attribute-base.js revision 3250d374362f1262404330f9e1ff12ef90fd9ecc
YUI.add('attribute-base', function(Y) {
/**
* The State class maintains state for a collection of named items, with
* a varying number of properties defined.
*
* It avoids the need to create a separate class for the item, and separate instances
* of these classes for each item, by storing the state in a 2 level hash table,
* improving performance when the number of items is likely to be large.
*
* @constructor
* @class State
*/
Y.State = function() {
/**
* Hash of attributes
* @property data
*/
this.data = {};
};
Y.State.prototype = {
/**
* Adds a property to an item.
*
* @method add
* @param name {String} The name of the item.
* @param key {String} The name of the property.
* @param val {Any} The value of the property.
*/
add : function(name, key, val) {
var d = this.data;
d[key] = d[key] || {};
d[key][name] = val;
},
/**
* Adds multiple properties to an item.
*
* @method addAll
* @param name {String} The name of the item.
* @param o {Object} A hash of property/value pairs.
*/
addAll: function(name, o) {
var key;
for (key in o) {
if (o.hasOwnProperty(key)) {
this.add(name, key, o[key]);
}
}
},
/**
* Removes a property from an item.
*
* @method remove
* @param name {String} The name of the item.
* @param key {String} The property to remove.
*/
remove: function(name, key) {
var d = this.data;
if (d[key] && (name in d[key])) {
delete d[key][name];
}
},
/**
* Removes multiple properties from an item, or remove the item completely.
*
* @method removeAll
* @param name {String} The name of the item.
* @param o {Object|Array} Collection of properties to delete. If not provided, the entire item is removed.
*/
removeAll: function(name, o) {
var d = this.data;
Y.each(o || d, function(v, k) {
if(Y.Lang.isString(k)) {
this.remove(name, k);
} else {
this.remove(name, v);
}
}, this);
},
/**
* For a given item, returns the value of the property requested, or undefined if not found.
*
* @method get
* @param name {String} The name of the item
* @param key {String} Optional. The property value to retrieve.
* @return {Any} The value of the supplied property.
*/
get: function(name, key) {
var d = this.data;
return (d[key] && name in d[key]) ? d[key][name] : undefined;
},
/**
* For the given item, returns a disposable object with all of the
* item's property/value pairs.
*
* @method getAll
* @param name {String} The name of the item
* @return {Object} An object with property/value pairs for the item.
*/
getAll : function(name) {
var d = this.data, o;
Y.each(d, function(v, k) {
if (name in d[k]) {
o = o || {};
o[k] = v[name];
}
}, this);
return o;
}
};
/**
* 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-base submodule provides core attribute handling support, with everything
* aside from complex attribute handling in the provider's constructor.
*
* @module attribute
* @submodule attribute-base
*/
var O = Y.Object,
Lang = Y.Lang,
EventTarget = Y.EventTarget,
DOT = ".",
CHANGE = "Change",
// Externally configurable props
GETTER = "getter",
SETTER = "setter",
READ_ONLY = "readOnly",
WRITE_ONCE = "writeOnce",
VALIDATOR = "validator",
VALUE = "value",
VALUE_FN = "valueFn",
BROADCAST = "broadcast",
LAZY_ADD = "lazyAdd",
BYPASS_PROXY = "_bypassProxy",
FN_REFS = [SETTER, GETTER, VALIDATOR, VALUE_FN],
// Used for internal state management
ADDED = "added",
INITIALIZING = "initializing",
INIT_VALUE = "initValue",
PUBLISHED = "published",
DEF_VALUE = "defaultValue",
LAZY = "lazy",
IS_LAZY_ADD = "isLazyAdd",
INVALID_VALUE,
MODIFIABLE = {};
// Properties which can be changed after the attribute has been added.
MODIFIABLE[READ_ONLY] = 1;
MODIFIABLE[WRITE_ONCE] = 1;
MODIFIABLE[GETTER] = 1;
MODIFIABLE[BROADCAST] = 1;
/**
* <p>
* Attribute provides configurable attribute support along with attribute change events. It is designed to be
* augmented on to a host class, and provides the host with the ability to configure attributes to store and retrieve state,
* along with attribute change events.
