Subversion-Projekte lars-tiefland.prado

<?php
/**
 * TControl, TControlCollection, TEventParameter and INamingContainer class file
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2008 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 */

/**
 * Includes TAttributeCollection and TControlAdapter class
 */
Prado::using('System.Collections.TAttributeCollection');
Prado::using('System.Web.UI.TControlAdapter');

/**
 * TControl class
 *
 * TControl is the base class for all components on a page hierarchy.
 * It implements the following features for UI-related functionalities:
 * - databinding feature
 * - parent and child relationship
 * - naming container and containee relationship
 * - viewstate and controlstate features
 * - rendering scheme
 * - control lifecycles
 *
 * A property can be data-bound with an expression. By calling {@link dataBind},
 * expressions bound to properties will be evaluated and the results will be
 * set to the corresponding properties.
 *
 * Parent and child relationship determines how the presentation of controls are
 * enclosed within each other. A parent will determine where to place
 * the presentation of its child controls. For example, a TPanel will enclose
 * all its child controls' presentation within a div html tag. A control's parent
 * can be obtained via {@link getParent Parent} property, and its
 * {@link getControls Controls} property returns a list of the control's children,
 * including controls and static texts. The property can be manipulated
 * like an array for adding or removing a child (see {@link TList} for more details).
 *
 * A naming container control implements INamingContainer and ensures that
 * its containee controls can be differentiated by their ID property values.
 * Naming container and containee realtionship specifies a protocol to uniquely
 * identify an arbitrary control on a page hierarchy by an ID path (concatenation
 * of all naming containers' IDs and the target control's ID).
 *
 * Viewstate and controlstate are two approaches to preserve state across
 * page postback requests. ViewState is mainly related with UI specific state
 * and can be disabled if not needed. ControlState represents crucial logic state
 * and cannot be disabled.
 *
 * A control is rendered via its {@link render()} method (the method is invoked
 * by the framework.) Descendant control classes may override this method for
 * customized rendering. By default, {@link render()} invokes {@link renderChildren()}
 * which is responsible for rendering of children of the control.
 * Control's {@link getVisible Visible} property governs whether the control
 * should be rendered or not.
 *
 * Each control on a page will undergo a series of lifecycles, including
 * control construction, Init, Load, PreRender, Render, and OnUnload.
 * They work together with page lifecycles to process a page request.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TControl extends TApplicationComponent implements IRenderable, IBindable
{
        /**
         * format of control ID
         */
        const ID_FORMAT='/^[a-zA-Z_]\\w*$/';
        /**
         * separator char between IDs in a UniqueID
         */
        const ID_SEPARATOR='$';
        /**
         * separator char between IDs in a ClientID
         */
        const CLIENT_ID_SEPARATOR='_';
        /**
         * prefix to an ID automatically generated
         */
        const AUTOMATIC_ID_PREFIX='ctl';

        /**
         * the stage of lifecycles that the control is currently at
         */
        const CS_CONSTRUCTED=0;
        const CS_CHILD_INITIALIZED=1;
        const CS_INITIALIZED=2;
        const CS_STATE_LOADED=3;
        const CS_LOADED=4;
        const CS_PRERENDERED=5;

        /**
         * State bits.
         */
        const IS_ID_SET=0x01;
        const IS_DISABLE_VIEWSTATE=0x02;
        const IS_SKIN_APPLIED=0x04;
        const IS_STYLESHEET_APPLIED=0x08;
        const IS_DISABLE_THEMING=0x10;
        const IS_CHILD_CREATED=0x20;
        const IS_CREATING_CHILD=0x40;

        /**
         * Indexes for the rare fields.
         * In order to save memory, rare fields will only be created if they are needed.
         */
        const RF_CONTROLS=0;                    // child controls
        const RF_CHILD_STATE=1;                 // child state field
        const RF_NAMED_CONTROLS=2;              // list of controls whose namingcontainer is this control
        const RF_NAMED_CONTROLS_ID=3;   // counter for automatic id
        const RF_SKIN_ID=4;                             // skin ID
        const RF_DATA_BINDINGS=5;               // data bindings
        const RF_EVENTS=6;                              // event handlers
        const RF_CONTROLSTATE=7;                // controlstate
        const RF_NAMED_OBJECTS=8;               // controls declared with ID on template
        const RF_ADAPTER=9;                             // adapter
        const RF_AUTO_BINDINGS=10;              // auto data bindings

        /**
         * @var string control ID
         */
        private $_id='';
        /**
         * @var string control unique ID
         */
        private $_uid;
        /**
         * @var TControl parent of the control
         */
        private $_parent;
        /**
         * @var TPage page that the control resides in
         */
        private $_page;
        /**
         * @var TControl naming container of the control
         */
        private $_namingContainer;
        /**
         * @var TTemplateControl control whose template contains the control
         */
        private $_tplControl;
        /**
         * @var array viewstate data
         */
        private $_viewState=array();
        /**
         * @var array temporary state (usually set in template)
         */
        private $_tempState=array();
        /**
         * @var boolean whether we should keep state in viewstate
         */
        private $_trackViewState=true;
        /**
         * @var integer the current stage of the control lifecycles
         */
        private $_stage=0;
        /**
         * @var integer representation of the state bits
         */
        private $_flags=0;
        /**
         * @var array a collection of rare control data
         */
        private $_rf=array();

        /**
         * Constructor.
         */
        public function __construct()
        {
        }

        /**
         * Returns a property value by name or a control by ID.
         * This overrides the parent implementation by allowing accessing
         * a control via its ID using the following syntax,
         * <code>
         * $menuBar=$this->menuBar;
         * </code>
         * Note, the control must be configured in the template
         * with explicit ID. If the name matches both a property and a control ID,
         * the control ID will take the precedence.
         *
         * @param string the property name or control ID
         * @return mixed the property value or the target control
         * @throws TInvalidOperationException if the property is not defined.
         * @see registerObject
         */
        public function __get($name)
        {
                if(isset($this->_rf[self::RF_NAMED_OBJECTS][$name]))
                        return $this->_rf[self::RF_NAMED_OBJECTS][$name];
                else
                        return parent::__get($name);
        }

        /**
         * @return boolean whether there is an adapter for this control
         */
        public function getHasAdapter()
        {
                return isset($this->_rf[self::RF_ADAPTER]);
        }

        /**
         * @return TControlAdapter control adapter. Null if not exists.
         */
        public function getAdapter()
        {
                return isset($this->_rf[self::RF_ADAPTER])?$this->_rf[self::RF_ADAPTER]:null;
        }

        /**
         * @param TControlAdapter control adapter
         */
        public function setAdapter(TControlAdapter $adapter)
        {
                $this->_rf[self::RF_ADAPTER]=$adapter;
        }

        /**
         * @return TControl the parent of this control
         */
        public function getParent()
        {
                return $this->_parent;
        }

        /**
         * @return TControl the naming container of this control
         */
        public function getNamingContainer()
        {
                if(!$this->_namingContainer && $this->_parent)
                {
                        if($this->_parent instanceof INamingContainer)
                                $this->_namingContainer=$this->_parent;
                        else
                                $this->_namingContainer=$this->_parent->getNamingContainer();
                }
                return $this->_namingContainer;
        }

        /**
         * @return TPage the page that contains this control
         */
        public function getPage()
        {
                if(!$this->_page)
                {
                        if($this->_parent)
                                $this->_page=$this->_parent->getPage();
                        else if($this->_tplControl)
                                $this->_page=$this->_tplControl->getPage();
                }
                return $this->_page;
        }

        /**
         * Sets the page for a control.
         * Only framework developers should use this method.
         * @param TPage the page that contains this control
         */
        public function setPage($page)
        {
                $this->_page=$page;
        }

        /**
         * Sets the control whose template contains this control.
         * Only framework developers should use this method.
         * @param TTemplateControl the control whose template contains this control
         */
        public function setTemplateControl($control)
        {
                $this->_tplControl=$control;
        }

