Widget Class
A base class for widgets, providing:
- The render lifecycle method, in addition to the init and destroy lifecycle methods provide by Base
- Abstract methods to support consistent MVC structure across widgets: renderer, renderUI, bindUI, syncUI
- Support for common widget attributes, such as boundingBox, contentBox, visible, disabled, focused, strings
Constructor
Widget
-
config
Parameters:
-
config
ObjectObject literal specifying widget configuration properties.
Item Index
Methods
- _addAttrs
- _addLazyAttr
- _addOutOfOrder
- _afterChildSelectedChange
- _aggregateAttrs
- _applyParsedConfig
- _applyParser
- _attrCfgHash
- _baseDestroy
- _baseInit
- _bindAttrUI
- _bindDOM
- _bindUI
- _bindUIChild
- _cloneDefaultValue
- _createUIEvent
- _defAttrChangeFn
- _defaultBB
- _defaultCB
- _defDestroyFn
- _defInitFn
- _defRenderFn
- _destroyBox
- _destroyHierarchy
- _destroyUIEvents
- _filterAdHocAttrs
- _filterUIEvent
- _fireAttrChange
- _getAttr
- _getAttrCfg
- _getAttrCfgs
- _getAttrInitVal
- _getAttrs
- _getClasses
- _getFullType
- _getHtmlParser
- _getInstanceAttrCfgs
- _getNodeToParse
- _getSrcNode
- _getStateVal
- _getType
- _getUIEventNode
- _getUIEventNode
- _guid
- _hasPotentialSubscribers
- _initAttrHost
- _initAttribute
- _initAttrs
- _initBase
- _initHierarchy
- _initHierarchyData
- _initUIEvent
- _isLazyAttr
- _isUIEvent
- _mapInstance
- _monitor
- _normAttrVals
- _onDocFocus
- _onDocMouseDown
- _parseType
- _preAddAttrs
- _preInitEventCfg
- _protectAttrs deprecated
- _publish
- _removeLoadingClassNames
- _renderBox
- _renderBoxClassNames
- _renderUI
- _set
- _setAttr
- _setAttrs
- _setAttrUI
- _setAttrVal
- _setBB
- _setBox
- _setCB
- _setStateVal
- _strSetter
- _syncAttrUI
- _syncUI
- _syncUIChild
- _uiSetChildSelected
- _uiSetDim
- _uiSetDisabled
- _uiSetFocused
- _uiSetHeight
- _uiSetTabIndex
- _uiSetVisible
- _uiSetWidth
- _uiSizeCB
- _unbindDOM
- _unbindUI
- _validTabIndex
- addAttr
- addAttrs
- addTarget
- after
- ancestor
- attrAdded
- before
- bindUI
- blur
- bubble
- destroy
- destructor
- detach
- detachAll
- disable
- enable
- fire
- focus
- get
- getAttrs
- getByNode static
- getClassName
- getClassName
- getEvent
- getSkinName
- getString deprecated
- getStrings deprecated
- getTargets
- hide
- init
- initializer
- isRoot
- modifyAttr
- next
- on
- once
- onceAfter
- parseType
- previous
- publish
- removeAttr
- removeTarget
- render
- renderer
- renderUI
- reset
- set
- setAttrs
- show
- subscribe deprecated
- syncUI
- toString
- unsubscribe deprecated
- unsubscribeAll deprecated
Properties
- _allowAdHocAttrs
- _buildCfg static
- _UI_ATTRS
- ATTRS static
- BOUNDING_TEMPLATE
- CONTENT_TEMPLATE
- CSS_PREFIX static
- DEF_PARENT_NODE
- DEF_UNIT
- HTML_PARSER static
- NAME static
- name deprecated
- UI_EVENTS
- UI_SRC static
Attributes
Events
Methods
_addAttrs
-
cfgs
-
values
-
lazy
Implementation behind the public addAttrs method.
This method is invoked directly by get if it encounters a scenario in which an attribute's valueFn attempts to obtain the value an attribute in the same group of attributes, which has not yet been added (on demand initialization).
Parameters:
-
cfgs
ObjectAn object with attribute name/configuration pairs.
-
values
ObjectAn object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.
-
lazy
BooleanWhether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.
_addLazyAttr
-
name
-
[lazyCfg]
Finishes initializing an attribute which has been lazily added.
_addOutOfOrder
-
name
-
cfg
Utility method used by get/set to add attributes encountered out of order when calling addAttrs().
For example, if:
this.addAttrs({
foo: {
setter: function() {
// make sure this bar is available when foo is added
this.get("bar");
}
},
bar: {
value: ...
}
});
_afterChildSelectedChange
-
event
Default attribute change listener for the selected
attribute, responsible for updating the UI, in response to
attribute changes.
Parameters:
-
event
EventFacadeThe event facade for the attribute change.
_aggregateAttrs
-
allAttrs
A helper method, used by _initHierarchyData to aggregate attribute configuration across the instances class hierarchy.
The method will protect the attribute configuration value to protect the statically defined default value in ATTRS if required (if the value is an object literal, array or the attribute configuration has cloneDefaultValue set to shallow or deep).
Parameters:
-
allAttrs
ArrayAn array of ATTRS definitions across classes in the hierarchy (subclass first, Base last)
Returns:
The aggregate set of ATTRS definitions for the instance
_applyParser
-
config
Utility method used to apply the HTML_PARSER
configuration for the
instance, to retrieve config data values.
Parameters:
-
config
ObjectUser configuration object (will be populated with values from Node)
_attrCfgHash
()
private
Utility method to define the attribute hash used to filter/whitelist property mixes for this class for iteration performance reasons.
_baseDestroy
()
private
Internal destroy implementation for BaseCore
_baseInit
()
private
Internal initialization implementation for BaseCore
_bindAttrUI
-
attrs
Binds after listeners for the list of attributes provided
Parameters:
-
attrs
Array
_bindDOM
()
protected
Sets up DOM listeners, on elements rendered by the widget.
