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 2006-2007 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(){
		// summary:
		//		the OpenAjax hub
		// description:
		//		see http://www.openajax.org/member/wiki/OpenAjax_Hub_Specification

		var libs = {};
		var ooh = "org.openajax.hub.";

		var h = {};
		this.hub = h;
		h.implementer = "http://openajax.org";
		h.implVersion = "0.6";
		h.specVersion = "0.6";
		h.implExtraData = {};
		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);
			}
		};

		h._publish = function(tree, path, index, name, msg){
			if(typeof tree != "undefined"){
				var node;
				if(index == path.length){
					node = tree;
				}else{
					this._publish(tree.c[path[index]], path, index + 1, name, msg);
					this._publish(tree.c["*"], path, index + 1, name, msg);
					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);
							}
						}
					}
				}
			}
		};
			
		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", "0.6", {});

			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", "0.6", {});

}