        /**
         * @return TTemplateControl the control whose template contains this control
         */
        public function getTemplateControl()
        {
                if(!$this->_tplControl && $this->_parent)
                        $this->_tplControl=$this->_parent->getTemplateControl();
                return $this->_tplControl;
        }

        /**
         * @return TTemplateControl the control whose template is loaded from
         * some external storage, such as file, db, and whose template ultimately
         * contains this control.
         */
        public function getSourceTemplateControl()
        {
                $control=$this;
                while(($control instanceof TControl) && ($control=$control->getTemplateControl())!==null)
                {
                        if(($control instanceof TTemplateControl) && $control->getIsSourceTemplateControl())
                                return $control;
                }
                return $this->getPage();
        }

        /**
         * Gets the lifecycle step the control is currently at.
         * This method should only be used by control developers.
         * @return integer the lifecycle step the control is currently at.
         * The value can be CS_CONSTRUCTED, CS_CHILD_INITIALIZED, CS_INITIALIZED,
         * CS_STATE_LOADED, CS_LOADED, CS_PRERENDERED.
         */
        protected function getControlStage()
        {
                return $this->_stage;
        }

        /**
         * Sets the lifecycle step the control is currently at.
         * This method should only be used by control developers.
         * @param integer the lifecycle step the control is currently at.
         * Valid values include CS_CONSTRUCTED, CS_CHILD_INITIALIZED, CS_INITIALIZED,
         * CS_STATE_LOADED, CS_LOADED, CS_PRERENDERED.
         */
        protected function setControlStage($value)
        {
                $this->_stage=$value;
        }

        /**
         * Returns the id of the control.
         * Control ID can be either manually set or automatically generated.
         * If $hideAutoID is true, automatically generated ID will be returned as an empty string.
         * @param boolean whether to hide automatically generated ID
         * @return string the ID of the control
         */
        public function getID($hideAutoID=true)
        {
                if($hideAutoID)
                        return ($this->_flags & self::IS_ID_SET) ? $this->_id : '';
                else
                        return $this->_id;
        }

        /**
         * @param string the new control ID. The value must consist of word characters [a-zA-Z0-9_] only
         * @throws TInvalidDataValueException if ID is in a bad format
         */
        public function setID($id)
        {
                if(!preg_match(self::ID_FORMAT,$id))
                        throw new TInvalidDataValueException('control_id_invalid',get_class($this),$id);
                $this->_id=$id;
                $this->_flags |= self::IS_ID_SET;
                $this->clearCachedUniqueID($this instanceof INamingContainer);
                if($this->_namingContainer)
                        $this->_namingContainer->clearNameTable();
        }

        /**
         * Returns a unique ID that identifies the control in the page hierarchy.
         * A unique ID is the contenation of all naming container controls' IDs and the control ID.
         * These IDs are separated by '$' character.
         * Control users should not rely on the specific format of UniqueID, however.
         * @return string a unique ID that identifies the control in the page hierarchy
         */
        public function getUniqueID()
        {
                if($this->_uid==='' || $this->_uid===null)      // need to build the UniqueID
                {
                        $this->_uid='';  // set to not-null, so that clearCachedUniqueID() may take action
                        if($namingContainer=$this->getNamingContainer())
                        {
                                if($this->getPage()===$namingContainer)
                                        return ($this->_uid=$this->_id);
                                else if(($prefix=$namingContainer->getUniqueID())==='')
                                        return $this->_id;
                                else
                                        return ($this->_uid=$prefix.self::ID_SEPARATOR.$this->_id);
                        }
                        else    // no naming container
                                return $this->_id;
                }
                else
                        return $this->_uid;
        }

        /**
         * Sets input focus to this control.
         */
        public function focus()
        {
                $this->getPage()->setFocus($this);
        }

        /**
         * Returns the client ID of the control.
         * The client ID can be used to uniquely identify
         * the control in client-side scripts (such as JavaScript).
         * Do not rely on the explicit format of the return ID.
         * @return string the client ID of the control
         */
        public function getClientID()
        {
                return strtr($this->getUniqueID(),self::ID_SEPARATOR,self::CLIENT_ID_SEPARATOR);
        }

        /**
         * Converts a unique ID to a client ID.
         * @param string the unique ID of a control
         * @return string the client ID of the control
         */
        public static function convertUniqueIdToClientId($uniqueID)
        {
                return strtr($uniqueID,self::ID_SEPARATOR,self::CLIENT_ID_SEPARATOR);
        }

        /**
         * @return string the skin ID of this control, '' if not set
         */
        public function getSkinID()
        {
                return isset($this->_rf[self::RF_SKIN_ID])?$this->_rf[self::RF_SKIN_ID]:'';
        }

        /**
         * @param string the skin ID of this control
         * @throws TInvalidOperationException if the SkinID is set in a stage later than PreInit, or if the skin is applied already.
         */
        public function setSkinID($value)
        {
                if(($this->_flags & self::IS_SKIN_APPLIED) || $this->_stage>=self::CS_CHILD_INITIALIZED)
                        throw new TInvalidOperationException('control_skinid_unchangeable',get_class($this));
                else
                        $this->_rf[self::RF_SKIN_ID]=$value;
        }

        /**
         * @return boolean whether theming is enabled for this control.
         * The theming is enabled if the control and all its parents have it enabled.
         */
        public function getEnableTheming()
        {
                if($this->_flags & self::IS_DISABLE_THEMING)
                        return false;
                else
                        return $this->_parent?$this->_parent->getEnableTheming():true;
        }

        /**
         * @param boolean whether to enable theming
         * @throws TInvalidOperationException if this method is invoked after OnPreInit
         */
        public function setEnableTheming($value)
        {
                if($this->_stage>=self::CS_CHILD_INITIALIZED)
                        throw new TInvalidOperationException('control_enabletheming_unchangeable',get_class($this),$this->getUniqueID());
                else if(TPropertyValue::ensureBoolean($value))
                        $this->_flags &= ~self::IS_DISABLE_THEMING;
                else
                        $this->_flags |= self::IS_DISABLE_THEMING;
        }

        /**
         * Returns custom data associated with this control.
         * A control may be associated with some custom data for various purposes.
         * For example, a button may be associated with a string to identify itself
         * in a generic OnClick event handler.
         * @return mixed custom data associated with this control. Defaults to null.
         */
        public function getCustomData()
        {
                return $this->getViewState('CustomData',null);
        }

        /**
         * Associates custom data with this control.
         * Note, the custom data must be serializable and unserializable.
         * @param mixed custom data
         */
        public function setCustomData($value)
        {
                $this->setViewState('CustomData',$value,null);
        }

        /**
         * @return boolean whether the control has child controls
         */
        public function getHasControls()
        {
                return isset($this->_rf[self::RF_CONTROLS]) && $this->_rf[self::RF_CONTROLS]->getCount()>0;
        }

        /**
         * @return TControlCollection the child control collection
         */
        public function getControls()
        {
                if(!isset($this->_rf[self::RF_CONTROLS]))
                        $this->_rf[self::RF_CONTROLS]=$this->createControlCollection();
                return $this->_rf[self::RF_CONTROLS];
        }

        /**
         * Creates a control collection object that is to be used to hold child controls
         * @return TControlCollection control collection
         * @see getControls
         */
        protected function createControlCollection()
        {
                return $this->getAllowChildControls()?new TControlCollection($this):new TEmptyControlCollection($this);
        }

        /**
         * Checks if a control is visible.
         * If parent check is required, then a control is visible only if the control
         * and all its ancestors are visible.
         * @param boolean whether the parents should also be checked if visible
         * @return boolean whether the control is visible (default=true).
         */
        public function getVisible($checkParents=true)
        {
                if($checkParents)
                {
                        for($control=$this;$control;$control=$control->_parent)
                                if(!$control->getVisible(false))
                                        return false;
                        return true;
                }
                else
                        return $this->getViewState('Visible',true);
        }

        /**
         * @param boolean whether the control is visible
         */
        public function setVisible($value)
        {
                $this->setViewState('Visible',TPropertyValue::ensureBoolean($value),true);
        }

