OpenAjax.js

/*******************************************************************************
* OpenAjax.js
*
* Reference implementation of the OpenAjax Hub, as specified by OpenAjax Alliance.
* Specification is under development at: 
*
*   http://www.openajax.org/member/wiki/OpenAjax_Hub_Specification
*
* Copyright 2006-2009 OpenAjax Alliance
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not 
* use this file except in compliance with the License. You may obtain a copy 
* of the License at http://www.apache.org/licenses/LICENSE-2.0 . Unless 
* required by applicable law or agreed to in writing, software distributed 
* under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 
* CONDITIONS OF ANY KIND, either express or implied. See the License for the 
* specific language governing permissions and limitations under the License.
*
******************************************************************************/

// prevent re-definition of the OpenAjax object
if (!window["OpenAjax"]) {
	OpenAjax = new function () {
		var t = true;
		var f = false;
		var g = window;
		var ooh = "org.openajax.hub.";

		var h = {};
		this.hub = h;
		h.implementer = "http://openajax.org";
		h.implVersion = "2.0";
		h.specVersion = "2.0";
		h.implExtraData = {};
		var libs = {};
		h.libraries = libs;

		h.registerLibrary = function (prefix, nsURL, version, extra) {
			libs[prefix] = {
				prefix: prefix,
				namespaceURI: nsURL,
				version: version,
				extraData: extra
			};
			this.publish(ooh + "registerLibrary", libs[prefix]);
		}
		h.unregisterLibrary = function (prefix) {
			this.publish(ooh + "unregisterLibrary", libs[prefix]);
			delete libs[prefix];
		}

		h._subscriptions = { c: {}, s: [] };
		h._cleanup = [];
		h._subIndex = 0;
		h._pubDepth = 0;

		h.subscribe = function (name, callback, scope, subscriberData, filter) {
			if (!scope) {
				scope = window;
			}
			var handle = name + "." + this._subIndex;
			var sub = { scope: scope, cb: callback, fcb: filter, data: subscriberData, sid: this._subIndex++, hdl: handle };
			var path = name.split(".");
			this._subscribe(this._subscriptions, path, 0, sub);
			return handle;
		}

		h.publish = function (name, message) {
			var path = name.split(".");
			this._pubDepth++;
			this._publish(this._subscriptions, path, 0, name, message);
			this._pubDepth--;
			if ((this._cleanup.length > 0) && (this._pubDepth == 0)) {
				for (var i = 0; i < this._cleanup.length; i++)
					this.unsubscribe(this._cleanup[i].hdl);
				delete (this._cleanup);
				this._cleanup = [];
			}
		}

		h.unsubscribe = function (sub) {
			var path = sub.split(".");
			var sid = path.pop();
			this._unsubscribe(this._subscriptions, path, 0, sid);
		}

		h._subscribe = function (tree, path, index, sub) {
			var token = path[index];
			if (index == path.length)
				tree.s.push(sub);
			else {
				if (typeof tree.c == "undefined")
					tree.c = {};
				if (typeof tree.c[token] == "undefined") {
					tree.c[token] = { c: {}, s: [] };
					this._subscribe(tree.c[token], path, index + 1, sub);
				}
				else
					this._subscribe(tree.c[token], path, index + 1, sub);
			}
		}

		h._publish = function (tree, path, index, name, msg, pid) {
			if (typeof tree != "undefined") {
				var node;
				if (index == path.length) {
					node = tree;
				} else {
					this._publish(tree.c[path[index]], path, index + 1, name, msg, pid);
					this._publish(tree.c["*"], path, index + 1, name, msg, pid);
					node = tree.c["**"];
				}
				if (typeof node != "undefined") {
					var callbacks = node.s;
					var max = callbacks.length;
					for (var i = 0; i < max; i++) {
						if (callbacks[i].cb) {
							var sc = callbacks[i].scope;
							var cb = callbacks[i].cb;
							var fcb = callbacks[i].fcb;
							var d = callbacks[i].data;
							if (typeof cb == "string") {
								// get a function object
								cb = sc[cb];
							}
							if (typeof fcb == "string") {
								// get a function object
								fcb = sc[fcb];
							}
							if ((!fcb) || (fcb.call(sc, name, msg, d))) {
								cb.call(sc, name, msg, d, pid);
							}
						}
					}
				}
			}
		}

		h._unsubscribe = function (tree, path, index, sid) {
			if (typeof tree != "undefined") {
				if (index < path.length) {
					var childNode = tree.c[path[index]];
					this._unsubscribe(childNode, path, index + 1, sid);
					if (childNode.s.length == 0) {
						for (var x in childNode.c)
							return;
						delete tree.c[path[index]];
					}
					return;
				}
				else {
					var callbacks = tree.s;
					var max = callbacks.length;
					for (var i = 0; i < max; i++)
						if (sid == callbacks[i].sid) {
							if (this._pubDepth > 0) {
								callbacks[i].cb = null;
								this._cleanup.push(callbacks[i]);
							}
							else
								callbacks.splice(i, 1);
							return;
						}
				}
			}
		}
		// The following function is provided for automatic testing purposes.
		// It is not expected to be deployed in run-time OpenAjax Hub implementations.
		h.reinit = function () {
			for (var lib in OpenAjax.hub.libraries) {
				delete OpenAjax.hub.libraries[lib];
			}
			OpenAjax.hub.registerLibrary("OpenAjax", "http://openajax.org/hub", "1.0", {});

			delete OpenAjax._subscriptions;
			OpenAjax._subscriptions = { c: {}, s: [] };
			delete OpenAjax._cleanup;
			OpenAjax._cleanup = [];
			OpenAjax._subIndex = 0;
			OpenAjax._pubDepth = 0;
		}
	};
	// Register the OpenAjax Hub itself as a library.
	OpenAjax.hub.registerLibrary("OpenAjax", "http://openajax.org/hub", "1.0", {});

}