# Yahoo! UI Library

### element 2.8.2r1

Yahoo! UI Library > element > AttributeProvider.js (source view)
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    (function() {
        var Lang = YAHOO.util.Lang;

        /*
        Copyright (c) 2006, Yahoo! Inc. All rights reserved.
        Code licensed under the BSD License:
        http://developer.yahoo.net/yui/license.txt
        */

        /**
         * Provides and manages YAHOO.util.Attribute instances
         * @namespace YAHOO.util
         * @class AttributeProvider
         * @uses YAHOO.util.EventProvider
         */
        YAHOO.util.AttributeProvider = function() {};

        YAHOO.util.AttributeProvider.prototype = {

            /**
             * A key-value map of Attribute configurations
             * @property _configs
             * @protected (may be used by subclasses and augmentors)
             * @private
             * @type {Object}
             */
            _configs: null,
            /**
             * Returns the current value of the attribute.
             * @method get
             * @param {String} key The attribute whose value will be returned.
             * @return {Any} The current value of the attribute.
             */
            get: function(key){
                this._configs = this._configs || {};
                var config = this._configs[key];

                if (!config || !this._configs.hasOwnProperty(key)) {
                    YAHOO.log(key + ' not found', 'error', 'AttributeProvider');
                    return null;
                }

                return config.getValue();
            },

            /**
             * Sets the value of a config.
             * @method set
             * @param {String} key The name of the attribute
             * @param {Any} value The value to apply to the attribute
             * @param {Boolean} silent Whether or not to suppress change events
             * @return {Boolean} Whether or not the value was set.
             */
            set: function(key, value, silent){
                this._configs = this._configs || {};
                var config = this._configs[key];

                if (!config) {
                    YAHOO.log('set failed: ' + key + ' not found',
                            'error', 'AttributeProvider');
                    return false;
                }

                return config.setValue(value, silent);
            },

            /**
             * Returns an array of attribute names.
             * @method getAttributeKeys
             * @return {Array} An array of attribute names.
             */
            getAttributeKeys: function(){
                this._configs = this._configs;
                var keys = [], key;

                for (key in this._configs) {
                    if ( Lang.hasOwnProperty(this._configs, key) &&
                            !Lang.isUndefined(this._configs[key]) ) {
                        keys[keys.length] = key;
                    }
                }

                return keys;
            },

            /**
             * Sets multiple attribute values.
             * @method setAttributes
             * @param {Object} map  A key-value map of attributes
             * @param {Boolean} silent Whether or not to suppress change events
             */
            setAttributes: function(map, silent){
                for (var key in map) {
                    if ( Lang.hasOwnProperty(map, key) ) {
                        this.set(key, map[key], silent);
                    }
                }
            },

            /**
             * Resets the specified attribute's value to its initial value.
             * @method resetValue
             * @param {String} key The name of the attribute
             * @param {Boolean} silent Whether or not to suppress change events
             * @return {Boolean} Whether or not the value was set
             */
            resetValue: function(key, silent){
                this._configs = this._configs || {};
                if (this._configs[key]) {
                    this.set(key, this._configs[key]._initialConfig.value, silent);
                    return true;
                }
                return false;
            },

            /**
             * Sets the attribute's value to its current value.
             * @method refresh
             * @param {String | Array} key The attribute(s) to refresh
             * @param {Boolean} silent Whether or not to suppress change events
             */
            refresh: function(key, silent) {
                this._configs = this._configs || {};
                var configs = this._configs;

                key = ( ( Lang.isString(key) ) ? [key] : key ) ||
                        this.getAttributeKeys();

                for (var i = 0, len = key.length; i < len; ++i) {
                    if (configs.hasOwnProperty(key[i])) {
                        this._configs[key[i]].refresh(silent);
                    }
                }
            },

            /**
             * Adds an Attribute to the AttributeProvider instance.
             * @method register
             * @param {String} key The attribute's name
             * @param {Object} map A key-value map containing the
             * attribute's properties.
             * @deprecated Use setAttributeConfig
             */
            register: function(key, map) {
                this.setAttributeConfig(key, map);
            },

            /**
             * Returns the attribute's properties.
             * @method getAttributeConfig
             * @param {String} key The attribute's name
             * @private
             * @return {object} A key-value map containing all of the
             * attribute's properties.
             */
            getAttributeConfig: function(key) {
                this._configs = this._configs || {};
                var config = this._configs[key] || {};
                var map = {}; // returning a copy to prevent overrides

                for (key in config) {
                    if ( Lang.hasOwnProperty(config, key) ) {
                        map[key] = config[key];
                    }
                }

                return map;
            },

            /**
             * Sets or updates an Attribute instance's properties.
             * @method setAttributeConfig
             * @param {String} key The attribute's name.
             * @param {Object} map A key-value map of attribute properties
             * @param {Boolean} init Whether or not this should become the intial config.
             */
            setAttributeConfig: function(key, map, init) {
                this._configs = this._configs || {};
                map = map || {};
                if (!this._configs[key]) {
                    map.name = key;
                    this._configs[key] = this.createAttribute(map);
                } else {
                    this._configs[key].configure(map, init);
                }
            },

            /**
             * Sets or updates an Attribute instance's properties.
             * @method configureAttribute
             * @param {String} key The attribute's name.
             * @param {Object} map A key-value map of attribute properties
             * @param {Boolean} init Whether or not this should become the intial config.
             * @deprecated Use setAttributeConfig
             */
            configureAttribute: function(key, map, init) {
                this.setAttributeConfig(key, map, init);
            },

            /**
             * Resets an attribute to its intial configuration.
             * @method resetAttributeConfig
             * @param {String} key The attribute's name.
             * @private
             */
            resetAttributeConfig: function(key){
                this._configs = this._configs || {};
                this._configs[key].resetConfig();
            },

            // wrapper for EventProvider.subscribe
            // to create events on the fly
            subscribe: function(type, callback) {
                this._events = this._events || {};

                if ( !(type in this._events) ) {
                    this._events[type] = this.createEvent(type);
                }

                YAHOO.util.EventProvider.prototype.subscribe.apply(this, arguments);
            },

            on: function() {
                this.subscribe.apply(this, arguments);
            },

            addListener: function() {
                this.subscribe.apply(this, arguments);
            },

            /**
             * Fires the attribute's beforeChange event.
             * @method fireBeforeChangeEvent
             * @param {String} key The attribute's name.
             * @param {Obj} e The event object to pass to handlers.
             */
            fireBeforeChangeEvent: function(e) {
                var type = 'before';
                type += e.type.charAt(0).toUpperCase() + e.type.substr(1) + 'Change';
                e.type = type;
                return this.fireEvent(e.type, e);
            },

            /**
             * Fires the attribute's change event.
             * @method fireChangeEvent
             * @param {String} key The attribute's name.
             * @param {Obj} e The event object to pass to the handlers.
             */
            fireChangeEvent: function(e) {
                e.type += 'Change';
                return this.fireEvent(e.type, e);
            },

            createAttribute: function(map) {
                return new YAHOO.util.Attribute(map, this);
            }
        };

        YAHOO.augment(YAHOO.util.AttributeProvider, YAHOO.util.EventProvider);
    })();

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