* </p>
* <p>For example, attributes added to the host can be configured:</p>
* <ul>
* <li>As read only.</li>
* <li>As write once.</li>
* <li>With a setter function, which can be used to manipulate
* values passed to Attribute's <a href="#method_set">set</a> method, before they are stored.</li>
* <li>With a getter function, which can be used to manipulate stored values,
* before they are returned by Attribute's <a href="#method_get">get</a> method.</li>
* <li>With a validator function, to validate values before they are stored.</li>
* </ul>
*
* <p>See the <a href="#method_addAttr">addAttr</a> method, for the complete set of configuration
* options available for attributes</p>.
*
* <p><strong>NOTE:</strong> Most implementations will be better off extending the <a href="Base.html">Base</a> class,
* instead of augmenting Attribute directly. Base augments Attribute and will handle the initial configuration
* of attributes for derived classes, accounting for values passed into the constructor.</p>
*
* @class Attribute
* @uses EventTarget
*/
function Attribute() {
var host = this, // help compression
attrs = this.constructor.ATTRS,
Base = Y.Base;
// Perf tweak - avoid creating event literals if not required.
host._ATTR_E_FACADE = {};
EventTarget.call(host, {emitFacade:true});
// _conf maintained for backwards compat
host._conf = host._state = new Y.State();
host._stateProxy = host._stateProxy || null;
host._requireAddAttr = host._requireAddAttr || false;
// ATTRS support for Node, which is not Base based
if ( attrs && !(Base && host instanceof Base)) {
host.addAttrs(this._protectAttrs(attrs));
}
}
/**
* <p>The value to return from an attribute setter in order to prevent the set from going through.</p>
*
* <p>You can return this value from your setter if you wish to combine validator and setter
* functionality into a single setter function, which either returns the massaged value to be stored or
* Attribute.INVALID_VALUE to prevent invalid values from being stored.</p>
*
* @property Attribute.INVALID_VALUE
* @type Object
* @static
* @final
*/
Attribute.INVALID_VALUE = {};
INVALID_VALUE = Attribute.INVALID_VALUE;
/**
* The list of properties which can be configured for
* each attribute (e.g. setter, getter, writeOnce etc.).
*
* This property is used internally as a whitelist for faster
* Y.mix operations.
*
* @property Attribute._ATTR_CFG
* @type Array
* @static
* @protected
*/
Attribute._ATTR_CFG = [SETTER, GETTER, VALIDATOR, VALUE, VALUE_FN, WRITE_ONCE, READ_ONLY, LAZY_ADD, BROADCAST, BYPASS_PROXY];
Attribute.prototype = {
/**
* <p>
* Adds an attribute with the provided configuration to the host object.
* </p>
* <p>
* The config argument object supports the following properties:
* </p>
*
* <dl>
* <dt>value &#60;Any&#62;</dt>
* <dd>The initial value to set on the attribute</dd>
*
* <dt>valueFn &#60;Function&#62;</dt>
* <dd>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 defined, this precedence over the value property.</dd>
*
* <dt>readOnly &#60;boolean&#62;</dt>
* <dd>Whether or not the attribute is read only. Attributes having readOnly set to true
* cannot be modified by invoking the set method.</dd>
*
* <dt>writeOnce &#60;boolean&#62;</dt>
* <dd>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.</dd>
*
* <dt>setter &#60;Function&#62;</dt>
* <dd>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
* <a href="#property_Attribute.INVALID_VALUE">Attribute.INVALID_VALUE</a>, from the setter will prevent
* the value from being stored.</dd>
*
* <dt>getter &#60;Function&#62;</dt>
* <dd>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.</dd>
*
* <dt>validator &#60;Function&#62;</dt>
* <dd>The validator function invoked prior to setting the stored value. Returning
* false from the validator function will prevent the value from being stored.</dd>
*
* <dt>broadcast &#60;int&#62;</dt>
* <dd>If and how attribute change events for this attribute should be broadcast. See CustomEvent's <a href="CustomEvent.html#property_broadcast">broadcast</a> property for
* valid values. By default attribute change events are not broadcast.</dd>
*
* <dt>lazyAdd &#60;boolean&#62;</dt>
* <dd>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 <a href="#method_addAttrs">addAttrs</a> method.</dd>
*
* </dl>
*
* <p>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.</p>
*
* <p>Configuration properties outside of the list mentioned above are considered private properties used internally by attribute, and are not intended for public use.</p>
*
* @method addAttr
*
* @param {String} name The name of the attribute.
