File yui3/src/attribute/js/AttributeObservable.js
/*For log lines*/
/*jshint maxlen:200*/
/**
* The attribute module provides an augmentable Attribute implementation, which
* adds configurable attributes and attribute change events to the class being
* augmented. It also provides a State class, which is used internally by Attribute,
* but can also be used independently to provide a name/property/value data structure to
* store state.
*
* @module attribute
*/
/**
* The `attribute-observable` submodule provides augmentable attribute change event support
* for AttributeCore based implementations.
*
* @module attribute
* @submodule attribute-observable
*/
var EventTarget = Y.EventTarget,
CHANGE = "Change",
BROADCAST = "broadcast";
/**
* Provides an augmentable implementation of attribute change events for
* AttributeCore.
*
* @class AttributeObservable
* @extensionfor AttributeCore
* @uses EventTarget
*/
function AttributeObservable() {
// Perf tweak - avoid creating event literals if not required.
this._ATTR_E_FACADE = {};
EventTarget.call(this, {emitFacade:true});
}
AttributeObservable._ATTR_CFG = [BROADCAST];
AttributeObservable.prototype = {
/**
* Sets the value of an attribute.
*
* @method set
* @chainable
*
* @param {String} name The 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. <code>set("x.y.z", 5)</code>).
*
* @param {Any} value The value to set the attribute to.
*
* @param {Object} opts (Optional) Optional event data to be mixed into
* the event facade passed to subscribers of the attribute's change event. This
* can be used as a flexible way to identify the source of a call to set, allowing
* the developer to distinguish between set called internally by the host, vs.
* set called externally by the application developer.
*
* @return {Object} A reference to the host object.
*/
set : function(name, val, opts) {
return this._setAttr(name, val, opts);
},
/**
* Allows setting of readOnly/writeOnce attributes. See <a href="#method_set">set</a> for argument details.
*
* @method _set
* @protected
* @chainable
*
* @param {String} name The name of the attribute.
* @param {Any} val The value to set the attribute to.
* @param {Object} opts (Optional) Optional event data to be mixed into
* the event facade passed to subscribers of the attribute's change event.
* @return {Object} A reference to the host object.
*/
_set : function(name, val, opts) {
return this._setAttr(name, val, opts, true);
},
/**
* Sets multiple attribute values.
*
* @method setAttrs
* @param {Object} attrs An object with attributes name/value pairs.
* @param {Object} opts Properties to mix into the event payload. These are shared and mixed into each set
* @return {Object} A reference to the host object.
* @chainable
*/
setAttrs : function(attrs, opts) {
return this._setAttrs(attrs, opts);
},
/**
* Implementation behind the public setAttrs method, to set multiple attribute values.
*
* @method _setAttrs
* @protected
* @param {Object} attrs An object with attributes name/value pairs.
* @param {Object} opts Properties to mix into the event payload. These are shared and mixed into each set
* @return {Object} A reference to the host object.
* @chainable
*/
_setAttrs : function(attrs, opts) {
var attr;
for (attr in attrs) {
if ( attrs.hasOwnProperty(attr) ) {
this.set(attr, attrs[attr], opts);
}
}
return this;
},
/**
* Utility method to help setup the event payload and fire the attribute change event.
*
* @method _fireAttrChange
* @private
* @param {String} attrName The name of the attribute
* @param {String} subAttrName The full path of the property being changed,
* if this is a sub-attribute value being change. Otherwise null.
* @param {Any} currVal The current value of the attribute
* @param {Any} newVal The new value of the attribute
* @param {Object} opts Any additional event data to mix into the attribute change event's event facade.
* @param {Object} [cfg] The attribute config stored in State, if already available.
*/
_fireAttrChange : function(attrName, subAttrName, currVal, newVal, opts, cfg) {
var host = this,
eventName = this._getFullType(attrName + CHANGE),
state = host._state,
facade,
broadcast,
e;
if (!cfg) {
cfg = state.data[attrName] || {};
}
if (!cfg.published) {
// PERF: Using lower level _publish() for
// critical path performance
e = host._publish(eventName);
e.emitFacade = true;
e.defaultTargetOnly = true;
e.defaultFn = host._defAttrChangeFn;
broadcast = cfg.broadcast;
if (broadcast !== undefined) {
e.broadcast = broadcast;
}
cfg.published = true;
}
if (opts) {
facade = Y.merge(opts);
facade._attrOpts = opts;
} else {
facade = host._ATTR_E_FACADE;
}
// Not using the single object signature for fire({type:..., newVal:...}), since
// we don't want to override type. Changed to the fire(type, {newVal:...}) signature.
facade.attrName = attrName;
facade.subAttrName = subAttrName;
facade.prevVal = currVal;
facade.newVal = newVal;
if (host._hasPotentialSubscribers(eventName)) {
host.fire(eventName, facade);
} else {
this._setAttrVal(attrName, subAttrName, currVal, newVal, opts, cfg);
}
},
/**
* Default function for attribute change events.
*
* @private
* @method _defAttrChangeFn
* @param {EventFacade} e The event object for attribute change events.
* @param {boolean} eventFastPath Whether or not we're using this as a fast path in the case of no listeners or not
*/
_defAttrChangeFn : function(e, eventFastPath) {
var opts = e._attrOpts;
if (opts) {
delete e._attrOpts;
}
if (!this._setAttrVal(e.attrName, e.subAttrName, e.prevVal, e.newVal, opts)) {
Y.log('State not updated and stopImmediatePropagation called for attribute: ' + e.attrName + ' , value:' + e.newVal, 'warn', 'attribute');
if (!eventFastPath) {
// Prevent "after" listeners from being invoked since nothing changed.
e.stopImmediatePropagation();
}
} else {
if (!eventFastPath) {
e.newVal = this.get(e.attrName);
}
}
}
};
// Basic prototype augment - no lazy constructor invocation.
Y.mix(AttributeObservable, EventTarget, false, null, 1);
Y.AttributeObservable = AttributeObservable;
/**
The `AttributeEvents` class extension was deprecated in YUI 3.8.0 and is now
an alias for the `AttributeObservable` class extension. Use that class
extnesion instead. This alias will be removed in a future version of YUI.
@class AttributeEvents
@uses EventTarget
@deprecated Use `AttributeObservable` instead.
@see AttributeObservable
**/
Y.AttributeEvents = AttributeObservable;