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<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\base;
use Yii;
/**
* @include @yii/base/Component.md
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class Component extends Object
{
/**
* @var array the attached event handlers (event name => handlers)
*/
private $_events;
/**
* @var Behavior[] the attached behaviors (behavior name => behavior)
*/
private $_behaviors;
/**
* Returns the value of a component property.
* This method will check in the following order and act accordingly:
*
* - a property defined by a getter: return the getter result
* - a property of a behavior: return the behavior property value
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `$value = $component->property;`.
* @param string $name the property name
* @return mixed the property value, event handlers attached to the event,
* the behavior, or the value of a behavior's property
* @throws UnknownPropertyException if the property is not defined
* @see __set
*/
public function __get($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
// read property, e.g. getName()
return $this->$getter();
} else {
// behavior property
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canGetProperty($name)) {
return $behavior->$name;
}
}
}
throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
}
/**
* Sets the value of a component property.
* This method will check in the following order and act accordingly:
*
* - a property defined by a setter: set the property value
* - an event in the format of "on xyz": attach the handler to the event "xyz"
* - a behavior in the format of "as xyz": attach the behavior named as "xyz"
* - a property of a behavior: set the behavior property value
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `$component->property = $value;`.
* @param string $name the property name or the event name
* @param mixed $value the property value
* @throws UnknownPropertyException if the property is not defined
* @throws InvalidCallException if the property is read-only.
* @see __get
*/
public function __set($name, $value)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
// set property
$this->$setter($value);
return;
} elseif (strncmp($name, 'on ', 3) === 0) {
// on event: attach event handler
$this->on(trim(substr($name, 3)), $value);
return;
} elseif (strncmp($name, 'as ', 3) === 0) {
// as behavior: attach behavior
$name = trim(substr($name, 3));
$this->attachBehavior($name, $value instanceof Behavior ? $value : Yii::createObject($value));
return;
} else {
// behavior property
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canSetProperty($name)) {
$behavior->$name = $value;
return;
}
}
}
if (method_exists($this, 'get' . $name)) {
throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
} else {
throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
}
}
/**
* Checks if a property value is null.
* This method will check in the following order and act accordingly:
*
* - a property defined by a setter: return whether the property value is null
* - a property of a behavior: return whether the property value is null
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `isset($component->property)`.
* @param string $name the property name or the event name
* @return boolean whether the named property is null
*/
public function __isset($name)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
return $this->$getter() !== null;
} else {
// behavior property
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canGetProperty($name)) {
return $behavior->$name !== null;
}
}
}
return false;
}
/**
* Sets a component property to be null.
* This method will check in the following order and act accordingly:
*
* - a property defined by a setter: set the property value to be null
* - a property of a behavior: set the property value to be null
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when executing `unset($component->property)`.
* @param string $name the property name
* @throws InvalidCallException if the property is read only.
*/
public function __unset($name)
{
$setter = 'set' . $name;
if (method_exists($this, $setter)) {
$this->$setter(null);
return;
} else {
// behavior property
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canSetProperty($name)) {
$behavior->$name = null;
return;
}
}
}
if (method_exists($this, 'get' . $name)) {
throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '.' . $name);
}
}
/**
* Calls the named method which is not a class method.
* If the name refers to a component property whose value is
* an anonymous function, the method will execute the function.
* Otherwise, it will check if any attached behavior has
* the named method and will execute it if available.
*
* Do not call this method directly as it is a PHP magic method that
* will be implicitly called when an unknown method is being invoked.
* @param string $name the method name
* @param array $params method parameters
* @return mixed the method return value
* @throws UnknownMethodException when calling unknown method
*/
public function __call($name, $params)
{
$getter = 'get' . $name;
if (method_exists($this, $getter)) {
$func = $this->$getter();
if ($func instanceof \Closure) {
return call_user_func_array($func, $params);
}
}
$this->ensureBehaviors();
foreach ($this->_behaviors as $object) {
if (method_exists($object, $name)) {
return call_user_func_array(array($object, $name), $params);
}
}
throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
}
/**
* This method is called after the object is created by cloning an existing one.
* It removes all behaviors because they are attached to the old object.
*/
public function __clone()
{
$this->_events = null;
$this->_behaviors = null;
}
/**
* Returns a value indicating whether a property is defined for this component.
* A property is defined if:
*
* - the class has a getter or setter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVar` is true);
* - an attached behavior has a property of the given name (when `$checkBehavior` is true).
