#

API Docs for: 3.10.3
Show: Inherited Protected Private Deprecated

# File: attribute/js/AttributeCore.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-core submodule provides the lightest level of attribute handling support
         * without Attribute change events, or lesser used methods such as reset(), modifyAttrs(),
         * and removeAttr().
         *
         * @module attribute
         * @submodule attribute-core
         */
        var O = Y.Object,
            Lang = Y.Lang,

            DOT = ".",

            // Externally configurable props
            GETTER = "getter",
            SETTER = "setter",
            READ_ONLY = "readOnly",
            WRITE_ONCE = "writeOnce",
            INIT_ONLY = "initOnly",
            VALIDATOR = "validator",
            VALUE = "value",
            VALUE_FN = "valueFn",
            LAZY_ADD = "lazyAdd",

            // Used for internal state management
            ADDED = "added",
            BYPASS_PROXY = "_bypassProxy",
            INIT_VALUE = "initValue",
            LAZY = "lazy",

            INVALID_VALUE;

        /**
         * <p>
         * AttributeCore provides the lightest level of configurable attribute support. 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, <strong>but without support for attribute change events</strong>.
         * </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>Object/Classes based on AttributeCore can augment <a href="AttributeObservable.html">AttributeObservable</a>
         * (with true for overwrite) and <a href="AttributeExtras.html">AttributeExtras</a> to add attribute event and
         * additional, less commonly used attribute methods, such as `modifyAttr`, `removeAttr` and `reset`.</p>
         *
         * @class AttributeCore
         * @param attrs {Object} The attributes to add during construction (passed through to <a href="#method_addAttrs">addAttrs</a>).
         *        These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
         * @param values {Object} The initial attribute values to apply (passed through to <a href="#method_addAttrs">addAttrs</a>).
         *        These are not merged/cloned. The caller is responsible for isolating user provided values if required.
         * @param lazy {boolean} Whether or not to add attributes lazily (passed through to <a href="#method_addAttrs">addAttrs</a>).
         */
        function AttributeCore(attrs, values, lazy) {
            // HACK: Fix #2531929
            // Complete hack, to make sure the first clone of a node value in IE doesn't doesn't hurt state - maintains 3.4.1 behavior.
            // Too late in the release cycle to do anything about the core problem.
            // The root issue is that cloning a Y.Node instance results in an object which barfs in IE, when you access it's properties (since 3.3.0).
            this._yuievt = null;

            this._initAttrHost(attrs, values, lazy);
        }

        /**
         * <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
         * AttributeCore.INVALID_VALUE to prevent invalid values from being stored.</p>
         *
         * @property INVALID_VALUE
         * @type Object
         * @static
         * @final
         */
        AttributeCore.INVALID_VALUE = {};
        INVALID_VALUE = AttributeCore.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 _ATTR_CFG
         * @type Array
         * @static
         * @protected
         */
        AttributeCore._ATTR_CFG = [SETTER, GETTER, VALIDATOR, VALUE, VALUE_FN, WRITE_ONCE, READ_ONLY, LAZY_ADD, BYPASS_PROXY];

        /**
         * Utility method to protect an attribute configuration hash, by merging the
         * entire object and the individual attr config objects.
         *
         * @method protectAttrs
         * @static
         * @param {Object} attrs A hash of attribute to configuration object pairs.
         * @return {Object} A protected version of the `attrs` argument.
         */
        AttributeCore.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;
        };

        AttributeCore.prototype = {

            /**
             * Constructor logic for attributes. Initializes the host state, and sets up the inital attributes passed to the
             * constructor.
             *
             * @method _initAttrHost
             * @param attrs {Object} The attributes to add during construction (passed through to <a href="#method_addAttrs">addAttrs</a>).
             *        These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
             * @param values {Object} The initial attribute values to apply (passed through to <a href="#method_addAttrs">addAttrs</a>).
             *        These are not merged/cloned. The caller is responsible for isolating user provided values if required.
             * @param lazy {boolean} Whether or not to add attributes lazily (passed through to <a href="#method_addAttrs">addAttrs</a>).
             * @private
             */
            _initAttrHost : function(attrs, values, lazy) {
                this._state = new Y.State();
                this._initAttrs(attrs, values, lazy);
            },