* @param {Object} config An object with attribute configuration property/value pairs, specifying the configuration for the attribute.
*
* <p>
* <strong>NOTE:</strong> 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.
* </p>
*
* @param {boolean} lazy (optional) Whether or not to add this attribute lazily (on the first call to get/set).
*
* @return {Object} A reference to the host object.
*
* @chainable
*/
addAttr: function(name, config, lazy) {
var host = this, // help compression
state = host._state,
value,
hasValue,
i, l, fn, fnRef;
lazy = (LAZY_ADD in config) ? config[LAZY_ADD] : lazy;
if (lazy && !host.attrAdded(name)) {
state.add(name, LAZY, config || {});
state.add(name, ADDED, true);
} else {
if (!host.attrAdded(name) || state.get(name, IS_LAZY_ADD)) {
config = config || {};
hasValue = (VALUE in config);
if(hasValue) {
// We'll go through set, don't want to set value in config directly
value = config.value;
delete config.value;
}
config.added = true;
config.initializing = true;
// String to fns
for (i = 0, l = FN_REFS.length; i < l; i++) {
fnRef = FN_REFS[i];
fn = config[fnRef];
if (fn && Lang.isString(fn)) {
config[fnRef] = this[fn];
}
}
state.addAll(name, config);
if (hasValue) {
// Go through set, so that raw values get normalized/validated
host.set(name, value);
}
state.remove(name, INITIALIZING);
}
}
return host;
},
/**
* Checks if the given attribute has been added to the host
*
* @method attrAdded
* @param {String} name The name of the attribute to check.
* @return {boolean} 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.
*/
attrAdded: function(name) {
return !!this._state.get(name, ADDED);
},
/**
* Updates the configuration of an attribute which has already been added.
* <p>
* 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.
* </p>
* @method modifyAttr
* @param {String} name The name of the attribute whose configuration is to be updated.
* @param {Object} config An object with configuration property/value pairs, specifying the configuration properties to modify.
*/
modifyAttr: function(name, config) {
var host = this, // help compression
prop, state;
if (host.attrAdded(name)) {
if (host._isLazyAttr(name)) {
host._addLazyAttr(name);
}
state = host._state;
for (prop in config) {
if (MODIFIABLE[prop] && config.hasOwnProperty(prop)) {
state.add(name, prop, config[prop]);
// If we reconfigured broadcast, need to republish
if (prop === BROADCAST) {
state.remove(name, PUBLISHED);
}
}
}
}
},
/**
* Removes an attribute from the host object
*
* @method removeAttr
* @param {String} name The name of the attribute to be removed.
*/
removeAttr: function(name) {
this._state.removeAll(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.
*
* @method get
*
* @param {String} name The 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. <code>get("x.y.z")</code>)
*
* @return {Any} The value of the attribute
*/
get : function(name) {
return this._getAttr(name);
},
/**
* Checks whether or not the attribute is one which has been
* added lazily and still requires initialization.
*
* @method _isLazyAttr
* @private
* @param {String} name The name of the attribute
* @return {boolean} true if it's a lazily added attribute, false otherwise.
*/
_isLazyAttr: function(name) {
return this._state.get(name, LAZY);
},
/**
* Finishes initializing an attribute which has been lazily added.
*
* @method _addLazyAttr
* @private
* @param {Object} name The name of the attribute
*/
_addLazyAttr: function(name) {
var state = this._state,
lazyCfg = state.get(name, LAZY);
state.add(name, IS_LAZY_ADD, true);
state.remove(name, LAZY);
this.addAttr(name, lazyCfg);
},
/**
* 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);
},
/**
* Resets the attribute (or all attributes) to its initial value, as long as
* the attribute is not readOnly, or writeOnce.
*
* @method reset
* @param {String} name Optional. The name of the attribute to reset. If omitted, all attributes are reset.