        /**
         * Returns a value indicating whether the control is enabled.
         * A control is enabled if it allows client user interaction.
         * If $checkParents is true, all parent controls will be checked,
         * and unless they are all enabled, false will be returned.
         * The property Enabled is mainly used for {@link TWebControl}
         * derived controls.
         * @param boolean whether the parents should also be checked enabled
         * @return boolean whether the control is enabled.
         */
        public function getEnabled($checkParents=false)
        {
                if($checkParents)
                {
                        for($control=$this;$control;$control=$control->_parent)
                                if(!$control->getViewState('Enabled',true))
                                        return false;
                        return true;
                }
                else
                        return $this->getViewState('Enabled',true);
        }

        /**
         * @param boolean whether the control is to be enabled.
         */
        public function setEnabled($value)
        {
                $this->setViewState('Enabled',TPropertyValue::ensureBoolean($value),true);
        }

        /**
         * @return boolean whether the control has custom attributes
         */
        public function getHasAttributes()
        {
                if($attributes=$this->getViewState('Attributes',null))
                        return $attributes->getCount()>0;
                else
                        return false;
        }

        /**
         * Returns the list of custom attributes.
         * Custom attributes are name-value pairs that may be rendered
         * as HTML tags' attributes.
         * @return TAttributeCollection the list of custom attributes
         */
        public function getAttributes()
        {
                if($attributes=$this->getViewState('Attributes',null))
                        return $attributes;
                else
                {
                        $attributes=new TAttributeCollection;
                        $this->setViewState('Attributes',$attributes,null);
                        return $attributes;
                }
        }

        /**
         * @return boolean whether the named attribute exists
         */
        public function hasAttribute($name)
        {
                if($attributes=$this->getViewState('Attributes',null))
                        return $attributes->contains($name);
                else
                        return false;
        }

        /**
         * @return string attribute value, null if attribute does not exist
         */
        public function getAttribute($name)
        {
                if($attributes=$this->getViewState('Attributes',null))
                        return $attributes->itemAt($name);
                else
                        return null;
        }

        /**
         * Sets a custom control attribute.
         * @param string attribute name
         * @param string value of the attribute
         */
        public function setAttribute($name,$value)
        {
                $this->getAttributes()->add($name,$value);
        }

        /**
         * Removes the named attribute.
         * @param string the name of the attribute to be removed.
         * @return string attribute value removed, null if attribute does not exist.
         */
        public function removeAttribute($name)
        {
                if($attributes=$this->getViewState('Attributes',null))
                        return $attributes->remove($name);
                else
                        return null;
        }

        /**
         * @return boolean whether viewstate is enabled
         */
        public function getEnableViewState($checkParents=false)
        {
                if($checkParents)
                {
                        for($control=$this;$control!==null;$control=$control->getParent())
                                if($control->_flags & self::IS_DISABLE_VIEWSTATE)
                                        return false;
                        return true;
                }
                else
                        return !($this->_flags & self::IS_DISABLE_VIEWSTATE);
        }

        /**
         * @param boolean set whether to enable viewstate
         */
        public function setEnableViewState($value)
        {
                if(TPropertyValue::ensureBoolean($value))
                        $this->_flags &= ~self::IS_DISABLE_VIEWSTATE;
                else
                        $this->_flags |= self::IS_DISABLE_VIEWSTATE;
        }

        /**
         * Returns a controlstate value.
         *
         * This function is mainly used in defining getter functions for control properties
         * that must be kept in controlstate.
         * @param string the name of the controlstate value to be returned
         * @param mixed the default value. If $key is not found in controlstate, $defaultValue will be returned
         * @return mixed the controlstate value corresponding to $key
         */
        protected function getControlState($key,$defaultValue=null)
        {
                return isset($this->_rf[self::RF_CONTROLSTATE][$key])?$this->_rf[self::RF_CONTROLSTATE][$key]:$defaultValue;
        }

        /**
         * Sets a controlstate value.
         *
         * This function is very useful in defining setter functions for control properties
         * that must be kept in controlstate.
         * Make sure that the controlstate value must be serializable and unserializable.
         * @param string the name of the controlstate value
         * @param mixed the controlstate value to be set
         * @param mixed default value. If $value===$defaultValue, the item will be cleared from controlstate
         */
        protected function setControlState($key,$value,$defaultValue=null)
        {
                if($value===$defaultValue)
                        unset($this->_rf[self::RF_CONTROLSTATE][$key]);
                else
                        $this->_rf[self::RF_CONTROLSTATE][$key]=$value;
        }

        /**
         * Clears a controlstate value.
         * @param string the name of the controlstate value to be cleared
         */
        protected function clearControlState($key)
        {
                unset($this->_rf[self::RF_CONTROLSTATE][$key]);
        }

        /**
         * Sets a value indicating whether we should keep data in viewstate.
         * When it is false, data saved via setViewState() will not be persisted.
         * By default, it is true, meaning data will be persisted across postbacks.
         * @param boolean whether data should be persisted
         */
        public function trackViewState($enabled)
        {
                $this->_trackViewState=TPropertyValue::ensureBoolean($enabled);
        }

        /**
         * Returns a viewstate value.
         *
         * This function is very useful in defining getter functions for component properties
         * that must be kept in viewstate.
         * @param string the name of the viewstate value to be returned
         * @param mixed the default value. If $key is not found in viewstate, $defaultValue will be returned
         * @return mixed the viewstate value corresponding to $key
         */
        public function getViewState($key,$defaultValue=null)
        {
                if(isset($this->_viewState[$key]))
                        return $this->_viewState[$key]!==null?$this->_viewState[$key]:$defaultValue;
                else if(isset($this->_tempState[$key]))
                {
                        if(is_object($this->_tempState[$key]) && $this->_trackViewState)
                                $this->_viewState[$key]=$this->_tempState[$key];
                        return $this->_tempState[$key];
                }
                else
                        return $defaultValue;
        }

        /**
         * Sets a viewstate value.
         *
         * This function is very useful in defining setter functions for control properties
         * that must be kept in viewstate.
         * Make sure that the viewstate value must be serializable and unserializable.
         * @param string the name of the viewstate value
         * @param mixed the viewstate value to be set
         * @param mixed default value. If $value===$defaultValue, the item will be cleared from the viewstate.
         */
        public function setViewState($key,$value,$defaultValue=null)
        {
                if($this->_trackViewState)
                {
                        $this->_viewState[$key]=$value;
                        unset($this->_tempState[$key]);
                }
                else
                {
                        unset($this->_viewState[$key]);
                        $this->_tempState[$key]=$value;
                }
        }

        /**
         * Clears a viewstate value.
         * @param string the name of the viewstate value to be cleared
         */
        public function clearViewState($key)
        {
                unset($this->_viewState[$key]);
                unset($this->_tempState[$key]);
        }

        /**
         * Sets up the binding between a property (or property path) and an expression.
         * The context of the expression is the template control (or the control itself if it is a page).
         * @param string the property name, or property path
         * @param string the expression
         */
        public function bindProperty($name,$expression)
        {
                $this->_rf[self::RF_DATA_BINDINGS][$name]=$expression;
        }

        /**
         * Breaks the binding between a property (or property path) and an expression.
         * @param string the property name (or property path)
         */
        public function unbindProperty($name)
        {
                unset($this->_rf[self::RF_DATA_BINDINGS][$name]);
        }

        /**
         * Sets up the binding between a property (or property path) and an expression.
         * Unlike regular databinding, the expression bound by this method
         * is automatically evaluated during {@link prerenderRecursive()}.
         * The context of the expression is the template control (or the control itself if it is a page).
         * @param string the property name, or property path
         * @param string the expression
         */
        public function autoBindProperty($name,$expression)
        {
                $this->_rf[self::RF_AUTO_BINDINGS][$name]=$expression;
        }

        /**
         * Performs the databinding for this control.
         */
        public function dataBind()
        {
                $this->dataBindProperties();
                $this->onDataBinding(null);
                $this->dataBindChildren();
        }