_bindUI
()
protected
Sets up DOM and CustomEvent listeners for the widget.
_bindUIChild
()
protected
Binds event listeners responsible for updating the UI state in response to WidgetChild related state changes.
This method is invoked after bindUI is invoked for the Widget class using YUI's aop infrastructure.
_cloneDefaultValue
-
cfg
This method assumes that the value has already been checked to be an object. Since it's on a critical path, we don't want to re-do the check.
Parameters:
-
cfg
Object
_createUIEvent
-
type
Binds a delegated DOM event listener of the specified type to the Widget's outtermost DOM element to facilitate the firing of a Custom Event of the same type for the Widget instance.
Parameters:
-
type
StringString representing the name of the event
_defAttrChangeFn
-
e
-
eventFastPath
Default function for attribute change events.
Parameters:
-
e
EventFacadeThe event object for attribute change events.
-
eventFastPath
BooleanWhether or not we're using this as a fast path in the case of no listeners or not
_defaultBB
()
protected
Returns the default value for the boundingBox attribute.
For the Widget class, this will most commonly be null (resulting in a new boundingBox node instance being created), unless a srcNode was provided and CONTENT_TEMPLATE is null, in which case it will be srcNode. This behavior was introduced in @VERSION@ to accomodate single-box widgets whose BB & CB both point to srcNode (e.g. Y.Button).
_defaultCB
()
protected
Returns the default value for the contentBox attribute.
For the Widget class, this will be the srcNode if provided, otherwise null (resulting in a new contentBox node instance being created)
_defInitFn
-
e
Default init event handler
Parameters:
-
e
EventFacadeEvent object, with a cfg property which refers to the configuration object passed to the constructor.
_defRenderFn
-
e
-
parentNode
Default render handler
Parameters:
-
e
EventFacadeThe Event object
-
parentNode
NodeThe parent node to render to, if passed in to the
render
method
_destroyBox
()
protected
Removes and destroys the widgets rendered boundingBox, contentBox, and detaches bound UI events.
_destroyHierarchy
()
private
Destroys the class hierarchy for this instance by invoking the destructor method on the prototype of each class in the hierarchy.
_destroyUIEvents
()
private
Destructor logic for UI event infrastructure, invoked during Widget destruction.
_filterAdHocAttrs
-
allAttrs
-
userVals
Parameters:
-
allAttrs
ObjectThe set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.
-
userVals
ObjectThe config object passed in by the user, from which adhoc attrs are to be filtered.
Returns:
The set of adhoc attributes passed in, in the form of an object with attribute name/configuration pairs.
_filterUIEvent
-
evt
This method is used to determine if we should fire the UI Event or not. The default implementation makes sure that for nested delegates (nested unrelated widgets), we don't fire the UI event listener more than once at each level.
For example, without the additional filter, if you have nested widgets, each widget will have a delegate listener. If you click on the inner widget, the inner delegate listener's filter will match once, but the outer will match twice (based on delegate's design) - once for the inner widget, and once for the outer.
Parameters:
-
evt
DOMEventFacade
Returns:
true if it's OK to fire the custom UI event, false if not.
_fireAttrChange
-
attrName
-
subAttrName
-
currVal
-
newVal
-
opts
-
[cfg]
Utility method to help setup the event payload and fire the attribute change event.
Parameters:
-
attrName
StringThe name of the attribute
-
subAttrName
StringThe full path of the property being changed, if this is a sub-attribute value being change. Otherwise null.
-
currVal
AnyThe current value of the attribute
-
newVal
AnyThe new value of the attribute
-
opts
ObjectAny additional event data to mix into the attribute change event's event facade.
-
[cfg]
Object optionalThe attribute config stored in State, if already available.
_getAttr
-
name
Provides the common implementation for the public get method, allowing Attribute hosts to over-ride either method.
See get for argument details.
Parameters:
-
name
StringThe name of the attribute.
Returns:
The value of the attribute.
_getAttrCfg
-
name
Returns an object with the configuration properties (and value) for the given attribute. If attrName is not provided, returns the configuration properties for all attributes.
Parameters:
-
name
StringOptional. The attribute name. If not provided, the method will return the configuration for all attributes.
Returns:
The configuration properties for the given attribute, or all attributes.
_getAttrCfgs
()
Object
protected
Returns an aggregated set of attribute configurations, by traversing the class hierarchy.
Returns:
The hash of attribute configurations, aggregated across classes in the hierarchy This value is cached the first time the method, or _getClasses, is invoked. Subsequent invocations return the cached value.
_getAttrInitVal
-
attr
-
cfg
-
initValues
Returns the initial value of the given attribute from either the default configuration provided, or the over-ridden value if it exists in the set of initValues provided and the attribute is not read-only.
Parameters:
Returns:
The initial value of the attribute.
_getAttrs
-
attrs
Implementation behind the public getAttrs method, to get multiple attribute values.
Parameters:
Returns:
An object with attribute name/value pairs.
_getClasses
()
Function[]
protected
Returns the class hierarchy for this object, with BaseCore being the last class in the array.
Returns:
An array of classes (constructor functions), making up the class hierarchy for this object. This value is cached the first time the method, or _getAttrCfgs, is invoked. Subsequent invocations return the cached value.
_getFullType
-
type
Returns the fully qualified type, given a short type string. That is, returns "foo:bar" when given "bar" if "foo" is the configured prefix.
NOTE: This method, unlike _getType, does no checking of the value passed in, and is designed to be used with the low level _publish() method, for critical path implementations which need to fast-track publish for performance reasons.
Parameters:
-
type
StringThe short type to prefix
Returns:
The prefixed type, if a prefix is set, otherwise the type passed in
_getHtmlParser
()
Object
private
Gets the HTML_PARSER definition for this instance, by merging HTML_PARSER definitions across the class hierarchy.