*
* @param string $name the property name
* @param boolean $checkVar whether to treat member variables as properties
* @param boolean $checkBehavior whether to treat behaviors' properties as properties of this component
* @return boolean whether the property is defined
* @see canGetProperty
* @see canSetProperty
*/
public function hasProperty($name, $checkVar = true, $checkBehavior = true)
{
return $this->canGetProperty($name, $checkVar, $checkBehavior) || $this->canSetProperty($name, $checkVar, $checkBehavior);
}
/**
* Returns a value indicating whether a property can be read.
* A property can be read if:
*
* - the class has a getter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVar` is true);
* - an attached behavior has a readable property of the given name (when `$checkBehavior` is true).
*
* @param string $name the property name
* @param boolean $checkVar whether to treat member variables as properties
* @param boolean $checkBehavior whether to treat behaviors' properties as properties of this component
* @return boolean whether the property can be read
* @see canSetProperty
*/
public function canGetProperty($name, $checkVar = true, $checkBehavior = true)
{
if (method_exists($this, 'get' . $name) || $checkVar && property_exists($this, $name)) {
return true;
} else {
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canGetProperty($name, $checkVar)) {
return true;
}
}
return false;
}
}
/**
* Returns a value indicating whether a property can be set.
* A property can be written if:
*
* - the class has a setter method associated with the specified name
* (in this case, property name is case-insensitive);
* - the class has a member variable with the specified name (when `$checkVar` is true);
* - an attached behavior has a writable property of the given name (when `$checkBehavior` is true).
*
* @param string $name the property name
* @param boolean $checkVar whether to treat member variables as properties
* @param boolean $checkBehavior whether to treat behaviors' properties as properties of this component
* @return boolean whether the property can be written
* @see canGetProperty
*/
public function canSetProperty($name, $checkVar = true, $checkBehavior = true)
{
if (method_exists($this, 'set' . $name) || $checkVar && property_exists($this, $name)) {
return true;
} else {
$this->ensureBehaviors();
foreach ($this->_behaviors as $behavior) {
if ($behavior->canSetProperty($name, $checkVar)) {
return true;
}
}
return false;
}
}
/**
* Returns a list of behaviors that this component should behave as.
*
* Child classes may override this method to specify the behaviors they want to behave as.
*
* The return value of this method should be an array of behavior objects or configurations
* indexed by behavior names. A behavior configuration can be either a string specifying
* the behavior class or an array of the following structure:
*
* ~~~
* 'behaviorName' => array(
* 'class' => 'BehaviorClass',
* 'property1' => 'value1',
* 'property2' => 'value2',
* )
* ~~~
*
* Note that a behavior class must extend from [[Behavior]]. Behavior names can be strings
* or integers. If the former, they uniquely identify the behaviors. If the latter, the corresponding
* behaviors are anonymous and their properties and methods will NOT be made available via the component
* (however, the behaviors can still respond to the component's events).
*
* Behaviors declared in this method will be attached to the component automatically (on demand).
*
* @return array the behavior configurations.
*/
public function behaviors()
{
return array();
}
/**
* Returns a value indicating whether there is any handler attached to the named event.
* @param string $name the event name
* @return boolean whether there is any handler attached to the event.
*/
public function hasEventHandlers($name)
{
$this->ensureBehaviors();
return !empty($this->_events[$name]);
}
/**
* Attaches an event handler to an event.
*
* An event handler must be a valid PHP callback. The followings are
* some examples:
*
* ~~~
* function ($event) { ... } // anonymous function
* array($object, 'handleClick') // $object->handleClick()
* array('Page', 'handleClick') // Page::handleClick()
* 'handleClick' // global function handleClick()
* ~~~
*
* An event handler must be defined with the following signature,
*
* ~~~
* function ($event)
* ~~~
*
* where `$event` is an [[Event]] object which includes parameters associated with the event.
*
* @param string $name the event name
* @param callback $handler the event handler
* @param mixed $data the data to be passed to the event handler when the event is triggered.
* When the event handler is invoked, this data can be accessed via [[Event::data]].
* @see off()
*/
public function on($name, $handler, $data = null)
{
$this->ensureBehaviors();
$this->_events[$name][] = array($handler, $data);
}
/**
* Detaches an existing event handler from this component.
* This method is the opposite of [[on()]].
* @param string $name event name
* @param callback $handler the event handler to be removed.
* If it is null, all handlers attached to the named event will be removed.