        /**
         * Databinding properties of the control.
         */
        protected function dataBindProperties()
        {
                Prado::trace("Data bind properties",'System.Web.UI.TControl');
                if(isset($this->_rf[self::RF_DATA_BINDINGS]))
                {
                        if(($context=$this->getTemplateControl())===null)
                                $context=$this;
                        foreach($this->_rf[self::RF_DATA_BINDINGS] as $property=>$expression)
                                $this->setSubProperty($property,$context->evaluateExpression($expression));
                }
        }

        /**
         * Auto databinding properties of the control.
         */
        protected function autoDataBindProperties()
        {
                if(isset($this->_rf[self::RF_AUTO_BINDINGS]))
                {
                        if(($context=$this->getTemplateControl())===null)
                                $context=$this;
                        foreach($this->_rf[self::RF_AUTO_BINDINGS] as $property=>$expression)
                                $this->setSubProperty($property,$context->evaluateExpression($expression));
                }
        }

        /**
         * Databinding child controls.
         */
        protected function dataBindChildren()
        {
                Prado::trace("dataBindChildren()",'System.Web.UI.TControl');
                if(isset($this->_rf[self::RF_CONTROLS]))
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                                if($control instanceof IBindable)
                                        $control->dataBind();
                }
        }

        /**
         * @return boolean whether child controls have been created
         */
        final protected function getChildControlsCreated()
        {
                return ($this->_flags & self::IS_CHILD_CREATED)!==0;
        }

        /**
         * Sets a value indicating whether child controls are created.
         * If false, any existing child controls will be cleared up.
         * @param boolean whether child controls are created
         */
        final protected function setChildControlsCreated($value)
        {
                if($value)
                        $this->_flags |= self::IS_CHILD_CREATED;
                else
                {
                        if($this->getHasControls() && ($this->_flags & self::IS_CHILD_CREATED))
                                $this->getControls()->clear();
                        $this->_flags &= ~self::IS_CHILD_CREATED;
                }
        }

        /**
         * Ensures child controls are created.
         * If child controls are not created yet, this method will invoke
         * {@link createChildControls} to create them.
         */
        public function ensureChildControls()
        {
                if(!($this->_flags & self::IS_CHILD_CREATED) && !($this->_flags & self::IS_CREATING_CHILD))
                {
                        try
                        {
                                $this->_flags |= self::IS_CREATING_CHILD;
                                if(isset($this->_rf[self::RF_ADAPTER]))
                                        $this->_rf[self::RF_ADAPTER]->createChildControls();
                                else
                                        $this->createChildControls();
                                $this->_flags &= ~self::IS_CREATING_CHILD;
                                $this->_flags |= self::IS_CHILD_CREATED;
                        }
                        catch(Exception $e)
                        {
                                $this->_flags &= ~self::IS_CREATING_CHILD;
                                $this->_flags |= self::IS_CHILD_CREATED;
                                throw $e;
                        }
                }
        }

        /**
         * Creates child controls.
         * This method can be overriden for controls who want to have their controls.
         * Do not call this method directly. Instead, call {@link ensureChildControls}
         * to ensure child controls are created only once.
         */
        public function createChildControls()
        {
        }

        /**
         * Finds a control by ID path within the current naming container.
         * The current naming container is either the control itself
         * if it implements {@link INamingContainer} or the control's naming container.
         * The ID path is an ID sequence separated by {@link TControl::ID_SEPARATOR}.
         * For example, 'Repeater1.Item1.Button1' looks for a control with ID 'Button1'
         * whose naming container is 'Item1' whose naming container is 'Repeater1'.
         * @param string ID of the control to be looked up
         * @return TControl|null the control found, null if not found
         * @throws TInvalidDataValueException if a control's ID is found not unique within its naming container.
         */
        public function findControl($id)
        {
                $id=strtr($id,'.',self::ID_SEPARATOR);
                $container=($this instanceof INamingContainer)?$this:$this->getNamingContainer();
                if(!$container || !$container->getHasControls())
                        return null;
                if(!isset($container->_rf[self::RF_NAMED_CONTROLS]))
                {
                        $container->_rf[self::RF_NAMED_CONTROLS]=array();
                        $container->fillNameTable($container,$container->_rf[self::RF_CONTROLS]);
                }
                if(($pos=strpos($id,self::ID_SEPARATOR))===false)
                        return isset($container->_rf[self::RF_NAMED_CONTROLS][$id])?$container->_rf[self::RF_NAMED_CONTROLS][$id]:null;
                else
                {
                        $cid=substr($id,0,$pos);
                        $sid=substr($id,$pos+1);
                        if(isset($container->_rf[self::RF_NAMED_CONTROLS][$cid]))
                                return $container->_rf[self::RF_NAMED_CONTROLS][$cid]->findControl($sid);
                        else
                                return null;
                }
        }

        /**
         * Finds all child and grand-child controls that are of the specified type.
         * @param string the class name
         * @param boolean whether the type comparison is strict or not. If false, controls of the parent classes of the specified class will also be returned.
         * @return array list of controls found
         */
        public function findControlsByType($type,$strict=true)
        {
                $controls=array();
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if(is_object($control) && (get_class($control)===$type || (!$strict && ($control instanceof $type))))
                                        $controls[]=$control;
                                if(($control instanceof TControl) && $control->getHasControls())
                                        $controls=array_merge($controls,$control->findControlsByType($type,$strict));
                        }
                }
                return $controls;
        }

        /**
         * Finds all child and grand-child controls with the specified ID.
         * Note, this method is different from {@link findControl} in that
         * it searches through all controls that have this control as the ancestor
         * while {@link findcontrol} only searches through controls that have this
         * control as the direct naming container.
         * @param string the ID being looked for
         * @return array list of controls found
         */
        public function findControlsByID($id)
        {
                $controls=array();
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                {
                                        if($control->_id===$id)
                                                $controls[]=$control;
                                        $controls=array_merge($controls,$control->findControlsByID($id));
                                }
                        }
                }
                return $controls;
        }

        /**
         * Resets the control as a naming container.
         * Only framework developers should use this method.
         */
        public function clearNamingContainer()
        {
                unset($this->_rf[self::RF_NAMED_CONTROLS_ID]);
                $this->clearNameTable();
        }

        /**
         * Registers an object by a name.
         * A registered object can be accessed like a public member variable.
         * This method should only be used by framework and control developers.
         * @param string name of the object
         * @param object object to be declared
         * @see __get
         */
        public function registerObject($name,$object)
        {
                if(isset($this->_rf[self::RF_NAMED_OBJECTS][$name]))
                        throw new TInvalidOperationException('control_object_reregistered',$name);
                $this->_rf[self::RF_NAMED_OBJECTS][$name]=$object;
        }

        /**
         * Unregisters an object by name.
         * @param string name of the object
         * @see registerObject
         */
        public function unregisterObject($name)
        {
                unset($this->_rf[self::RF_NAMED_OBJECTS][$name]);
        }

        /**
         * @return boolean whether an object has been registered with the name
         * @see registerObject
         */
        public function isObjectRegistered($name)
        {
                return isset($this->_rf[self::RF_NAMED_OBJECTS][$name]);
        }

        /**
         * @return boolean true if the child control has been initialized.
         */
        public function getHasChildInitialized()
        {
                return $this->getControlStage() >= self::CS_CHILD_INITIALIZED;
        }

        /**
         * @return boolean true if the onInit event has raised.
         */
        public function getHasInitialized()
        {
                return $this->getControlStage() >= self::CS_INITIALIZED;
        }

        /**
         * @return boolean true if the control has loaded post data.
         */
        public function getHasLoadedPostData()
        {
                return $this->getControlStage() >= self::CS_STATE_LOADED;
        }

        /**
         * @return boolean true if the onLoad event has raised.
         */
        public function getHasLoaded()
        {
                return $this->getControlStage() >= self::CS_LOADED;
        }