Returns:
HTML_PARSER definition for this instance
_getInstanceAttrCfgs
-
allCfgs
A helper method used to isolate the attrs config for this instance to pass to addAttrs
,
from the static cached ATTRS for the class.
Parameters:
-
allCfgs
ObjectThe set of all attribute configurations for this instance. Attributes will be removed from this set, if they belong to the filtered class, so that by the time all classes are processed, allCfgs will be empty.
Returns:
The set of attributes to be added for this instance, suitable
for passing through to addAttrs
.
_getNodeToParse
()
Node
private
Determines whether we have a node reference which we should try and parse.
The current implementation does not parse nodes generated from CONTENT_TEMPLATE, only explicitly set srcNode, or contentBox attributes.
Returns:
The node reference to apply HTML_PARSER to.
_getStateVal
-
name
-
[cfg]
Gets the stored value for the attribute, from either the internal state object, or the state proxy if it exits
Parameters:
Returns:
The stored value of the attribute
_getType
()
private
If the instance has a prefix attribute and the event type is not prefixed, the instance prefix is applied to the supplied type.
_getUIEventNode
()
protected
Returns the node on which to bind delegate listeners.
_getUIEventNode
()
protected
Returns the node on which to bind delegate listeners.
Override of Widget's implementation of _getUIEventNode() to ensure that all event listeners are bound to the Widget's topmost DOM element. This ensures that the firing of each type of Widget UI event (click, mousedown, etc.) is facilitated by a single, top-level, delegated DOM event listener.
_guid
()
protected
_hasPotentialSubscribers
-
fullType
Parameters:
-
fullType
StringThe fully prefixed type name
Returns:
Whether the event has potential subscribers or not
_initAttrHost
-
attrs
-
values
-
lazy
Constructor logic for attributes. Initializes the host state, and sets up the inital attributes passed to the constructor.
Parameters:
-
attrs
ObjectThe attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
-
values
ObjectThe initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.
-
lazy
BooleanWhether or not to add attributes lazily (passed through to addAttrs).
_initAttribute
()
private
Initializes AttributeCore
_initAttrs
-
attrs
-
values
-
lazy
Utility method to set up initial attributes defined during construction, either through the constructor.ATTRS property, or explicitly passed in.
Parameters:
-
attrs
ObjectThe attributes to add during construction (passed through to addAttrs). These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
-
values
ObjectThe initial attribute values to apply (passed through to addAttrs). These are not merged/cloned. The caller is responsible for isolating user provided values if required.
-
lazy
BooleanWhether or not to add attributes lazily (passed through to addAttrs).
_initBase
-
config
Internal construction logic for BaseCore.
Parameters:
-
config
ObjectThe constructor configuration object
_initHierarchy
-
userVals
Initializes the class hierarchy for the instance, which includes initializing attributes for each class defined in the class's static ATTRS property and invoking the initializer method on the prototype of each class in the hierarchy.
Parameters:
-
userVals
ObjectObject with configuration property name/value pairs
_initHierarchyData
()
private
A helper method used by _getClasses and _getAttrCfgs, which determines both the array of classes and aggregate set of attribute configurations across the class hierarchy for the instance.
_initUIEvent
-
type
Sets up infrastructure required to fire a UI event.
Parameters:
-
type
StringString representing the name of the event
Returns:
_isLazyAttr
-
name
Checks whether or not the attribute is one which has been added lazily and still requires initialization.
Parameters:
-
name
StringThe name of the attribute
Returns:
true if it's a lazily added attribute, false otherwise.
_isUIEvent
-
type
Determines if the specified event is a UI event.
Parameters:
-
type
StringString representing the name of the event
Returns:
Event Returns the name of the UI Event, otherwise undefined.
_mapInstance
-
The
Utility method used to add an entry to the boundingBox id to instance map.
This method can be used to populate the instance with lazily created boundingBox Node references.
Parameters:
-
The
StringboundingBox id
_monitor
-
what
-
eventType
-
o
This is the entry point for the event monitoring system. You can monitor 'attach', 'detach', 'fire', and 'publish'. When configured, these events generate an event. click -> click_attach, click_detach, click_publish -- these can be subscribed to like other events to monitor the event system. Inividual published events can have monitoring turned on or off (publish can't be turned off before it it published) by setting the events 'monitor' config.
Parameters:
-
what
String'attach', 'detach', 'fire', or 'publish'
-
eventType
String | CustomEventThe prefixed name of the event being monitored, or the CustomEvent object.
-
o
ObjectInformation about the event interaction, such as fire() args, subscription category, publish config
_normAttrVals
-
valueHash
Utility method to normalize attribute values. The base implementation simply merges the hash to protect the original.
Parameters:
-
valueHash
ObjectAn object with attribute name/value pairs
Returns:
An object literal with 2 properties - "simple" and "complex", containing simple and complex attribute values respectively keyed by the top level attribute name, or null, if valueHash is falsey.
_onDocFocus
-
evt
DOM focus event handler, used to sync the state of the Widget with the DOM
Parameters:
-
evt
EventFacadeThe event facade for the DOM focus event
_onDocMouseDown
-
evt
"mousedown" event handler for the owner document of the widget's bounding box.
Parameters:
-
evt
EventFacadeThe event facade for the DOM focus event
_parseType
()
private
Returns an array with the detach key (if provided), and the prefixed event name from _getType Y.on('detachcategory| menu:click', fn)
_preAddAttrs
-
attrs
-
userVals
-
lazy
Implement the BaseCore _preAddAttrs method hook, to add
the srcNode and related attributes, so that HTML_PARSER
(which relies on this.get("srcNode")
) can merge in it's
results before the rest of the attributes are added.
_preInitEventCfg
-
config
Handles the special on, after and target properties which allow the user to easily configure on and after listeners as well as bubble targets during construction, prior to init.