            /**
             * <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 | String&#62;</dt>
             *    <dd>
             *    <p>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.</p>
             *
             *    <p>valueFn can also be set to a string, representing the name of the instance method to be used to retrieve the value.</p>
             *    </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; or &#60;string&#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.
             *        <p>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)</p>
             *    </dd>
             *
             *    <dt>setter &#60;Function | String&#62;</dt>
             *    <dd>
             *    <p>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.
             *    </p>
             *
             *    <p>setter can also be set to a string, representing the name of the instance method to be used as the setter function.</p>
             *    </dd>
             *
             *    <dt>getter &#60;Function | String&#62;</dt>
             *    <dd>
             *    <p>
             *    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.
             *    </p>
             *
             *    <p>getter can also be set to a string, representing the name of the instance method to be used as the getter function.</p>
             *    </dd>
             *
             *    <dt>validator &#60;Function | String&#62;</dt>
             *    <dd>
             *    <p>
             *    The validator function invoked prior to setting the stored value. Returning
             *    false from the validator function will prevent the value from being stored.
             *    </p>
             *
             *    <p>validator can also be set to a string, representing the name of the instance method to be used as the validator function.</p>
             *    </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) {

                Y.log('Adding attribute: ' + name, 'info', 'attribute');

                var host = this, // help compression
                    state = host._state,
                    data = state.data,
                    storedCfg = data[name],
                    value,
                    added,
                    hasValue;

                config = config || {};

                if (LAZY_ADD in config) {
                    lazy = config[LAZY_ADD];
                }

                added = state.get(name, ADDED);

                if (lazy && !added) {

                    // LAST MINUTE PRE 3.10.0 RELEASE WORKAROUND.

                    // Revisit for 3.11.0 with the planned change to add all attributes
                    // at once, instead of filtering for each class which is the root
                    // of the issue.

                    // This is to account for the case when an attribute value gets set,
                    // before it's actual config is added formally. We end up blowing away
                    // the previously set value in that case, with the config. Prior to
                    // the performance fixes, we just used to merge, so we didn't see the
                    // issue.

                    if (!storedCfg) {
                        storedCfg = data[name] = {};
                    }

                    storedCfg.lazy = config;
                    storedCfg.added = true;

                } else {

                    if (added && !config.isLazyAdd) { Y.log('Attribute: ' + name + ' already exists. Cannot add it again without removing it first', 'warn', 'attribute'); }

                    if (!added || config.isLazyAdd) {

                        hasValue = (VALUE in config);

                        if (config.readOnly && !hasValue) { Y.log('readOnly attribute: ' + name + ', added without an initial value. Value will be set on initial call to set', 'warn', 'attribute');}

                        if (hasValue) {

                            // We'll go through set, don't want to set value in config directly

                            // PERF TODO: VALIDATE: See if setting this to undefined is sufficient. We use to delete before.
                            // In certain code paths/use cases, undefined may not be the same as not present.
                            // If not, we can set it to some known fixed value (like INVALID_VALUE, say INITIALIZING_VALUE) for performance,
                            // to avoid a delete which seems to help a lot.