* @return {Object} A reference to the host object.
* @chainable
*/
reset : function(name) {
var host = this, // help compression
added;
if (name) {
if (host._isLazyAttr(name)) {
host._addLazyAttr(name);
}
host.set(name, host._state.get(name, INIT_VALUE));
} else {
added = host._state.data.added;
Y.each(added, function(v, n) {
host.reset(n);
}, host);
}
return host;
},
/**
* 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);
},
/**
* Provides the common implementation for the public get method,
* allowing Attribute hosts to over-ride either method.
*
* See <a href="#method_get">get</a> for argument details.
*
* @method _getAttr
* @protected
* @chainable
*
* @param {String} name The name of the attribute.
* @return {Any} The value of the attribute.
*/
_getAttr : function(name) {
var host = this, // help compression
fullName = name,
state = host._state,
path,
getter,
val,
cfg;
if (name.indexOf(DOT) !== -1) {
path = name.split(DOT);
name = path.shift();
}
// On Demand - Should be rare - handles out of order valueFn references
if (host._tCfgs && host._tCfgs[name]) {
cfg = {};
cfg[name] = host._tCfgs[name];
delete host._tCfgs[name];
host._addAttrs(cfg, host._tVals);
}
// Lazy Init
if (host._isLazyAttr(name)) {
host._addLazyAttr(name);
}
val = host._getStateVal(name);
getter = state.get(name, GETTER);
val = (getter) ? getter.call(host, val, fullName) : val;
val = (path) ? O.getValue(val, path) : val;
return val;
},
/**
* Provides the common implementation for the public set and protected _set methods.
*
* See <a href="#method_set">set</a> for argument details.
*
* @method _setAttr
* @protected
* @chainable
*
* @param {String} name The name of the attribute.
* @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.
* @param {boolean} force If true, allows the caller to set values for
* readOnly or writeOnce attributes which have already been set.
*
* @return {Object} A reference to the host object.
*/
_setAttr : function(name, val, opts, force) {
var allowSet = true,
state = this._state,
stateProxy = this._stateProxy,
data = state.data,
initialSet,
strPath,
path,
currVal;
if (name.indexOf(DOT) !== -1) {
strPath = name;
path = name.split(DOT);
name = path.shift();
}
if (this._isLazyAttr(name)) {
this._addLazyAttr(name);
}
initialSet = (!data.value || !(name in data.value));
if (stateProxy && name in stateProxy && !this._state.get(name, BYPASS_PROXY)) {
// TODO: Value is always set for proxy. Can we do any better? Maybe take a snapshot as the initial value for the first call to set?
initialSet = false;
}
if (this._requireAddAttr && !this.attrAdded(name)) {
} else {
if (!initialSet && !force) {
if (state.get(name, WRITE_ONCE)) {
allowSet = false;
}
if (state.get(name, READ_ONLY)) {
allowSet = false;
}
}
if (allowSet) {
// Don't need currVal if initialSet (might fail in custom getter if it always expects a non-undefined/non-null value)
if (!initialSet) {
currVal = this.get(name);
}
if (path) {
val = O.setValue(Y.clone(currVal), path, val);
if (val === undefined) {
allowSet = false;
}
}
if (allowSet) {
if (state.get(name, INITIALIZING)) {
this._setAttrVal(name, strPath, currVal, val);
} else {
this._fireAttrChange(name, strPath, currVal, val, 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.
*/
_fireAttrChange : function(attrName, subAttrName, currVal, newVal, opts) {
var host = this,
eventName = attrName + CHANGE,
state = host._state,
facade;
if (!state.get(attrName, PUBLISHED)) {
host.publish(eventName, {
queuable:false,
defaultFn:host._defAttrChangeFn,
silent:true,
broadcast : state.get(attrName, BROADCAST)
});
state.add(attrName, PUBLISHED, true);
}
facade = (opts) ? Y.merge(opts) : host._ATTR_E_FACADE;
facade.type = eventName;
facade.attrName = attrName;
facade.subAttrName = subAttrName;
facade.prevVal = currVal;
facade.newVal = newVal;
host.fire(facade);
},
/**
* Default function for attribute change events.