Parameters:
-
config
ObjectThe user configuration object
_protectAttrs
-
attrs
Utility method to protect an attribute configuration hash, by merging the entire object and the individual attr config objects.
Parameters:
-
attrs
ObjectA hash of attribute to configuration object pairs.
Returns:
A protected version of the attrs argument.
_publish
-
fullType
-
etOpts
-
ceOpts
The low level event publish implementation. It expects all the massaging to have been done
outside of this method. e.g. the type
to fullType
conversion. It's designed to be a fast
path publish, which can be used by critical code paths to improve performance.
Parameters:
Returns:
The published event. If called without etOpts
or ceOpts
, this will
be the default CustomEvent
instance, and can be configured independently.
_removeLoadingClassNames
()
protected
Removes class names representative of the widget's loading state from the boundingBox.
_renderBox
-
parentNode
Helper method to collect the boundingBox and contentBox and append to the provided parentNode, if not already a child. The owner document of the boundingBox, or the owner document of the contentBox will be used as the document into which the Widget is rendered if a parentNode is node is not provided. If both the boundingBox and the contentBox are not currently in the document, and no parentNode is provided, the widget will be rendered to the current document's body.
Parameters:
-
parentNode
NodeThe parentNode to render the widget to. If not provided, and both the boundingBox and the contentBox are not currently in the document, the widget will be rendered to the current document's body.
_renderBoxClassNames
()
protected
Applies standard class names to the boundingBox and contentBox
_renderUI
()
protected
Initializes the UI state for the Widget's bounding/content boxes.
_set
-
name
-
val
-
[opts]
Allows setting of readOnly/writeOnce attributes. See set for argument details.
Parameters:
Returns:
A reference to the host object.
_setAttr
-
name
-
value
-
[opts]
-
force
Provides the common implementation for the public set and protected _set methods.
See set for argument details.
Parameters:
Returns:
A reference to the host object.
_setAttrs
-
attrs
-
[opts]
Implementation behind the public setAttrs method, to set multiple attribute values.
Parameters:
Returns:
A reference to the host object.
_setAttrVal
-
attrName
-
subAttrName
-
prevVal
-
newVal
-
[opts]
-
[attrCfg]
Updates the stored value of the attribute in the privately held State object, if validation and setter passes.
Parameters:
-
attrName
StringThe attribute name.
-
subAttrName
StringThe sub-attribute name, if setting a sub-attribute property ("x.y.z").
-
prevVal
AnyThe currently stored value of the attribute.
-
newVal
AnyThe value which is going to be stored.
-
[opts]
Object optionalOptional data providing the circumstances for the change.
-
[attrCfg]
Object optionalOptional config hash for the attribute. This is added for performance along the critical path, where the calling method has already obtained the config from state.
Returns:
true if the new attribute value was stored, false if not.
_setBB
-
node
Setter for the boundingBox attribute
Returns:
Node
_setBox
-
id
-
node
-
template
-
isBounding
Helper method to set the bounding/content box, or create it from the provided template if not found.
Parameters:
Returns:
The node
_setCB
-
node
Setter for the contentBox attribute
Returns:
Node
_setStateVal
-
name
-
value
Sets the stored value for the attribute, in either the internal state object, or the state proxy if it exits
Parameters:
-
name
StringThe name of the attribute
-
value
AnyThe value of the attribute
_strSetter
-
strings
The default setter for the strings attribute. Merges partial sets into the full string set, to allow users to partial sets of strings
Parameters:
-
strings
Object
Returns:
The full set of strings to set
_syncAttrUI
-
attrs
Invokes the _uiSet=ATTR NAME> method for the list of attributes provided
Parameters:
-
attrs
Array
_syncUI
()
protected
Updates the widget UI to reflect the attribute state.
_syncUIChild
()
protected
Synchronizes the UI to match the WidgetChild state.
This method is invoked after bindUI is invoked for the Widget class using YUI's aop infrastructure.
_uiSetChildSelected
-
selected
Updates the UI to reflect the selected
attribute value.
Parameters:
-
selected
NumberThe selected value to be reflected in the UI.
_uiSetDim
-
dim
-
val
_uiSetFocused
-
val
-
src
Sets the focused state for the UI
_uiSetHeight
-
val
Sets the height on the widget's bounding box element
_uiSetTabIndex
-
Number
Set the tabIndex on the widget's rendered UI
Parameters:
-
Number
Object
_uiSetWidth
-
val
Sets the width on the widget's bounding box element
_unbindDOM
()
protected
_unbindUI
()
protected
addAttr
-
name
-
config
-
lazy
Adds an attribute with the provided configuration to the host object.
The config argument object supports the following properties:
- value <Any>
- The initial value to set on the attribute
- valueFn <Function | String>
-
A function, which will return the initial value to set on the attribute. This is useful for cases where the attribute configuration is defined statically, but needs to reference the host instance ("this") to obtain an initial value. If both the value and valueFn properties are defined, the value returned by the valueFn has precedence over the value property, unless it returns undefined, in which case the value property is used.
valueFn can also be set to a string, representing the name of the instance method to be used to retrieve the value.
- readOnly <boolean>
- Whether or not the attribute is read only. Attributes having readOnly set to true cannot be modified by invoking the set method.
- writeOnce <boolean> or <string>
-
Whether or not the attribute is "write once". Attributes having writeOnce set to true,
can only have their values set once, be it through the default configuration,
constructor configuration arguments, or by invoking set.
The writeOnce attribute can also be set to the string "initOnly", in which case the attribute can only be set during initialization (when used with Base, this means it can only be set during construction)
- setter <Function | String>
-
The setter function used to massage or normalize the value passed to the set method for the attribute. The value returned by the setter will be the final stored value. Returning Attribute.INVALID_VALUE, from the setter will prevent the value from being stored.
setter can also be set to a string, representing the name of the instance method to be used as the setter function.