        /**
         * @return boolean true if onPreRender event has raised.
         */
        public function getHasPreRendered()
        {
                return $this->getControlStage() >= self::CS_PRERENDERED;
        }

        /**
         * Returns the named registered object.
         * A component with explicit ID on a template will be registered to
         * the template owner. This method allows you to obtain this component
         * with the ID.
         * @return mixed the named registered object. Null if object is not found.
         */
        public function getRegisteredObject($name)
        {
                return isset($this->_rf[self::RF_NAMED_OBJECTS][$name])?$this->_rf[self::RF_NAMED_OBJECTS][$name]:null;
        }

        /**
         * @return boolean whether body contents are allowed for this control. Defaults to true.
         */
        public function getAllowChildControls()
        {
                return true;
        }

        /**
         * Adds the object instantiated on a template to the child control collection.
         * This method overrides the parent implementation.
         * Only framework developers and control developers should use this method.
         * @param string|TComponent text string or component parsed and instantiated in template
         * @see createdOnTemplate
         */
        public function addParsedObject($object)
        {
                $this->getControls()->add($object);
        }

        /**
         * Clears up the child state data.
         * After a control loads its state, those state that do not belong to
         * any existing child controls are stored as child state.
         * This method will remove these state.
         * Only frameworker developers and control developers should use this method.
         */
        final protected function clearChildState()
        {
                unset($this->_rf[self::RF_CHILD_STATE]);
        }

        /**
         * @param TControl the potential ancestor control
         * @return boolean if the control is a descendent (parent, parent of parent, etc.)
         * of the specified control
         */
        final protected function isDescendentOf($ancestor)
        {
                $control=$this;
                while($control!==$ancestor && $control->_parent)
                        $control=$control->_parent;
                return $control===$ancestor;
        }

        /**
         * Adds a control into the child collection of the control.
         * Control lifecycles will be caught up during the addition.
         * Only framework developers should use this method.
         * @param TControl the new child control
         */
        public function addedControl($control)
        {
                if($control->_parent)
                        $control->_parent->getControls()->remove($control);
                $control->_parent=$this;
                $control->_page=$this->getPage();
                $namingContainer=($this instanceof INamingContainer)?$this:$this->_namingContainer;
                if($namingContainer)
                {
                        $control->_namingContainer=$namingContainer;
                        if($control->_id==='')
                                $control->generateAutomaticID();
                        else
                                $namingContainer->clearNameTable();
                        $control->clearCachedUniqueID($control instanceof INamingContainer);
                }

                if($this->_stage>=self::CS_CHILD_INITIALIZED)
                {
                        $control->initRecursive($namingContainer);
                        if($this->_stage>=self::CS_STATE_LOADED)
                        {
                                if(isset($this->_rf[self::RF_CHILD_STATE][$control->_id]))
                                {
                                        $state=$this->_rf[self::RF_CHILD_STATE][$control->_id];
                                        unset($this->_rf[self::RF_CHILD_STATE][$control->_id]);
                                }
                                else
                                        $state=null;
                                $control->loadStateRecursive($state,!($this->_flags & self::IS_DISABLE_VIEWSTATE));
                                if($this->_stage>=self::CS_LOADED)
                                {
                                        $control->loadRecursive();
                                        if($this->_stage>=self::CS_PRERENDERED)
                                                $control->preRenderRecursive();
                                }
                        }
                }
        }

        /**
         * Removes a control from the child collection of the control.
         * Only framework developers should use this method.
         * @param TControl the child control removed
         */
        public function removedControl($control)
        {
                if($this->_namingContainer)
                        $this->_namingContainer->clearNameTable();
                $control->unloadRecursive();
                $control->_parent=null;
                $control->_page=null;
                $control->_namingContainer=null;
                $control->_tplControl=null;
                //$control->_stage=self::CS_CONSTRUCTED;
                if(!($control->_flags & self::IS_ID_SET))
                        $control->_id='';
                else
                        unset($this->_rf[self::RF_NAMED_OBJECTS][$control->_id]);
                $control->clearCachedUniqueID(true);
        }

        /**
         * Performs the Init step for the control and all its child controls.
         * Only framework developers should use this method.
         * @param TControl the naming container control
         */
        protected function initRecursive($namingContainer=null)
        {
                $this->ensureChildControls();
                if($this->getHasControls())
                {
                        if($this instanceof INamingContainer)
                                $namingContainer=$this;
                        $page=$this->getPage();
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                {
                                        $control->_namingContainer=$namingContainer;
                                        $control->_page=$page;
                                        if($control->_id==='' && $namingContainer)
                                                $control->generateAutomaticID();
                                        $control->initRecursive($namingContainer);
                                }
                        }
                }
                if($this->_stage<self::CS_INITIALIZED)
                {
                        $this->_stage=self::CS_CHILD_INITIALIZED;
                        if(($page=$this->getPage()) && $this->getEnableTheming() && !($this->_flags & self::IS_SKIN_APPLIED))
                        {
                                $page->applyControlSkin($this);
                                $this->_flags |= self::IS_SKIN_APPLIED;
                        }
                        if(isset($this->_rf[self::RF_ADAPTER]))
                                $this->_rf[self::RF_ADAPTER]->onInit(null);
                        else
                                $this->onInit(null);
                        $this->_stage=self::CS_INITIALIZED;
                }
        }

        /**
         * Performs the Load step for the control and all its child controls.
         * Only framework developers should use this method.
         */
        protected function loadRecursive()
        {
                if($this->_stage<self::CS_LOADED)
                {
                        if(isset($this->_rf[self::RF_ADAPTER]))
                                $this->_rf[self::RF_ADAPTER]->onLoad(null);
                        else
                                $this->onLoad(null);
                }
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                        $control->loadRecursive();
                        }
                }
                if($this->_stage<self::CS_LOADED)
                        $this->_stage=self::CS_LOADED;
        }

        /**
         * Performs the PreRender step for the control and all its child controls.
         * Only framework developers should use this method.
         */
        protected function preRenderRecursive()
        {
                $this->autoDataBindProperties();

                if($this->getVisible(false))
                {
                        if(isset($this->_rf[self::RF_ADAPTER]))
                                $this->_rf[self::RF_ADAPTER]->onPreRender(null);
                        else
                                $this->onPreRender(null);
                        if($this->getHasControls())
                        {
                                foreach($this->_rf[self::RF_CONTROLS] as $control)
                                {
                                        if($control instanceof TControl)
                                                $control->preRenderRecursive();
                                        else if($control instanceof TCompositeLiteral)
                                                $control->evaluateDynamicContent();
                                }
                        }
                        $this->addToPostDataLoader();
                }
                $this->_stage=self::CS_PRERENDERED;
        }

        /**
         * Add controls implementing IPostBackDataHandler to post data loaders.
         */
        protected function addToPostDataLoader()
        {
                if($this instanceof IPostBackDataHandler)
                        $this->getPage()->registerPostDataLoader($this);
        }

        /**
         * Performs the Unload step for the control and all its child controls.
         * Only framework developers should use this method.
         */
        protected function unloadRecursive()
        {
                if(!($this->_flags & self::IS_ID_SET))
                        $this->_id='';
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                                if($control instanceof TControl)
                                        $control->unloadRecursive();
                }
                if(isset($this->_rf[self::RF_ADAPTER]))
                        $this->_rf[self::RF_ADAPTER]->onUnload(null);
                else
                        $this->onUnload(null);
        }

        /**
         * This method is invoked when the control enters 'OnInit' stage.
         * The method raises 'OnInit' event.
         * If you override this method, be sure to call the parent implementation
         * so that the event handlers can be invoked.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onInit($param)
        {
                $this->raiseEvent('OnInit',$this,$param);
        }

        /**
         * This method is invoked when the control enters 'OnLoad' stage.
         * The method raises 'OnLoad' event.
         * If you override this method, be sure to call the parent implementation
         * so that the event handlers can be invoked.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onLoad($param)
        {
                $this->raiseEvent('OnLoad',$this,$param);
        }