*
* @private
* @method _defAttrChangeFn
* @param {EventFacade} e The event object for attribute change events.
*/
_defAttrChangeFn : function(e) {
if (!this._setAttrVal(e.attrName, e.subAttrName, e.prevVal, e.newVal)) {
// Prevent "after" listeners from being invoked since nothing changed.
e.stopImmediatePropagation();
} else {
e.newVal = this._getStateVal(e.attrName);
}
},
/**
* Gets the stored value for the attribute, from either the
* internal state object, or the state proxy if it exits
*
* @method _getStateVal
* @private
* @param {String} name The name of the attribute
* @return {Any} The stored value of the attribute
*/
_getStateVal : function(name) {
var stateProxy = this._stateProxy;
return stateProxy && (name in stateProxy) && !this._state.get(name, BYPASS_PROXY) ? stateProxy[name] : this._state.get(name, VALUE);
},
/**
* Sets the stored value for the attribute, in either the
* internal state object, or the state proxy if it exits
*
* @method _setStateVal
* @private
* @param {String} name The name of the attribute
* @param {Any} value The value of the attribute
*/
_setStateVal : function(name, value) {
var stateProxy = this._stateProxy;
if (stateProxy && (name in stateProxy) && !this._state.get(name, BYPASS_PROXY)) {
stateProxy[name] = value;
} else {
this._state.add(name, VALUE, value);
}
},
/**
* Updates the stored value of the attribute in the privately held State object,
* if validation and setter passes.
*
* @method _setAttrVal
* @private
* @param {String} attrName The attribute name.
* @param {String} subAttrName The sub-attribute name, if setting a sub-attribute property ("x.y.z").
* @param {Any} prevVal The currently stored value of the attribute.
* @param {Any} newVal The value which is going to be stored.
*
* @return {booolean} true if the new attribute value was stored, false if not.
*/
_setAttrVal : function(attrName, subAttrName, prevVal, newVal) {
var host = this,
allowSet = true,
state = host._state,
validator = state.get(attrName, VALIDATOR),
setter = state.get(attrName, SETTER),
initializing = state.get(attrName, INITIALIZING),
prevValRaw = this._getStateVal(attrName),
name = subAttrName || attrName,
retVal,
valid;
if (validator) {
valid = validator.call(host, newVal, name);
if (!valid && initializing) {
newVal = state.get(attrName, DEF_VALUE);
valid = true; // Assume it's valid, for perf.
}
}
if (!validator || valid) {
if (setter) {
retVal = setter.call(host, newVal, name);
if (retVal === INVALID_VALUE) {
allowSet = false;
} else if (retVal !== undefined){
newVal = retVal;
}
}
if (allowSet) {
if(!subAttrName && (newVal === prevValRaw) && !Lang.isObject(newVal)) {
allowSet = false;
} else {
// Store value
if (state.get(attrName, INIT_VALUE) === undefined) {
state.add(attrName, INIT_VALUE, newVal);
}
host._setStateVal(attrName, newVal);
}
}
} else {
allowSet = false;
}
return allowSet;
},
/**
* Sets multiple attribute values.
*
* @method setAttrs
* @param {Object} attrs An object with attributes name/value pairs.
* @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.
* @return {Object} A reference to the host object.
* @chainable
*/
_setAttrs : function(attrs, opts) {
for (var attr in attrs) {
if ( attrs.hasOwnProperty(attr) ) {
this.set(attr, attrs[attr]);
}
}
return this;
},
/**
* Gets multiple attribute values.
*
* @method getAttrs
* @param {Array | boolean} attrs Optional. An array of attribute names. If omitted, all attribute values are
* returned. If set to true, all attributes modified from their initial values are returned.
* @return {Object} An object with attribute name/value pairs.
*/
getAttrs : function(attrs) {
return this._getAttrs(attrs);
},
/**
* Implementation behind the public getAttrs method, to get multiple attribute values.
*
* @method _getAttrs
* @protected
* @param {Array | boolean} attrs Optional. An array of attribute names. If omitted, all attribute values are
* returned. If set to true, all attributes modified from their initial values are returned.
* @return {Object} An object with attribute name/value pairs.