* @return boolean if a handler is found and detached
* @see on()
*/
public function off($name, $handler = null)
{
$this->ensureBehaviors();
if (isset($this->_events[$name])) {
if ($handler === null) {
$this->_events[$name] = array();
} else {
$removed = false;
foreach ($this->_events[$name] as $i => $event) {
if ($event[0] === $handler) {
unset($this->_events[$name][$i]);
$removed = true;
}
}
if ($removed) {
$this->_events[$name] = array_values($this->_events[$name]);
}
return $removed;
}
}
return false;
}
/**
* Triggers an event.
* This method represents the happening of an event. It invokes
* all attached handlers for the event.
* @param string $name the event name
* @param Event $event the event parameter. If not set, a default [[Event]] object will be created.
*/
public function trigger($name, $event = null)
{
$this->ensureBehaviors();
if (!empty($this->_events[$name])) {
if ($event === null) {
$event = new Event;
}
if ($event->sender === null) {
$event->sender = $this;
}
$event->handled = false;
$event->name = $name;
foreach ($this->_events[$name] as $handler) {
$event->data = $handler[1];
call_user_func($handler[0], $event);
// stop further handling if the event is handled
if ($event instanceof Event && $event->handled) {
return;
}
}
}
}
/**
* Returns the named behavior object.
* @param string $name the behavior name
* @return Behavior the behavior object, or null if the behavior does not exist
*/
public function getBehavior($name)
{
$this->ensureBehaviors();
return isset($this->_behaviors[$name]) ? $this->_behaviors[$name] : null;
}
/**
* Returns all behaviors attached to this component.
* @return Behavior[] list of behaviors attached to this component
*/
public function getBehaviors()
{
$this->ensureBehaviors();
return $this->_behaviors;
}
/**
* 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 attached to
* this component by calling the [[Behavior::attach()]] method.
* @param string $name the name of the behavior.
* @param string|array|Behavior $behavior the behavior configuration. This can be one of the following:
*
* - a [[Behavior]] object
* - a string specifying the behavior class
* - an object configuration array that will be passed to [[Yii::createObject()]] to create the behavior object.
*
* @return Behavior the behavior object
* @see detachBehavior
*/
public function attachBehavior($name, $behavior)
{
$this->ensureBehaviors();
return $this->attachBehaviorInternal($name, $behavior);
}
/**
* Attaches a list of behaviors to the component.
* Each behavior is indexed by its name and should be a [[Behavior]] object,
* a string specifying the behavior class, or an configuration array for creating the behavior.
* @param array $behaviors list of behaviors to be attached to the component
* @see attachBehavior
*/
public function attachBehaviors($behaviors)
{
$this->ensureBehaviors();
foreach ($behaviors as $name => $behavior) {
$this->attachBehaviorInternal($name, $behavior);
}
}
/**
* Detaches a behavior from the component.
* The behavior's [[Behavior::detach()]] method will be invoked.
* @param string $name the behavior's name.
* @return Behavior the detached behavior. Null if the behavior does not exist.
*/
public function detachBehavior($name)
{
$this->ensureBehaviors();
if (isset($this->_behaviors[$name])) {
$behavior = $this->_behaviors[$name];
unset($this->_behaviors[$name]);
$behavior->detach();
return $behavior;
} else {
return null;
}
}
/**
* Detaches all behaviors from the component.
*/
public function detachBehaviors()
{
$this->ensureBehaviors();
if ($this->_behaviors !== null) {
foreach ($this->_behaviors as $name => $behavior) {
$this->detachBehavior($name);
}
}
$this->_behaviors = array();
}
/**
* Makes sure that the behaviors declared in [[behaviors()]] are attached to this component.
*/
public function ensureBehaviors()
{
if ($this->_behaviors === null) {
$this->_behaviors = array();
foreach ($this->behaviors() as $name => $behavior) {
$this->attachBehaviorInternal($name, $behavior);
}
}
}
/**
* Attaches a behavior to this component.
* @param string $name the name of the behavior.
* @param string|array|Behavior $behavior the behavior to be attached
* @return Behavior the attached behavior.
*/
private function attachBehaviorInternal($name, $behavior)
{
if (!($behavior instanceof Behavior)) {
$behavior = Yii::createObject($behavior);
}
if (isset($this->_behaviors[$name])) {
$this->_behaviors[$name]->detach();
}
$behavior->attach($this);
return $this->_behaviors[$name] = $behavior;
}
}