jsbeans

/*!
 * Copyright (c) 2009 Francesco Mele jsbeans@francescomele.com
 *
 * This Software is licenced under the LGPL Licence (GNU Lesser General 
 * Public License).
 * In addition to the LGPL Licence the Software is subject to the 
 * following conditions:
 * 
 * 	i	every modification must be public and comunicated to the Author
 * 	ii	every "jsbean" added to this library must be self consistent 
 * 		except for the dependence from jsbeans-x.x.x.js
 * 	iii	copyright notice and this permission notice shall be included 
 * 		in all copies or substantial portions of the Software
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
/**
 * A collection of utilities in Javascript Object fashion
 * @module jsbeans
 */

/**
 * Implementation of base Object used as namespace
 * @class jsbeans
 * @static
 */
jsbeans = {
	/**
	 * Create a full qualified Object (namespace included) from a string
	 * @method define
	 * @param {String} pckName
	 * @static
	 */
	define: function(pckName) {
		var node = window;
		var v = pckName.split(".");
		for (var i = 0; i < v.length; i++) {
			var p = v[i];
			if (node[p] == null) {
				node[p] = new window.Object();
			}
			node = node[p];
		}
	    // no need to return it
		//return node;
	},
	/**
	 * @private
	 * */
	_alreadyLoaded: new Array(),
	/**
	 * Loads a 'jsbean' appending the <code>script</code> tag at the head of current page.<br/>
	 * An optional function, passed as second argument, may be invoked as callback after the jsbean has been loaded. It tries each 100 milliseconds for 5 seconds (configurable).
	 * @param jsbean {String} jsbean's name.
	 * @param [func] {Function} A callback fired after the jsbean has been loaded. Optional.
	 * @param [until] {Integer} Maximum number of seconds to try invoking the callback. Optional (default: 5).
	 * @static
	 * */
	load: function(jsbean) {
		var callback = arguments[1] || null;
		var until = arguments[2] || 5;
		if (!jsbeans._alreadyLoaded[jsbean]) {
			var o = eval("jsbeans." + jsbean);
			if (!o) {
				var scripts = document.getElementsByTagName("script");
				var _realLoad = function(m, jsbean) {
					var root = src.substring(0, m.index);
					var jsbeanSrc = root + "jsbeans/" + jsbean + ".js";
					try {
						var jsbeanScript = document.createElement("script");
						jsbeanScript.src = jsbeanSrc;
						document.getElementsByTagName("head")[0].appendChild(jsbeanScript);
//						document.write("<scr"+"ipt type='text/javascript' src='" + jsbeanSrc + "'><!-- --></scr"+"ipt>");
					} 
					catch (e) {
					}
					jsbeans._alreadyLoaded[jsbean] = true;
				};
				var re = /jsbeans\.js([\?\.]|$)/i;
				var re2 = new RegExp("jsbeans-latest\.js([\?\.]|$)", "i");
				for (var i = 0, script; script = scripts[i]; i++) {
					var src = script.getAttribute("src");
					if (src) {
						var m = src.match(re);
						if (m) {
							_realLoad(m, jsbean);
							break;
						} 
						else {
							m = src.match(re2);
							if (m) {
								_realLoad(m, jsbean);
								break;
							}
						}
					}
				}
			}
		}
		// fire the callback, if provided
		if (callback != null) {
			// from seconds to millis
			until = until * 1000;
			// interval
			var each = 100;
			var timer = 0;
			var callbackID = setInterval(function() {
				var b = eval("jsbeans." + jsbean);
				if (typeof b != "undefined") {
					try {
						callback();
					}
					catch(e) {}
					clearInterval(callbackID);
				}
				// update timer
				else {
					timer += each;
				}
				// clearInterval if timer exceeds the maximum allowed
				if (timer >= until) {
					clearInterval(callbackID);
				}
			}, each);
		}

	},
	/**
	 * If you find namespace annoying and verbose, you can use this method to define an alternative to jsbeans global Object.<br/>
	 * Sample:<pre>
	 * // before
	 * jsbeans.string.trimLeft("   string to trim");
	 * // call alias
	 * jsbeans.alias("jsb");
	 * // after
	 * jsb.string.trimLeft("   string to trim");
	 * </pre>
	 * Note that if {@param} <code class="param">newBase</code> is null, empty or already defined this method will exit silently
	 * @method alias
	 * @param newBase {String} a global variable used as alias for jsbeans global Object
	 * */
	alias: function(newBase) {
		if (newBase == null 
				// trimmed
				|| newBase.replace(/^\s\s*/, '').replace(/\s\s*$/, '') == ""
				// already defined
				|| typeof window[newBase] != "undefined") {
			return;
		}
		eval(newBase + " = jsbeans;");
	}
};