- getter <Function | String>
-
The getter function used to massage or normalize the value returned by the get method for the attribute. The value returned by the getter function is the value which will be returned to the user when they invoke get.
getter can also be set to a string, representing the name of the instance method to be used as the getter function.
- validator <Function | String>
-
The validator function invoked prior to setting the stored value. Returning false from the validator function will prevent the value from being stored.
validator can also be set to a string, representing the name of the instance method to be used as the validator function.
- lazyAdd <boolean>
- Whether or not to delay initialization of the attribute until the first call to get/set it. This flag can be used to over-ride lazy initialization on a per attribute basis, when adding multiple attributes through the addAttrs method.
The setter, getter and validator are invoked with the value and name passed in as the first and second arguments, and with the context ("this") set to the host object.
Configuration properties outside of the list mentioned above are considered private properties used internally by attribute, and are not intended for public use.
Parameters:
-
name
StringThe name of the attribute.
-
config
ObjectAn object with attribute configuration property/value pairs, specifying the configuration for the attribute.
NOTE: The configuration object is modified when adding an attribute, so if you need to protect the original values, you will need to merge the object.
-
lazy
Boolean(optional) Whether or not to add this attribute lazily (on the first call to get/set).
Returns:
A reference to the host object.
addAttrs
-
cfgs
-
values
-
lazy
Configures a group of attributes, and sets initial values.
NOTE: This method does not isolate the configuration object by merging/cloning. The caller is responsible for merging/cloning the configuration object if required.
Parameters:
-
cfgs
ObjectAn object with attribute name/configuration pairs.
-
values
ObjectAn object with attribute name/value pairs, defining the initial values to apply. Values defined in the cfgs argument will be over-written by values in this argument unless defined as read only.
-
lazy
BooleanWhether or not to delay the intialization of these attributes until the first call to get/set. Individual attributes can over-ride this behavior by defining a lazyAdd configuration property in their configuration. See addAttr.
Returns:
A reference to the host object.
addTarget
-
o
Registers another EventTarget as a bubble target. Bubble order is determined by the order registered. Multiple targets can be specified.
Events can only bubble if emitFacade is true.
Included in the event-custom-complex submodule.
Parameters:
-
o
EventTargetthe target to add
after
-
type
-
fn
-
[context]
-
[arg*]
Subscribe to a custom event hosted by this object. The supplied callback will execute after any listeners add via the subscribe method, and after the default function, if configured for the event, has executed.
Parameters:
Returns:
A subscription handle capable of detaching the subscription
ancestor
-
depth
Returns the Widget instance at the specified depth.
Parameters:
-
depth
NumberNumber representing the depth of the ancestor.
Returns:
Widget instance.
attrAdded
-
name
Checks if the given attribute has been added to the host
Parameters:
-
name
StringThe name of the attribute to check.
Returns:
true if an attribute with the given name has been added, false if it hasn't. This method will return true for lazily added attributes.
before
()
Executes the callback before a DOM event, custom event or method. If the first argument is a function, it is assumed the target is a method. For DOM and custom events, this is an alias for Y.on.
For DOM and custom events: type, callback, context, 0-n arguments
For methods: callback, object (method host), methodName, context, 0-n arguments
Returns:
detach handle
bindUI
()
protected
Configures/Sets up listeners to bind Widget State to UI/DOM
This method is not called by framework and is not chained automatically for the class hierarchy.
blur
()
chainable
Causes the Widget to lose focus by setting the "focused" attribute to "false"
bubble
-
evt
Propagate an event. Requires the event-custom-complex module.
Parameters:
-
evt
CustomEventthe custom event to propagate
Returns:
the aggregated return value from Event.Custom.fire
destroy
-
destroyAllNodes
Destroy lifecycle method. Fires the destroy event, prior to invoking destructors for the class hierarchy. Overrides Base's implementation, to support arguments to destroy
Subscribers to the destroy event can invoke preventDefault on the event object, to prevent destruction from proceeding.
Parameters:
-
destroyAllNodes
BooleanIf true, all nodes contained within the Widget are removed and destroyed. Defaults to false due to potentially high run-time cost.
Returns:
A reference to this object
destructor
()
protected
Destructor lifecycle implementation for the Widget class. Purges events attached to the bounding box and content box, removes them from the DOM and removes the Widget from the list of registered widgets.
detach
-
type
-
fn
-
context
Detach one or more listeners the from the specified event
Parameters:
-
type
String | ObjectEither the handle to the subscriber or the type of event. If the type is not specified, it will attempt to remove the listener from all hosted events.
-
fn
FunctionThe subscribed function to unsubscribe, if not supplied, all subscribers will be removed.
-
context
ObjectThe custom object passed to subscribe. This is optional, but if supplied will be used to disambiguate multiple listeners that are the same (e.g., you subscribe many object using a function that lives on the prototype)
Returns:
the host
detachAll
-
type
Removes all listeners from the specified event. If the event type is not specified, all listeners from all hosted custom events will be removed.
Parameters:
-
type
StringThe type, or name of the event
disable
()
chainable
Set the Widget's "disabled" attribute to "true".
enable
()
chainable
Set the Widget's "disabled" attribute to "false".
fire
-
type
-
arguments
Fire a custom event by name. The callback functions will be executed from the context specified when the event was created, and with the following parameters.
The first argument is the event type, and any additional arguments are passed to the listeners as parameters. If the first of these is an object literal, and the event is configured to emit an event facade, that object is mixed into the event facade and the facade is provided in place of the original object.
If the custom event object hasn't been created, then the event hasn't been published and it has no subscribers. For performance sake, we immediate exit in this case. This means the event won't bubble, so if the intention is that a bubble target be notified, the event must be published on this object first.
Parameters:
-
type
String | ObjectThe type of the event, or an object that contains a 'type' property.
-
arguments
Object*an arbitrary set of parameters to pass to the handler. If the first of these is an object literal and the event is configured to emit an event facade, the event facade will replace that parameter after the properties the object literal contains are copied to the event facade.