                            value = config.value;
                            config.value = undefined;
                        } else {
                            // LAST MINUTE PRE 3.10.0 RELEASE WORKAROUND.
                            if (storedCfg && (VALUE in storedCfg)) {
                                config.value = storedCfg.value;
                            }
                        }

                        config.added = true;
                        config.initializing = true;

                        data[name] = config;

                        if (hasValue) {
                            // Go through set, so that raw values get normalized/validated
                            host.set(name, value);
                        }

                        config.initializing = false;
                    }
                }

                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));
            },

            /**
             * 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
             * @param {Object} [lazyCfg] Optional config hash for the attribute. This is added for performance
             * along the critical path, where the calling method has already obtained lazy config from state.
             */
            _addLazyAttr: function(name, lazyCfg) {
                var state = this._state;

                lazyCfg = lazyCfg || state.get(name, LAZY);

                if (lazyCfg) {

                    // PERF TODO: For App's id override, otherwise wouldn't be
                    // needed. It expects to find it in the cfg for it's
                    // addAttr override. Would like to remove, once App override is
                    // removed.
                    state.data[name].lazy = undefined;

                    lazyCfg.isLazyAdd = true;

                    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 data providing the circumstances for the change.
             * @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 data providing the circumstances for the change.
             * @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 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 data providing the circumstances for the change.
             * @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,
                    cfg,
                    initialSet,
                    strPath,
                    path,
                    currVal,
                    writeOnce,
                    initializing;

                if (name.indexOf(DOT) !== -1) {
                    strPath = name;

                    path = name.split(DOT);
                    name = path.shift();
                }

                cfg = state.data[name] || {};

                if (cfg.lazy) {
                    cfg = cfg.lazy;
                    this._addLazyAttr(name, cfg);
                }

                initialSet = (cfg.value === undefined);

                if (stateProxy && name in stateProxy && !cfg._bypassProxy) {
                    // 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;
                }

                writeOnce = cfg.writeOnce;
                initializing = cfg.initializing;

                if (!initialSet && !force) {

                    if (writeOnce) {
                        Y.log('Set attribute:' + name + ', aborted; Attribute is writeOnce', 'warn', 'attribute');
                        allowSet = false;
                    }

                    if (cfg.readOnly) {
                        Y.log('Set attribute:' + name + ', aborted; Attribute is readOnly', 'warn', 'attribute');
                        allowSet = false;
                    }
                }

                if (!initializing && !force && writeOnce === INIT_ONLY) {
                    Y.log('Set attribute:' + name + ', aborted; Attribute is writeOnce: "initOnly"', 'warn', 'attribute');
                    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) {
                           Y.log('Set attribute path:' + strPath + ', aborted; Path is invalid', 'warn', 'attribute');
                           allowSet = false;
                       }
                    }

                    if (allowSet) {
                        if (!this._fireAttrChange || initializing) {
                            this._setAttrVal(name, strPath, currVal, val, opts, cfg);
                        } else {
                            // HACK - no real reason core needs to know about _fireAttrChange, but
                            // it adds fn hops if we want to break it out. Not sure it's worth it for this critical path
                            this._fireAttrChange(name, strPath, currVal, val, opts, cfg);
                        }
                    }
                }

                return this;
            },

            /**
             * 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 fullName = name,
                    tCfgs    = this._tCfgs,
                    path,
                    getter,
                    val,
                    attrCfg,
                    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 (tCfgs && tCfgs[name]) {
                    cfg = {};
                    cfg[name] = tCfgs[name];
                    delete tCfgs[name];
                    this._addAttrs(cfg, this._tVals);
                }

                attrCfg = this._state.data[name] || {};

                // Lazy Init
                if (attrCfg.lazy) {
                    attrCfg = attrCfg.lazy;
                    this._addLazyAttr(name, attrCfg);
                }

                val = this._getStateVal(name, attrCfg);

                getter = attrCfg.getter;

                if (getter && !getter.call) {
                    getter = this[getter];
                }

                val = (getter) ? getter.call(this, val, fullName) : val;
                val = (path) ? O.getValue(val, path) : val;

                return val;
            },

            /**
             * 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
             * @param {Object} [cfg] Optional 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.
             *
             * @return {Any} The stored value of the attribute
             */
            _getStateVal : function(name, cfg) {
                var stateProxy = this._stateProxy;

                if (!cfg) {
                    cfg = this._state.getAll(name) || {};
                }

