/*                                                                                                                                                      

Copyright (c) 2006, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 0.12.1

*/ 

/**

 * The YAHOO object is the single global object used by YUI Library.  It

 * contains utility function for setting up namespaces, inheritance, and

 * logging.  YAHOO.util, YAHOO.widget, and YAHOO.example are namespaces

 * created automatically for and used by the library.

 * @module yahoo

 * @title  YAHOO Global

 */



if (typeof YAHOO == "undefined") {

    /**

     * The YAHOO global namespace object

     * @class YAHOO

     * @static

     */

    var YAHOO = {};

}



/**

 * Returns the namespace specified and creates it if it doesn't exist

 * <pre>

 * YAHOO.namespace("property.package");

 * YAHOO.namespace("YAHOO.property.package");

 * </pre>

 * Either of the above would create YAHOO.property, then

 * YAHOO.property.package

 *

 * Be careful when naming packages. Reserved words may work in some browsers

 * and not others. For instance, the following will fail in Safari:

 * <pre>

 * YAHOO.namespace("really.long.nested.namespace");

 * </pre>

 * This fails because "long" is a future reserved word in ECMAScript

 *

 * @method namespace

 * @static

 * @param  {String*} arguments 1-n namespaces to create 

 * @return {Object}  A reference to the last namespace object created

 */

YAHOO.namespace = function() {

    var a=arguments, o=null, i, j, d;

    for (i=0; i<a.length; ++i) {

        d=a[i].split(".");

        o=YAHOO;



        // YAHOO is implied, so it is ignored if it is included

        for (j=(d[0] == "YAHOO") ? 1 : 0; j<d.length; ++j) {

            o[d[j]]=o[d[j]] || {};

            o=o[d[j]];

        }

    }



    return o;

};



/**

 * Uses YAHOO.widget.Logger to output a log message, if the widget is available.

 *

 * @method log

 * @static

 * @param  {String}  msg  The message to log.

 * @param  {String}  cat  The log category for the message.  Default

 *                        categories are "info", "warn", "error", time".

 *                        Custom categories can be used as well. (opt)

 * @param  {String}  src  The source of the the message (opt)

 * @return {Boolean}      True if the log operation was successful.

 */

YAHOO.log = function(msg, cat, src) {

    var l=YAHOO.widget.Logger;

    if(l && l.log) {

        return l.log(msg, cat, src);

    } else {

        return false;

    }

};



/**

 * Utility to set up the prototype, constructor and superclass properties to

 * support an inheritance strategy that can chain constructors and methods.

 *

 * @method extend

 * @static

 * @param {Function} subc   the object to modify

 * @param {Function} superc the object to inherit

 * @param {Object} overrides  additional properties/methods to add to the

 *                              subclass prototype.  These will override the

 *                              matching items obtained from the superclass 

 *                              if present.

 */

YAHOO.extend = function(subc, superc, overrides) {

    var F = function() {};

    F.prototype=superc.prototype;

    subc.prototype=new F();

    subc.prototype.constructor=subc;

    subc.superclass=superc.prototype;

    if (superc.prototype.constructor == Object.prototype.constructor) {

        superc.prototype.constructor=superc;

    }



    if (overrides) {

        for (var i in overrides) {

            subc.prototype[i]=overrides[i];

        }

    }

};



/**

 * Applies all prototype properties in the supplier to the receiver if the

 * receiver does not have these properties yet.  Optionally, one or more

 * methods/properties can be specified (as additional parameters).  This

 * option will overwrite the property if receiver has it already.

 *

 * @method augment

 * @static

 * @param {Function} r  the object to receive the augmentation

 * @param {Function} s  the object that supplies the properties to augment

 * @param {String*}  arguments zero or more properties methods to augment the

 *                             receiver with.  If none specified, everything

 *                             in the supplier will be used unless it would

 *                             overwrite an existing property in the receiver

 */

YAHOO.augment = function(r, s) {

    var rp=r.prototype, sp=s.prototype, a=arguments, i, p;

    if (a[2]) {

        for (i=2; i<a.length; ++i) {

            rp[a[i]] = sp[a[i]];

        }

    } else {

        for (p in sp) { 

            if (!rp[p]) {

                rp[p] = sp[p];

            }

        }

    }

};



YAHOO.namespace("util", "widget", "example");