Returns:
True if the whole lifecycle of the event went through, false if at any point the event propagation was halted.
focus
()
chainable
Causes the Widget to receive the focus by setting the "focused" attribute to "true".
get
-
name
Returns the current value of the attribute. If the attribute has been configured with a 'getter' function, this method will delegate to the 'getter' to obtain the value of the attribute.
Parameters:
-
name
StringThe name of the attribute. If the value of the attribute is an Object, dot notation can be used to obtain the value of a property of the object (e.g.
get("x.y.z")
)
Returns:
The value of the attribute
getAttrs
-
attrs
Gets multiple attribute values.
Parameters:
Returns:
An object with attribute name/value pairs.
getByNode
-
node
Returns the widget instance whose bounding box contains, or is, the given node.
In the case of nested widgets, the nearest bounding box ancestor is used to return the widget instance.
Parameters:
Returns:
Widget instance, or null if not found.
getClassName
-
args
Generate a standard prefixed classname for the Widget, prefixed by the default prefix defined
by the Y.config.classNamePrefix
attribute used by ClassNameManager
and
Widget.NAME.toLowerCase()
(e.g. "yui-widget-xxxxx-yyyyy", based on default values for
the prefix and widget class name).
The instance based version of this method can be used to generate standard prefixed classnames, based on the instances NAME, as opposed to Widget.NAME. This method should be used when you need to use a constant class name across different types instances.
Parameters:
-
args
String* multiple0..n strings which should be concatenated, using the default separator defined by ClassNameManager, to create the class name
getClassName
-
[classnames*]
Returns a class name prefixed with the the value of the
YUI.config.classNamePrefix
attribute + the instances NAME
property.
Uses YUI.config.classNameDelimiter
attribute to delimit the provided strings.
e.g.
// returns "yui-slider-foo-bar", for a slider instance var scn = slider.getClassName('foo','bar');// returns "yui-overlay-foo-bar", for an overlay instance var ocn = overlay.getClassName('foo','bar');
Parameters:
-
[classnames*]
String optionalOne or more classname bits to be joined and prefixed
getEvent
-
type
-
prefixed
Returns the custom event of the provided type has been created, a falsy value otherwise
Parameters:
Returns:
the custom event or null
getSkinName
-
[skinPrefix]
Returns the name of the skin that's currently applied to the widget.
Searches up the Widget's ancestor axis for, by default, a class yui3-skin-(name), and returns the (name) portion. Otherwise, returns null.
This is only really useful after the widget's DOM structure is in the document, either by render or by progressive enhancement.
Parameters:
-
[skinPrefix]
String optionalThe prefix which the implementation uses for the skin ("yui3-skin-" is the default).
NOTE: skinPrefix will be used as part of a regular expression:
new RegExp('\b' + skinPrefix + '(\S+)')
Although an unlikely use case, literal characters which may result in an invalid regular expression should be escaped.
Returns:
The name of the skin, or null, if a matching skin class is not found.
getString
-
key
Helper method to get a specific string value
Parameters:
-
key
String
Returns:
The string
getStrings
-
key
Helper method to get the complete set of strings for the widget
Parameters:
-
key
String
Returns:
The strings
getTargets
()
Returns an array of bubble targets for this object.
Returns:
EventTarget[]
hide
()
chainable
Hides the Widget by setting the "visible" attribute to "false".
init
-
cfg
Init lifecycle method, invoked during construction. Sets up attributes and invokes initializers for the class hierarchy.
Parameters:
-
cfg
ObjectObject with configuration property name/value pairs
Returns:
A reference to this object
initializer
-
config
Initializer lifecycle implementation for the Widget class. Registers the widget instance, and runs through the Widget's HTML_PARSER definition.
Parameters:
-
config
ObjectConfiguration object literal for the widget
isRoot
()
Boolean
Determines if the Widget is the root Widget in the object hierarchy.
Returns:
Boolean indicating if Widget is the root Widget in the object hierarchy.
modifyAttr
-
name
-
config
Updates the configuration of an attribute which has already been added.
The properties which can be modified through this interface are limited to the following subset of attributes, which can be safely modified after a value has already been set on the attribute:
- readOnly;
- writeOnce;
- broadcast; and
- getter.
Note: New attributes cannot be added using this interface. New attributes must be added using addAttr, or an appropriate manner for a class which utilises Attributes (e.g. the ATTRS property in Base).
next
-
circular
Returns the Widget's next sibling.
Parameters:
-
circular
BooleanBoolean indicating if the parent's first child should be returned if the child has no next sibling.
Returns:
Widget instance.
on
-
type
-
fn
-
[context]
-
[arg*]
Subscribe a callback function to a custom event fired by this object or from an object that bubbles its events to this object.
this.on("change", this._onChange, this);
Callback functions for events published with emitFacade = true
will
receive an EventFacade
as the first argument (typically named "e").
These callbacks can then call e.preventDefault()
to disable the
behavior published to that event's defaultFn
. See the EventFacade
API for all available properties and methods. Subscribers to
non-emitFacade
events will receive the arguments passed to fire()
after the event name.
To subscribe to multiple events at once, pass an object as the first argument, where the key:value pairs correspond to the eventName:callback.
this.on({
"attrChange" : this._onAttrChange,
"change" : this._onChange
});
You can also pass an array of event names as the first argument to subscribe to all listed events with the same callback.
this.on([ "change", "attrChange" ], this._onChange);
Returning false
from a callback is supported as an alternative to
calling e.preventDefault(); e.stopPropagation();
. However, it is
recommended to use the event methods whenever possible.
Parameters:
Returns:
A subscription handle capable of detaching that subscription
once
-
type
-
fn
-
[context]
-
[arg*]
Listen to a custom event hosted by this object one time.
This is the equivalent to on
except the
listener is immediatelly detached when it is executed.