                return (stateProxy && (name in stateProxy) && !(cfg._bypassProxy)) ? stateProxy[name] : cfg.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.
             * @param {Object} [opts] Optional data providing the circumstances for the change.
             * @param {Object} [attrCfg] Optional 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.
             *
             * @return {booolean} true if the new attribute value was stored, false if not.
             */
            _setAttrVal : function(attrName, subAttrName, prevVal, newVal, opts, attrCfg) {

                var host = this,
                    allowSet = true,
                    cfg = attrCfg || this._state.data[attrName] || {},
                    validator = cfg.validator,
                    setter = cfg.setter,
                    initializing = cfg.initializing,
                    prevRawVal = this._getStateVal(attrName, cfg),
                    name = subAttrName || attrName,
                    retVal,
                    valid;

                if (validator) {
                    if (!validator.call) {
                        // Assume string - trying to keep critical path tight, so avoiding Lang check
                        validator = this[validator];
                    }
                    if (validator) {
                        valid = validator.call(host, newVal, name, opts);

                        if (!valid && initializing) {
                            newVal = cfg.defaultValue;
                            valid = true; // Assume it's valid, for perf.
                        }
                    }
                }

                if (!validator || valid) {
                    if (setter) {
                        if (!setter.call) {
                            // Assume string - trying to keep critical path tight, so avoiding Lang check
                            setter = this[setter];
                        }
                        if (setter) {
                            retVal = setter.call(host, newVal, name, opts);

                            if (retVal === INVALID_VALUE) {
                                if (initializing) {
                                    Y.log('Attribute: ' + attrName + ', setter returned Attribute.INVALID_VALUE for value:' + newVal + ', initializing to default value', 'warn', 'attribute');
                                    newVal = cfg.defaultValue;
                                } else {
                                    Y.log('Attribute: ' + attrName + ', setter returned Attribute.INVALID_VALUE for value:' + newVal, 'warn', 'attribute');
                                    allowSet = false;
                                }
                            } else if (retVal !== undefined){
                                Y.log('Attribute: ' + attrName + ', raw value: ' + newVal + ' modified by setter to:' + retVal, 'info', 'attribute');
                                newVal = retVal;
                            }
                        }
                    }

                    if (allowSet) {
                        if(!subAttrName && (newVal === prevRawVal) && !Lang.isObject(newVal)) {
                            Y.log('Attribute: ' + attrName + ', value unchanged:' + newVal, 'warn', 'attribute');
                            allowSet = false;
                        } else {
                            // Store value
                            if (!(INIT_VALUE in cfg)) {
                                cfg.initValue = newVal;
                            }
                            host._setStateVal(attrName, newVal);
                        }
                    }

                } else {
                    Y.log('Attribute:' + attrName + ', Validation failed for value:' + newVal, 'warn', 'attribute');
                    allowSet = false;
                }

                return allowSet;
            },

            /**
             * Sets multiple attribute values.
             *
             * @method setAttrs
             * @param {Object} attrs  An object with attributes name/value pairs.
             * @param {Object} [opts] Optional data providing the circumstances for the change.
             * @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] Optional data providing the circumstances for the change
             * @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;
            },

            /**
             * 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 obj = {},
                    attr, i, len,
                    modifiedOnly = (attrs === true);

                // TODO - figure out how to get all "added"
                if (!attrs || modifiedOnly) {
                    attrs = O.keys(this._state.data);
                }

                for (i = 0, len = attrs.length; i < len; i++) {
                    attr = attrs[i];

                    if (!modifiedOnly || this._getStateVal(attr) != this._state.get(attr, INIT_VALUE)) {
                        // Go through get, to honor cloning/normalization
                        obj[attr] = this.get(attr);
                    }
                }

                return obj;
            },

            /**
             * 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) {
                if (cfgs) {
                    this._tCfgs = cfgs;
                    this._tVals = (values) ? this._normAttrVals(values) : null;
                    this._addAttrs(cfgs, this._tVals, lazy);
                    this._tCfgs = this._tVals = null;
                }

                return this;
            },

            /**
             * 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 tCfgs = this._tCfgs,
                    tVals = this._tVals,
                    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 = this._getAttrInitVal(attr, attrCfg, tVals);