        /**
         * Raises 'OnDataBinding' event.
         * This method is invoked when {@link dataBind} is invoked.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onDataBinding($param)
        {
                Prado::trace("onDataBinding()",'System.Web.UI.TControl');
                $this->raiseEvent('OnDataBinding',$this,$param);
        }


        /**
         * This method is invoked when the control enters 'OnUnload' stage.
         * The method raises 'OnUnload' event.
         * If you override this method, be sure to call the parent implementation
         * so that the event handlers can be invoked.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onUnload($param)
        {
                $this->raiseEvent('OnUnload',$this,$param);
        }

        /**
         * This method is invoked when the control enters 'OnPreRender' stage.
         * The method raises 'OnPreRender' event.
         * If you override this method, be sure to call the parent implementation
         * so that the event handlers can be invoked.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onPreRender($param)
        {
                $this->raiseEvent('OnPreRender',$this,$param);
        }

        /**
         * Invokes the parent's bubbleEvent method.
         * A control who wants to bubble an event must call this method in its onEvent method.
         * @param TControl sender of the event
         * @param TEventParameter event parameter
         * @see bubbleEvent
         */
        protected function raiseBubbleEvent($sender,$param)
        {
                $control=$this;
                while($control=$control->_parent)
                {
                        if($control->bubbleEvent($sender,$param))
                                break;
                }
        }

        /**
         * This method responds to a bubbled event.
         * This method should be overriden to provide customized response to a bubbled event.
         * Check the type of event parameter to determine what event is bubbled currently.
         * @param TControl sender of the event
         * @param TEventParameter event parameters
         * @return boolean true if the event bubbling is handled and no more bubbling.
         * @see raiseBubbleEvent
         */
        public function bubbleEvent($sender,$param)
        {
                return false;
        }

        /**
         * Broadcasts an event.
         * The event will be sent to all controls on the current page hierarchy.
         * If a control defines the event, the event will be raised for the control.
         * If a control implements {@link IBroadcastEventReceiver}, its
         * {@link IBroadcastEventReceiver::broadcastEventReceived broadcastEventReceived()} method will
         * be invoked which gives the control a chance to respond to the event.
         * For example, when broadcasting event 'OnClick', all controls having 'OnClick'
         * event will have this event raised, and all controls implementing
         * {@link IBroadcastEventReceiver} will also have its
         * {@link IBroadcastEventReceiver::broadcastEventReceived broadcastEventReceived()}
         * invoked.
         * @param string name of the broadcast event
         * @param TControl sender of this event
         * @param TEventParameter event parameter
         */
        public function broadcastEvent($name,$sender,$param)
        {
                $rootControl=(($page=$this->getPage())===null)?$this:$page;
                $rootControl->broadcastEventInternal($name,$sender,new TBroadcastEventParameter($name,$param));
        }

        /**
         * Recursively broadcasts an event.
         * This method should only be used by framework developers.
         * @param string name of the broadcast event
         * @param TControl sender of the event
         * @param TBroadcastEventParameter event parameter
         */
        private function broadcastEventInternal($name,$sender,$param)
        {
                if($this->hasEvent($name))
                        $this->raiseEvent($name,$sender,$param->getParameter());
                if($this instanceof IBroadcastEventReceiver)
                        $this->broadcastEventReceived($sender,$param);
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                        $control->broadcastEventInternal($name,$sender,$param);
                        }
                }
        }

        /**
         * Traverse the whole control hierarchy rooted at this control.
         * Callback function may be invoked for each control being visited.
         * A pre-callback is invoked before traversing child controls;
         * A post-callback is invoked after traversing child controls.
         * Callback functions can be global functions or class methods.
         * They must be of the following signature:
         * <code>
         * function callback_func($control,$param) {...}
         * </code>
         * where $control refers to the control being visited and $param
         * is the parameter that is passed originally when calling this traverse function.
         *
         * @param mixed parameter to be passed to callbacks for each control
         * @param callback callback invoked before traversing child controls. If null, it is ignored.
         * @param callback callback invoked after traversing child controls. If null, it is ignored.
         */
        protected function traverseChildControls($param,$preCallback=null,$postCallback=null)
        {
                if($preCallback!==null)
                        call_user_func($preCallback,$this,$param);
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                {
                                        $control->traverseChildControls($param,$preCallback,$postCallback);
                                }
                        }
                }
                if($postCallback!==null)
                        call_user_func($postCallback,$this,$param);
        }

        /**
         * Renders the control.
         * Only when the control is visible will the control be rendered.
         * @param THtmlWriter the writer used for the rendering purpose
         */
        public function renderControl($writer)
        {
                if($this->getVisible(false))
                {
                        if(isset($this->_rf[self::RF_ADAPTER]))
                                $this->_rf[self::RF_ADAPTER]->render($writer);
                        else
                                $this->render($writer);
                }
        }

        /**
         * Renders the control.
         * This method is invoked by {@link renderControl} when the control is visible.
         * You can override this method to provide customized rendering of the control.
         * By default, the control simply renders all its child contents.
         * @param THtmlWriter the writer used for the rendering purpose
         */
        public function render($writer)
        {
                $this->renderChildren($writer);
        }

        /**
         * Renders the children of the control.
         * This method iterates through all child controls and static text strings
         * and renders them in order.
         * @param THtmlWriter the writer used for the rendering purpose
         */
        public function renderChildren($writer)
        {
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if(is_string($control))
                                        $writer->write($control);
                                else if($control instanceof TControl)
                                        $control->renderControl($writer);
                                else if($control instanceof IRenderable)
                                        $control->render($writer);
                        }
                }
        }

        /**
         * This method is invoked when control state is to be saved.
         * You can override this method to do last step state saving.
         * Parent implementation must be invoked.
         */
        public function saveState()
        {
        }

        /**
         * This method is invoked right after the control has loaded its state.
         * You can override this method to initialize data from the control state.
         * Parent implementation must be invoked.
         */
        public function loadState()
        {
        }

        /**
         * Loads state (viewstate and controlstate) into a control and its children.
         * This method should only be used by framework developers.
         * @param array the collection of the state
         * @param boolean whether the viewstate should be loaded
         */
        protected function loadStateRecursive(&$state,$needViewState=true)
        {
                if(is_array($state))
                {
                        // A null state means the stateful properties all take default values.
                        // So if the state is enabled, we have to assign the null value.
                        $needViewState=($needViewState && !($this->_flags & self::IS_DISABLE_VIEWSTATE));
                        if(isset($state[1]))
                        {
                                $this->_rf[self::RF_CONTROLSTATE]=&$state[1];
                                unset($state[1]);
                        }
                        else
                                unset($this->_rf[self::RF_CONTROLSTATE]);
                        if($needViewState)
                        {
                                if(isset($state[0]))
                                        $this->_viewState=&$state[0];
                                else
                                        $this->_viewState=array();
                        }
                        unset($state[0]);
                        if($this->getHasControls())
                        {
                                foreach($this->_rf[self::RF_CONTROLS] as $control)
                                {
                                        if($control instanceof TControl)
                                        {
                                                if(isset($state[$control->_id]))
                                                {
                                                        $control->loadStateRecursive($state[$control->_id],$needViewState);
                                                        unset($state[$control->_id]);
                                                }
                                        }
                                }
                        }
                        if(!empty($state))
                                $this->_rf[self::RF_CHILD_STATE]=&$state;
                }
                $this->_stage=self::CS_STATE_LOADED;
                if(isset($this->_rf[self::RF_ADAPTER]))
                        $this->_rf[self::RF_ADAPTER]->loadState();
                else
                        $this->loadState();
        }