Parameters:
Returns:
A subscription handle capable of detaching the subscription
onceAfter
-
type
-
fn
-
[context]
-
[arg*]
Listen to a custom event hosted by this object one time.
This is the equivalent to after
except the
listener is immediatelly detached when it is executed.
Parameters:
Returns:
A subscription handle capable of detaching that subscription
parseType
-
type
-
[pre]
Takes the type parameter passed to 'on' and parses out the various pieces that could be included in the type. If the event type is passed without a prefix, it will be expanded to include the prefix one is supplied or the event target is configured with a default prefix.
Parameters:
Returns:
an array containing:
- the detach category, if supplied,
- the prefixed event type,
- whether or not this is an after listener,
- the supplied event type
previous
-
circular
Returns the Widget's previous sibling.
Parameters:
-
circular
BooleanBoolean indicating if the parent's last child should be returned if the child has no previous sibling.
Returns:
Widget instance.
publish
-
type
-
opts
Creates a new custom event of the specified type. If a custom event by that name already exists, it will not be re-created. In either case the custom event is returned.
Parameters:
-
type
Stringthe type, or name of the event
-
opts
Objectoptional config params. Valid properties are:
-
[broadcast=false]
Boolean optionalwhether or not the YUI instance and YUI global are notified when the event is fired.
-
[bubbles=true]
Boolean optionalWhether or not this event bubbles. Events can only bubble if
emitFacade
is true. -
[context=this]
Object optionalthe default execution context for the listeners.
-
[defaultFn]
Function optionalthe default function to execute when this event fires if preventDefault was not called.
-
[emitFacade=false]
Boolean optionalwhether or not this event emits a facade.
-
[prefix]
String optionalthe prefix for this targets events, e.g., 'menu' in 'menu:click'.
-
[fireOnce=false]
Boolean optionalif an event is configured to fire once, new subscribers after the fire will be notified immediately.
-
[async=false]
Boolean optionalfireOnce event listeners will fire synchronously if the event has already fired unless
async
istrue
. -
[preventable=true]
Boolean optionalwhether or not
preventDefault()
has an effect. -
[preventedFn]
Function optionala function that is executed when
preventDefault()
is called. -
[queuable=false]
Boolean optionalwhether or not this event can be queued during bubbling.
-
[silent]
Boolean optionalif silent is true, debug messages are not provided for this event.
-
[stoppedFn]
Function optionala function that is executed when stopPropagation is called.
-
[monitored]
Boolean optionalspecifies whether or not this event should send notifications about when the event has been attached, detached, or published.
-
[type]
String optionalthe event type (valid option if not provided as the first parameter to publish).
-
Returns:
the custom event
removeAttr
-
name
Removes an attribute from the host object
Parameters:
-
name
StringThe name of the attribute to be removed.
render
-
parentNode
Establishes the initial DOM for the widget. Invoking this method will lead to the creating of all DOM elements for the widget (or the manipulation of existing DOM elements for the progressive enhancement use case).
This method should only be invoked once for an initialized widget.
It delegates to the widget specific renderer method to do the actual work.
Parameters:
-
parentNode
Object | StringOptional. The Node under which the Widget is to be rendered. This can be a Node instance or a CSS selector string.
If the selector string returns more than one Node, the first node will be used as the parentNode. NOTE: This argument is required if both the boundingBox and contentBox are not currently in the document. If it's not provided, the Widget will be rendered to the body of the current document in this case.
renderer
()
protected
Creates DOM (or manipulates DOM for progressive enhancement) This method is invoked by render() and is not chained automatically for the class hierarchy (unlike initializer, destructor) so it should be chained manually for subclasses if required.
renderUI
()
protected
Adds nodes to the DOM
This method is not called by framework and is not chained automatically for the class hierarchy.
reset
-
name
Resets the attribute (or all attributes) to its initial value, as long as the attribute is not readOnly, or writeOnce.
Parameters:
-
name
StringOptional. The name of the attribute to reset. If omitted, all attributes are reset.
Returns:
A reference to the host object.
set
-
name
-
value
-
[opts]
Sets the value of an attribute.
Parameters:
-
name
StringThe name of the attribute. If the current value of the attribute is an Object, dot notation can be used to set the value of a property within the object (e.g.
set("x.y.z", 5)
). -
value
AnyThe value to set the attribute to.
-
[opts]
Object optionalOptional data providing the circumstances for the change.
Returns:
A reference to the host object.
setAttrs
-
attrs
-
[opts]
Sets multiple attribute values.
Parameters:
Returns:
A reference to the host object.
show
()
chainable
Shows the Widget by setting the "visible" attribute to "true".
subscribe
()
deprecated
subscribe to an event
syncUI
()
protected
Refreshes the rendered UI, based on Widget State
This method is not called by framework and is not chained automatically for the class hierarchy.
toString
()
String
Generic toString implementation for all widgets.
Returns:
The default string value for the widget [ displays the NAME of the instance, and the unique id ]
unsubscribe
()
deprecated
detach a listener
unsubscribeAll
-
type
Removes all listeners from the specified event. If the event type is not specified, all listeners from all hosted custom events will be removed.
Parameters:
-
type
StringThe type, or name of the event
Properties
_allowAdHocAttrs
Boolean
protected
This property controls whether or not instances of this class should allow users to add ad-hoc attributes through the constructor configuration hash.
AdHoc attributes are attributes which are not defined by the class, and are not handled by the MyClass._NON_ATTRS_CFG
Default: undefined (false)
_buildCfg
Object
private
final
static
The build configuration for the Widget class.
Defines the static fields which need to be aggregated, when this class is used as the main class passed to the Base.build method.
_UI_ATTRS
Object
private
The lists of UI attributes to bind and sync for widget's _bindUI and _syncUI implementations
ATTRS
Object
static
Static property used to define the default attribute configuration for the Widget.
