public function hasEventHandler($name)
{
$name=strtolower($name);
return isset($this->_e[$name]) && $this->_e[$name]->getCount()>0;
}
/**
* Returns the list of attached event handlers for an event.
* @param string the event name
* @return CList list of attached event handlers for the event
* @throws CException if the event is not defined
*/
public function getEventHandlers($name)
{
if($this->hasEvent($name))
{
$name=strtolower($name);
if(!isset($this->_e[$name]))
$this->_e[$name]=new CList;
return $this->_e[$name];
}
else
throw new CException(Yii::t('yii','Event "{class}.{event}" is not defined.',
array('{class}'=>get_class($this), '{event}'=>$name)));
}
/**
* Attaches an event handler to an event.
*
* An event handler must be a valid PHP callback, i.e., a string referring to
* a global function name, or an array containing two elements with
* the first element being an object and the second element a method name
* of the object.
*
* An event handler must be defined with the following signature,
* <pre>
* function handlerName($event) {}
* </pre>
* where $event includes parameters associated with the event.
*
* This is a convenient method of attaching a handler to an event.
* It is equivalent to the following code:
* <pre>
* $component->getEventHandlers($eventName)->add($eventHandler);
* </pre>
*
* Using {@link getEventHandlers}, one can also specify the excution order
* of multiple handlers attaching to the same event. For example:
* <pre>
* $component->getEventHandlers($eventName)->insertAt(0,$eventHandler);
* </pre>
* makes the handler to be invoked first.
*
* @param string the event name
* @param callback the event handler
* @throws CException if the event is not defined
* @see detachEventHandler
*/
public function attachEventHandler($name,$handler)
{
$this->getEventHandlers($name)->add($handler);
}
/**
* Detaches an existing event handler.
* This method is the opposite of {@link attachEventHandler}.
* @param string event name
* @param callback the event handler to be removed
* @return boolean if the detachment process is successful
* @see attachEventHandler
*/
public function detachEventHandler($name,$handler)
{
if($this->hasEventHandler($name))
return $this->getEventHandlers($name)->remove($handler)!==false;
else
return false;
}
/**
* Raises an event.
* This method represents the happening of an event. It invokes
* all attached handlers for the event.
* @param string the event name
* @param CEvent the event parameter
* @throws CException if the event is undefined or an event handler is invalid.
*/
public function raiseEvent($name,$event)
{
$name=strtolower($name);
if(isset($this->_e[$name]))
{
foreach($this->_e[$name] as $handler)
{
if(is_string($handler))
call_user_func($handler,$event);
else if(is_callable($handler,true))
{
if(is_array($handler))
{
// an array: 0 - object, 1 - method name
list($object,$method)=$handler;
if(is_string($object)) // static method call
call_user_func($handler,$event);
else if(method_exists($object,$method))
$object->$method($event);
else
throw new CException(Yii::t('yii','Event "{class}.{event}" is attached with an invalid handler "{handler}".',
array('{class}'=>get_class($this), '{event}'=>$name, '{handler}'=>$handler[1])));
}
else // PHP 5.3: anonymous function
call_user_func($handler,$event);
}
else
throw new CException(Yii::t('yii','Event "{class}.{event}" is attached with an invalid handler "{handler}".',
array('{class}'=>get_class($this), '{event}'=>$name, '{handler}'=>gettype($handler))));
// stop further handling if param.handled is set true
if(($event instanceof CEvent) && $event->handled)
return;
}
}
else if(YII_DEBUG && !$this->hasEvent($name))
throw new CException(Yii::t('yii','Event "{class}.{event}" is not defined.',
array('{class}'=>get_class($this), '{event}'=>$name)));
}
/**
* Evaluates a PHP expression or callback under the context of this component.
*
* Valid PHP callback can be class method name in the form of
* array(ClassName/Object, MethodName), or anonymous function (only available in PHP 5.3.0 or above).
*
* If a PHP callback is used, the corresponding function/method signature should be
* <pre>
* function foo($param1, $param2, ..., $component) { ... }
* </pre>
* where the array elements in the second parameter to this method will be passed
* to the callback as $param1, $param2, ...; and the last parameter will be the component itself.
*
* If a PHP expression is used, the second parameter will be "extracted" into PHP variables
* that can be directly accessed in the expression. See {@link http://us.php.net/manual/en/function.extract.php PHP extract}
* for more details. In the expression, the component object can be accessed using $this.
*
* @var mixed a PHP expression or PHP callback to be evaluated.
* @param array additional parameters to be passed to the above expression/callback.
* @return mixed the expression result
* @since 1.1.0
*/
public function evaluateExpression($_expression_,$_data_=array())
{
if(is_string($_expression_))
{
extract($_data_);
return eval('return '.$_expression_.';');
}
else
{
$_data_[]=$this;
return call_user_func_array($_expression_, $_data_);
}
}
}
/**
* CEvent is the base class for all event classes.
*
* It encapsulates the parameters associated with an event.
* The {@link sender} property describes who raises the event.
* And the {@link handled} property indicates if the event is handled.
* If an event handler sets {@link handled} to true, those handlers
* that are not invoked yet will not be invoked anymore.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @version $Id$
* @package system.base
* @since 1.0
*/
class CEvent extends CComponent
{
/**
* @var object the sender of this event
*/
public $sender;
/**
* @var boolean whether the event is handled. Defaults to false.
* When a handler sets this true, the rest uninvoked handlers will not be invoked anymore.
*/
public $handled=false;
/**
* Constructor.
* @param mixed sender of the event
*/
public function __construct($sender=null)
{
$this->sender=$sender;
}
}
/**
* CEnumerable is the base class for all enumerable types.
*
* To define an enumerable type, extend CEnumberable and define string constants.
* Each constant represents an enumerable value.
* The constant name must be the same as the constant value.
* For example,
* <pre>
* class TextAlign extends CEnumerable
* {
* const Left='Left';
* const Right='Right';
* }
* </pre>
* Then, one can use the enumerable values such as TextAlign::Left and
* TextAlign::Right.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @version $Id$
* @package system.base
* @since 1.0
*/
class CEnumerable
{
}
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