        /**
         * Saves all control state (viewstate and controlstate) as a collection.
         * This method should only be used by framework developers.
         * @param boolean whether the viewstate should be saved
         * @return array the collection of the control state (including its children's state).
         */
        protected function &saveStateRecursive($needViewState=true)
        {
                if(isset($this->_rf[self::RF_ADAPTER]))
                        $this->_rf[self::RF_ADAPTER]->saveState();
                else
                        $this->saveState();
                $needViewState=($needViewState && !($this->_flags & self::IS_DISABLE_VIEWSTATE));
                $state=array();
                if($this->getHasControls())
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                        {
                                if($control instanceof TControl)
                                        $state[$control->_id]=&$control->saveStateRecursive($needViewState);
                        }
                }
                if($needViewState && !empty($this->_viewState))
                        $state[0]=&$this->_viewState;
                if(isset($this->_rf[self::RF_CONTROLSTATE]))
                        $state[1]=&$this->_rf[self::RF_CONTROLSTATE];
                return $state;
        }

        /**
         * Applies a stylesheet skin to a control.
         * @param TPage the page containing the control
         * @throws TInvalidOperationException if the stylesheet skin is applied already
         */
        public function applyStyleSheetSkin($page)
        {
                if($page && !($this->_flags & self::IS_STYLESHEET_APPLIED))
                {
                        $page->applyControlStyleSheet($this);
                        $this->_flags |= self::IS_STYLESHEET_APPLIED;
                }
                else if($this->_flags & self::IS_STYLESHEET_APPLIED)
                        throw new TInvalidOperationException('control_stylesheet_applied',get_class($this));
        }

        /**
         * Clears the cached UniqueID.
         * If $recursive=true, all children's cached UniqueID will be cleared as well.
         * @param boolean whether the clearing is recursive.
         */
        private function clearCachedUniqueID($recursive)
        {
                if($recursive && $this->_uid!==null && isset($this->_rf[self::RF_CONTROLS]))
                {
                        foreach($this->_rf[self::RF_CONTROLS] as $control)
                                if($control instanceof TControl)
                                        $control->clearCachedUniqueID($recursive);
                }
                $this->_uid=null;
        }

        /**
         * Generates an automatic ID for the control.
         */
        private function generateAutomaticID()
        {
                $this->_flags &= ~self::IS_ID_SET;
                if(!isset($this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]))
                        $this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]=0;
                $id=$this->_namingContainer->_rf[self::RF_NAMED_CONTROLS_ID]++;
                $this->_id=self::AUTOMATIC_ID_PREFIX . $id;
                $this->_namingContainer->clearNameTable();
        }

        /**
         * Clears the list of the controls whose IDs are managed by the specified naming container.
         */
        private function clearNameTable()
        {
                unset($this->_rf[self::RF_NAMED_CONTROLS]);
        }

        /**
         * Updates the list of the controls whose IDs are managed by the specified naming container.
         * @param TControl the naming container
         * @param TControlCollection list of controls
         * @throws TInvalidDataValueException if a control's ID is not unique within its naming container.
         */
        private function fillNameTable($container,$controls)
        {
                foreach($controls as $control)
                {
                        if($control instanceof TControl)
                        {
                                if($control->_id!=='')
                                {
                                        if(isset($container->_rf[self::RF_NAMED_CONTROLS][$control->_id]))
                                                throw new TInvalidDataValueException('control_id_nonunique',get_class($control),$control->_id);
                                        else
                                                $container->_rf[self::RF_NAMED_CONTROLS][$control->_id]=$control;
                                }
                                if(!($control instanceof INamingContainer) && $control->getHasControls())
                                        $this->fillNameTable($container,$control->_rf[self::RF_CONTROLS]);
                        }
                }
        }
}


/**
 * TControlCollection class
 *
 * TControlCollection implements a collection that enables
 * controls to maintain a list of their child controls.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TControlCollection extends TList
{
        /**
         * the control that owns this collection.
         * @var TControl
         */
        private $_o;

        /**
         * Constructor.
         * @param TControl the control that owns this collection.
         * @param boolean whether the list is read-only
         */
        public function __construct(TControl $owner,$readOnly=false)
        {
                $this->_o=$owner;
                parent::__construct(null,$readOnly);
        }

        /**
         * @return TControl the control that owns this collection.
         */
        protected function getOwner()
        {
                return $this->_o;
        }

        /**
         * Inserts an item at the specified position.
         * This overrides the parent implementation by performing additional
         * operations for each newly added child control.
         * @param integer the speicified position.
         * @param mixed new item
         * @throws TInvalidDataTypeException if the item to be inserted is neither a string nor a TControl.
         */
        public function insertAt($index,$item)
        {
                if($item instanceof TControl)
                {
                        parent::insertAt($index,$item);
                        $this->_o->addedControl($item);
                }
                else if(is_string($item) || ($item instanceof IRenderable))
                        parent::insertAt($index,$item);
                else
                        throw new TInvalidDataTypeException('controlcollection_control_required');
        }

        /**
         * Removes an item at the specified position.
         * This overrides the parent implementation by performing additional
         * cleanup work when removing a child control.
         * @param integer the index of the item to be removed.
         * @return mixed the removed item.
         */
        public function removeAt($index)
        {
                $item=parent::removeAt($index);
                if($item instanceof TControl)
                        $this->_o->removedControl($item);
                return $item;
        }

        /**
         * Overrides the parent implementation by invoking {@link TControl::clearNamingContainer}
         */
        public function clear()
        {
                parent::clear();
                if($this->_o instanceof INamingContainer)
                        $this->_o->clearNamingContainer();
        }
}

/**
 * TEmptyControlCollection class
 *
 * TEmptyControlCollection implements an empty control list that prohibits adding
 * controls to it. This is useful for controls that do not allow child controls.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TEmptyControlCollection extends TControlCollection
{
        /**
         * Constructor.
         * @param TControl the control that owns this collection.
         */
        public function __construct(TControl $owner)
        {
                parent::__construct($owner,true);
        }

        /**
         * Inserts an item at the specified position.
         * This overrides the parent implementation by ignoring new addition.
         * @param integer the speicified position.
         * @param mixed new item
         */
        public function insertAt($index,$item)
        {
                if(!is_string($item))  // string is possible if property tag is used. we simply ignore it in this case
                        parent::insertAt($index,$item);  // this will generate an exception in parent implementation
        }
}

/**
 * INamingContainer interface.
 * INamingContainer marks a control as a naming container.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface INamingContainer
{
}

/**
 * IPostBackEventHandler interface
 *
 * If a control wants to respond to postback event, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IPostBackEventHandler
{
        /**
         * Raises postback event.
         * The implementation of this function should raise appropriate event(s) (e.g. OnClick, OnCommand)
         * indicating the component is responsible for the postback event.
         * @param string the parameter associated with the postback event
         */
        public function raisePostBackEvent($param);
}

/**
 * IPostBackDataHandler interface
 *
 * If a control wants to load post data, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IPostBackDataHandler
{
        /**
         * Loads user input data.
         * The implementation of this function can use $values[$key] to get the user input
         * data that are meant for the particular control.
         * @param string the key that can be used to retrieve data from the input data collection
         * @param array the input data collection
         * @return boolean whether the data of the control has been changed
         */
        public function loadPostData($key,$values);
        /**
         * Raises postdata changed event.
         * The implementation of this function should raise appropriate event(s) (e.g. OnTextChanged)
         * indicating the control data is changed.
         */
        public function raisePostDataChangedEvent();
        /**
         * @return boolean whether postback causes the data change. Defaults to false for non-postback state.
         */
        public function getDataChanged();
}


/**
 * IValidator interface
 *
 * If a control wants to validate user input, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IValidator
{
        /**
         * Validates certain data.
         * The implementation of this function should validate certain data
         * (e.g. data entered into TTextBox control).
         * @return boolean whether the data passes the validation
         */
        public function validate();
        /**
         * @return boolean whether the previous {@link validate()} is successful.
         */
        public function getIsValid();
        /**
         * @param boolean whether the validator validates successfully
         */
        public function setIsValid($value);
        /**
         * @return string error message during last validate
         */
        public function getErrorMessage();
        /**
         * @param string error message for the validation
         */
        public function setErrorMessage($value);
}