CONTENT_TEMPLATE
String
Property defining the markup template for content box. If your Widget doesn't need the dual boundingBox/contentBox structure, set CONTENT_TEMPLATE to null, and contentBox and boundingBox will both point to the same Node.
CSS_PREFIX
String
private
static
The css prefix which the static Widget.getClassName method should use when constructing class names
Default: Widget.NAME.toLowerCase()
DEF_PARENT_NODE
String | Node
Default node to render the bounding box to. If not set, will default to the current document body.
HTML_PARSER
Object
static
Object hash, defining how attribute values are to be parsed from markup contained in the widget's content box. e.g.:
{ // Set single Node references using selector syntax // (selector is run through node.one) titleNode: "span.yui-title", // Set NodeList references using selector syntax // (array indicates selector is to be run through node.all) listNodes: ["li.yui-item"], // Set other attribute types, using a parse function. // Context is set to the widget instance. label: function(contentBox) { return contentBox.one("span.title").get("innerHTML"); } }
NAME
String
static
Static property provides a string to identify the class.
Currently used to apply class identifiers to the bounding box and to classify events fired by the widget.
UI_SRC
String
final
static
Constant used to identify state changes originating from the DOM (as opposed to the JavaScript model).
Attributes
boundingBox
String | Node
The outermost DOM node for the Widget, used for sizing and positioning of a Widget as well as a containing element for any decorator elements used for skinning.
Fires event boundingBoxChange
Fires when the value for the configuration attribute boundingBox
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
contentBox
String | Node
A DOM node that is a direct descendant of a Widget's bounding box that houses its content.
Fires event contentBoxChange
Fires when the value for the configuration attribute contentBox
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
destroyed
Boolean
readonly
Flag indicating whether or not this object has been through the destroy lifecycle phase.
Default: false
Fires event destroyedChange
Fires when the value for the configuration attribute destroyed
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
disabled
Boolean
Boolean indicating if the Widget should be disabled. The disabled implementation is left to the specific classes extending widget.
Default: false
Fires event disabledChange
Fires when the value for the configuration attribute disabled
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
focused
Boolean
readonly
Boolean indicating if the Widget, or one of its descendants, has focus.
Default: false
Fires event focusedChange
Fires when the value for the configuration attribute focused
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
height
String | Number
String with units, or number, representing the height of the Widget. If a number is provided, the default unit, defined by the Widgets DEF_UNIT, property is used.
Default: EMPTY_STR
Fires event heightChange
Fires when the value for the configuration attribute height
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
id
String
Default: Generated using guid()
Fires event idChange
Fires when the value for the configuration attribute id
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
initialized
Boolean
readonly
Flag indicating whether or not this object has been through the init lifecycle phase.
Default: false
Fires event initializedChange
Fires when the value for the configuration attribute initialized
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
render
Boolean | Node
Whether or not to render the widget automatically after init, and optionally, to which parent node.
Fires event renderChange
Fires when the value for the configuration attribute render
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
rendered
Boolean
readonly
Flag indicating whether or not this Widget has been through the render lifecycle phase.
Default: false
Fires event renderedChange
Fires when the value for the configuration attribute rendered
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
srcNode
String | Node
The DOM node to parse for configuration values, passed to the Widget's HTML_PARSER definition
Fires event srcNodeChange
Fires when the value for the configuration attribute srcNode
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
strings
Object
Collection of strings used to label elements of the Widget's UI.
Default: null
Fires event stringsChange
Fires when the value for the configuration attribute strings
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
tabIndex
Number
Number (between -32767 to 32767) indicating the widget's position in the default tab flow. The value is used to set the "tabIndex" attribute on the widget's bounding box. Negative values allow the widget to receive DOM focus programmatically (by calling the focus method), while being removed from the default tab flow. A value of null removes the "tabIndex" attribute from the widget's bounding box.
Default: null
Fires event tabIndexChange
Fires when the value for the configuration attribute tabIndex
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
visible
Boolean
Boolean indicating whether or not the Widget is visible.
Default: TRUE
Fires event visibleChange
Fires when the value for the configuration attribute visible
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
width
String | Number
String with units, or number, representing the width of the Widget. If a number is provided, the default unit, defined by the Widgets DEF_UNIT, property is used.
Default: EMPTY_STR
Fires event widthChange
Fires when the value for the configuration attribute width
is
changed. You can listen for the event using the on
method if you
wish to be notified before the attribute's value has changed, or
using the after
method if you wish to be notified after the
attribute's value has changed.
Parameters:
-
e
EventFacadeAn Event Facade object with the following attribute-specific properties added:
Events
destroy
Lifecycle event for the destroy phase, fired prior to destruction. Invoking the preventDefault method on the event object provided to subscribers will prevent destruction from proceeding.
Subscribers to the "after" moment of this event, will be notified after destruction is complete (and as a result cannot prevent destruction).
Event Payload:
-
e
EventFacadeEvent object
init
Lifecycle event for the init phase, fired prior to initialization. Invoking the preventDefault() method on the event object provided to subscribers will prevent initialization from occuring.
Subscribers to the "after" momemt of this event, will be notified after initialization of the object is complete (and therefore cannot prevent initialization).
Event Payload:
-
e
EventFacadeEvent object, with a cfg property which refers to the configuration object passed to the constructor.
render
Lifecycle event for the render phase, fired prior to rendering the UI for the widget (prior to invoking the widget's renderer method).
Subscribers to the "on" moment of this event, will be notified before the widget is rendered.
Subscribers to the "after" moment of this event, will be notified after rendering is complete.
Event Payload:
-
e
EventFacadeThe Event Facade
widget:contentUpdate
Notification event, which widget implementations can fire, when they change the content of the widget. This event has no default behavior and cannot be prevented, so the "on" or "after" moments are effectively equivalent (with on listeners being invoked before after listeners).
Event Payload:
-
e
EventFacadeThe Event Facade