                        if (value !== undefined) {
                            attrCfg.value = value;
                        }

                        if (tCfgs[attr]) {
                            tCfgs[attr] = undefined;
                        }

                        this.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.
             * @deprecated Use `AttributeCore.protectAttrs()` or
             *   `Attribute.protectAttrs()` which are the same static utility method.
             */
            _protectAttrs : AttributeCore.protectAttrs,

            /**
             * 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} 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.
             *
             * @private
             */
            _normAttrVals : function(valueHash) {
                var vals,
                    subvals,
                    path,
                    attr,
                    v, k;

                if (!valueHash) {
                    return null;
                }

                vals = {};

                for (k in valueHash) {
                    if (valueHash.hasOwnProperty(k)) {
                        if (k.indexOf(DOT) !== -1) {
                            path = k.split(DOT);
                            attr = path.shift();

                            subvals = subvals || {};

                            v = subvals[attr] = subvals[attr] || [];
                            v[v.length] = {
                                path : path,
                                value: valueHash[k]
                            };
                        } else {
                            vals[k] = valueHash[k];
                        }
                    }
                }

                return { simple:vals, complex:subvals };
            },

            /**
             * 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) {
                var val = cfg.value,
                    valFn = cfg.valueFn,
                    tmpVal,
                    initValSet = false,
                    readOnly = cfg.readOnly,
                    simple,
                    complex,
                    i,
                    l,
                    path,
                    subval,
                    subvals;

                if (!readOnly && initValues) {
                    // Simple Attributes
                    simple = initValues.simple;
                    if (simple && simple.hasOwnProperty(attr)) {
                        val = simple[attr];
                        initValSet = true;
                    }
                }

                if (valFn && !initValSet) {
                    if (!valFn.call) {
                        valFn = this[valFn];
                    }
                    if (valFn) {
                        tmpVal = valFn.call(this, attr);
                        val = tmpVal;
                    }
                }

                if (!readOnly && initValues) {

                    // Complex Attributes (complex values applied, after simple, in case both are set)
                    complex = initValues.complex;

                    if (complex && complex.hasOwnProperty(attr) && (val !== undefined) && (val !== null)) {
                        subvals = complex[attr];
                        for (i = 0, l = subvals.length; i < l; ++i) {
                            path = subvals[i].path;
                            subval = subvals[i].value;
                            O.setValue(val, path, subval);
                        }
                    }
                }

                return val;
            },

            /**
             * Utility method to set up initial attributes defined during construction,
             * either through the constructor.ATTRS property, or explicitly passed in.
             *
             * @method _initAttrs
             * @protected
             * @param attrs {Object} The attributes to add during construction (passed through to <a href="#method_addAttrs">addAttrs</a>).
             *        These can also be defined on the constructor being augmented with Attribute by defining the ATTRS property on the constructor.
             * @param values {Object} The initial attribute values to apply (passed through to <a href="#method_addAttrs">addAttrs</a>).
             *        These are not merged/cloned. The caller is responsible for isolating user provided values if required.
             * @param lazy {boolean} Whether or not to add attributes lazily (passed through to <a href="#method_addAttrs">addAttrs</a>).
             */
            _initAttrs : function(attrs, values, lazy) {
                // ATTRS support for Node, which is not Base based
                attrs = attrs || this.constructor.ATTRS;

                var Base = Y.Base,
                    BaseCore = Y.BaseCore,
                    baseInst = (Base && Y.instanceOf(this, Base)),
                    baseCoreInst = (!baseInst && BaseCore && Y.instanceOf(this, BaseCore));

                if (attrs && !baseInst && !baseCoreInst) {
                    this.addAttrs(Y.AttributeCore.protectAttrs(attrs), values, lazy);
                }
            }
        };

        Y.AttributeCore = AttributeCore;