/**
 * IValidatable interface
 *
 * If a control wants to be validated by a validator, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IValidatable
{
        /**
         * @return mixed the value of the property to be validated.
         */
        public function getValidationPropertyValue();
        /**
         * @return boolean wether this control's validators validated successfully (must default to true)
         */
        public function getIsValid();
        /**
         * @return boolean wether this control's validators validated successfully
         */
        public function setIsValid($value);
}

/**
 * IBroadcastEventReceiver interface
 *
 * If a control wants to check broadcast event, it must implement this interface.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IBroadcastEventReceiver
{
        /**
         * Handles broadcast event.
         * This method is invoked automatically when an event is broadcasted.
         * Within this method, you may check the event name given in
         * the event parameter to determine  whether you should respond to
         * this event.
         * @param TControl sender of the event
         * @param TBroadCastEventParameter event parameter
         */
        public function broadcastEventReceived($sender,$param);
}

/**
 * ITheme interface.
 *
 * This interface must be implemented by theme.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface ITheme
{
        /**
         * Applies this theme to the specified control.
         * @param TControl the control to be applied with this theme
         */
        public function applySkin($control);
}

/**
 * ITemplate interface
 *
 * ITemplate specifies the interface for classes encapsulating
 * parsed template structures.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface ITemplate
{
        /**
         * Instantiates the template.
         * Content in the template will be instantiated as components and text strings
         * and passed to the specified parent control.
         * @param TControl the parent control
         */
        public function instantiateIn($parent);
}

/**
 * IButtonControl interface
 *
 * IButtonControl specifies the common properties and events that must
 * be implemented by a button control, such as {@link TButton}, {@link TLinkButton},
 * {@link TImageButton}.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
interface IButtonControl
{
        /**
         * @return string caption of the button
         */
        public function getText();

        /**
         * @param string caption of the button
         */
        public function setText($value);

        /**
         * @return boolean whether postback event trigger by this button will cause input validation
         */
        public function getCausesValidation();

        /**
         * @param boolean whether postback event trigger by this button will cause input validation
         */
        public function setCausesValidation($value);

        /**
         * @return string the command name associated with the {@link onCommand OnCommand} event.
         */
        public function getCommandName();

        /**
         * @param string the command name associated with the {@link onCommand OnCommand} event.
         */
        public function setCommandName($value);

        /**
         * @return string the parameter associated with the {@link onCommand OnCommand} event
         */
        public function getCommandParameter();

        /**
         * @param string the parameter associated with the {@link onCommand OnCommand} event.
         */
        public function setCommandParameter($value);

        /**
         * @return string the group of validators which the button causes validation upon postback
         */
        public function getValidationGroup();

        /**
         * @param string the group of validators which the button causes validation upon postback
         */
        public function setValidationGroup($value);

        /**
         * Raises <b>OnClick</b> event.
         * @param TEventParameter event parameter to be passed to the event handlers
         */
        public function onClick($param);

        /**
         * Raises <b>OnCommand</b> event.
         * @param TCommandEventParameter event parameter to be passed to the event handlers
         */
        public function onCommand($param);

        /**
         * @param boolean set by a panel to register this button as the default button for the panel.
         */
        public function setIsDefaultButton($value);

        /**
         * @return boolean true if this button is registered as a default button for a panel.
         */
        public function getIsDefaultButton();
}

/**
 * ISurroundable interface
 *
 * Identifies controls that may create an additional surrounding tag. The id of the
 * tag can be obtained with {@link getSurroundingTagID}.
 *
 * @package System.Web.UI
 * @since 3.1.2
 */
interface ISurroundable
{
        /**
         * @return string the id of the embedding tag of the control or the control's clientID if not surrounded
         */
        public function getSurroundingTagID();
}

/**
 * TBroadcastEventParameter class
 *
 * TBroadcastEventParameter encapsulates the parameter data for
 * events that are broadcasted. The name of of the event is specified via
 * {@link setName Name} property while the event parameter is via
 * {@link setParameter Parameter} property.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TBroadcastEventParameter extends TEventParameter
{
        private $_name;
        private $_param;

        /**
         * Constructor.
         * @param string name of the broadcast event
         * @param mixed parameter of the broadcast event
         */
        public function __construct($name='',$parameter=null)
        {
                $this->_name=$name;
                $this->_param=$parameter;
        }

        /**
         * @return string name of the broadcast event
         */
        public function getName()
        {
                return $this->_name;
        }

        /**
         * @param string name of the broadcast event
         */
        public function setName($value)
        {
                $this->_name=$value;
        }

        /**
         * @return mixed parameter of the broadcast event
         */
        public function getParameter()
        {
                return $this->_param;
        }

        /**
         * @param mixed parameter of the broadcast event
         */
        public function setParameter($value)
        {
                $this->_param=$value;
        }
}

/**
 * TCommandEventParameter class
 *
 * TCommandEventParameter encapsulates the parameter data for <b>Command</b>
 * event of button controls. You can access the name of the command via
 * {@link getCommandName CommandName} property, and the parameter carried
 * with the command via {@link getCommandParameter CommandParameter} property.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TCommandEventParameter extends TEventParameter
{
        private $_name;
        private $_param;

        /**
         * Constructor.
         * @param string name of the command
         * @param string parameter of the command
         */
        public function __construct($name='',$parameter='')
        {
                $this->_name=$name;
                $this->_param=$parameter;
        }

        /**
         * @return string name of the command
         */
        public function getCommandName()
        {
                return $this->_name;
        }

        /**
         * @return string parameter of the command
         */
        public function getCommandParameter()
        {
                return $this->_param;
        }
}


/**
 * TCompositeLiteral class
 *
 * TCompositeLiteral is used internally by {@link TTemplate} for representing
 * consecutive static strings, expressions and statements.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: TControl.php 2522 2008-10-13 21:40:53Z mikl $
 * @package System.Web.UI
 * @since 3.0
 */
class TCompositeLiteral extends TComponent implements IRenderable, IBindable
{
        const TYPE_EXPRESSION=0;
        const TYPE_STATEMENTS=1;
        const TYPE_DATABINDING=2;
        private $_container=null;
        private $_items=array();
        private $_expressions=array();
        private $_statements=array();
        private $_bindings=array();

        /**
         * Constructor.
         * @param array list of items to be represented by TCompositeLiteral
         */
        public function __construct($items)
        {
                $this->_items=array();
                $this->_expressions=array();
                $this->_statements=array();
                foreach($items as $id=>$item)
                {
                        if(is_array($item))
                        {
                                if($item[0]===self::TYPE_EXPRESSION)
                                        $this->_expressions[$id]=$item[1];
                                else if($item[0]===self::TYPE_STATEMENTS)
                                        $this->_statements[$id]=$item[1];
                                else if($item[0]===self::TYPE_DATABINDING)
                                        $this->_bindings[$id]=$item[1];
                                $this->_items[$id]='';
                        }
                        else
                                $this->_items[$id]=$item;
                }
        }

        /**
         * @return TComponent container of this component. It serves as the evaluation context of expressions and statements.
         */
        public function getContainer()
        {
                return $this->_container;
        }

        /**
         * @param TComponent container of this component. It serves as the evaluation context of expressions and statements.
         */
        public function setContainer(TComponent $value)
        {
                $this->_container=$value;
        }

        /**
         * Evaluates the expressions and/or statements in the component.
         */
        public function evaluateDynamicContent()
        {
                $context=$this->_container===null?$this:$this->_container;
                foreach($this->_expressions as $id=>$expression)
                        $this->_items[$id]=$context->evaluateExpression($expression);
                foreach($this->_statements as $id=>$statement)
                        $this->_items[$id]=$context->evaluateStatements($statement);
        }

        /**
         * Performs databindings.
         * This method is required by {@link IBindable}
         */
        public function dataBind()
        {
                $context=$this->_container===null?$this:$this->_container;
                foreach($this->_bindings as $id=>$binding)
                        $this->_items[$id]=$context->evaluateExpression($binding);
        }

        /**
         * Renders the content stored in this component.
         * This method is required by {@link IRenderable}
         * @param ITextWriter
         */
        public function render($writer)
        {
                $writer->write(implode('',$this->_items));
        }
}

?>