*/
_getAttrs : function(attrs) {
var host = this,
o = {},
i, l, attr, val,
modifiedOnly = (attrs === true);
attrs = (attrs && !modifiedOnly) ? attrs : O.keys(host._state.data.added);
for (i = 0, l = attrs.length; i < l; i++) {
// Go through get, to honor cloning/normalization
attr = attrs[i];
val = host.get(attr);
if (!modifiedOnly || host._getStateVal(attr) != host._state.get(attr, INIT_VALUE)) {
o[attr] = host.get(attr);
}
}
return o;
},
/**
* Configures a group of attributes, and sets initial values.
*
* <p>
* <strong>NOTE:</strong> This method does not isolate the configuration object by merging/cloning.
* The caller is responsible for merging/cloning the configuration object if required.
* </p>
*
* @method addAttrs
* @chainable
*
* @param {Object} cfgs An object with attribute name/configuration pairs.
* @param {Object} values An 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.
* @param {boolean} lazy Whether 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 <a href="#method_addAttr">addAttr</a>.
*
* @return {Object} A reference to the host object.
*/
addAttrs : function(cfgs, values, lazy) {
var host = this; // help compression
if (cfgs) {
host._tCfgs = cfgs;
host._tVals = host._normAttrVals(values);
host._addAttrs(cfgs, host._tVals, lazy);
host._tCfgs = host._tVals = null;
}
return host;
},
/**
* 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).
*
* @method _addAttrs
* @private
* @param {Object} cfgs An object with attribute name/configuration pairs.
* @param {Object} values An 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.
* @param {boolean} lazy Whether 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 <a href="#method_addAttr">addAttr</a>.
*/
_addAttrs : function(cfgs, values, lazy) {
var host = this, // help compression
attr,
attrCfg,
value;
for (attr in cfgs) {
if (cfgs.hasOwnProperty(attr)) {
// Not Merging. Caller is responsible for isolating configs
attrCfg = cfgs[attr];
attrCfg.defaultValue = attrCfg.value;
// Handle simple, complex and user values, accounting for read-only
value = host._getAttrInitVal(attr, attrCfg, host._tVals);
if (value !== undefined) {
attrCfg.value = value;
}
if (host._tCfgs[attr]) {
delete host._tCfgs[attr];
}
host.addAttr(attr, attrCfg, lazy);
}
}
},
/**
* Utility method to protect an attribute configuration
* hash, by merging the entire object and the individual
* attr config objects.
*
* @method _protectAttrs
* @protected
* @param {Object} attrs A hash of attribute to configuration object pairs.
* @return {Object} A protected version of the attrs argument.
*/
_protectAttrs : function(attrs) {
if (attrs) {
attrs = Y.merge(attrs);
for (var attr in attrs) {
if (attrs.hasOwnProperty(attr)) {
attrs[attr] = Y.merge(attrs[attr]);
}
}
}
return attrs;
},
/**
* Utility method to normalize attribute values. The base implementation
* simply merges the hash to protect the original.
*
* @method _normAttrVals
* @param {Object} valueHash An object with attribute name/value pairs
*
* @return {Object}
*
* @private
*/
_normAttrVals : function(valueHash) {
return (valueHash) ? Y.merge(valueHash) : null;
},
/**
* 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.
*
* @param {String} attr The name of the attribute
* @param {Object} cfg The attribute configuration object
* @param {Object} initValues The object with simple and complex attribute name/value pairs returned from _normAttrVals
*
* @return {Any} The initial value of the attribute.
*
* @method _getAttrInitVal
* @private
*/
_getAttrInitVal : function(attr, cfg, initValues) {
// init value is provided by the user if it exists, else, provided by the config
var val = (!cfg[READ_ONLY] && initValues && initValues.hasOwnProperty(attr)) ?
val = initValues[attr] :
(cfg[VALUE_FN]) ?
cfg[VALUE_FN].call(this) :
cfg[VALUE];
return val;
}
};
// Basic prototype augment - no lazy constructor invocation.
Y.mix(Attribute, EventTarget, false, null, 1);
Y.Attribute = Attribute;
}, '@VERSION@' ,{requires:['event-custom']});