source: Dev/trunk/src/client/dojox/mobile/dh/JsonContentHandler.js

define([
        "dojo/_base/kernel",
        "dojo/_base/array",
        "dojo/_base/declare",
        "dojo/_base/lang",
        "dojo/_base/Deferred",
        "dojo/json",
        "dojo/dom-construct"
], function(dojo, array, declare, lang, Deferred, json, domConstruct){

        // module:
        //              dojox/mobile/dh/JsonContentHandler

        return declare("dojox.mobile.dh.JsonContentHandler", null, {
                // summary:
                //              A JSON content handler.
                // description:
                //              This module is a content handler that creates a view from JSON
                //              data. If widgets used in the JSON data are not available, they
                //              are loaded automatically before instantiation.
                //
                //              There are two formats as shown in the examples below. You can
                //              choose either of them. The v1.7 format can be more compact, but
                //              if you want multiple widgets at the same level, they must be in
                //              an array. So, you can have, for example, two consecutive
                //              RoundRectLists, but you cannot have, for example,
                //              RoundRectCategory, RoundRectList, RoundRectCategory, and
                //              RoundRectList, because they are keys in one JS object, which
                //              causes conflict. The v1.8 format has no such limitation.
                //
                // example:
                //      |       // v1.7 format
                //      |       {
                //      |         "dojox.mobile.View": {
                //      |           "@id": "view1",
                //      |           "dojox.mobile.Heading": {
                //      |             "@back": "Home",
                //      |             "@moveTo": "home",
                //      |             "@label": "view1.json"
                //      |           },
                //      |           "dojox.mobile.EdgeToEdgeList": {
                //      |             "dojox.mobile.ListItem": [{
                //      |               "@label": "Jack Coleman"
                //      |             }, {
                //      |               "@label": "James Evans"
                //      |             }, {
                //      |               "@label": "Jason Griffin"
                //      |             }]
                //      |           }
                //      |         }
                //      |       }
                //      |       
                // example:
                //      |       // v1.8 format
                //      |       {
                //      |         "class": "dojox.mobile.View",
                //      |         "@id": "view1",
                //      |         "children": [
                //      |       
                //      |           {
                //      |             "class": "dojox.mobile.Heading",
                //      |             "@back": "Home",
                //      |             "@moveTo": "home",
                //      |             "@label": "view1.json"
                //      |           },
                //      |       
                //      |           {
                //      |             "class": "dojox.mobile.EdgeToEdgeList",
                //      |             "children": [
                //      |               {
                //      |                 "class": "dojox.mobile.ListItem",
                //      |                 "@label": "Jack Coleman"
                //      |               },
                //      |               {
                //      |                 "class": "dojox.mobile.ListItem",
                //      |                 "@label": "James Evans"
                //      |               },
                //      |               {
                //      |                 "class": "dojox.mobile.ListItem",
                //      |                 "@label": "Jason Griffin"
                //      |               }
                //      |             ]
                //      |           }
                //      |       
                //      |         ]
                //      |       }
                //      |       
                // example:
                //      |       // SpinWheel in v1.8 format
                //      |       {
                //      |         "class": "dojox.mobile.View",
                //      |         "@id": "view1",
                //      |         "children": [
                //      |           {
                //      |             "class": "dojox.mobile.SpinWheel",
                //      |             "@id": "spin1",
                //      |             "@style": {"margin":"10px auto","width":"304px"},
                //      |             "children": [
                //      |               {
                //      |                 "class": "dojox.mobile.SpinWheelSlot",
                //      |                 "@labels": "A,B,C,D,E",
                //      |                 "@style": {"textAlign":"center","width":"300px"}
                //      |               }
                //      |             ]
                //      |           }
                //      |         ]
                //      |       }

                parse: function(/*Object*/ content, /*DomNode*/ target, /*DomNode?*/ refNode){
                        // summary:
                        //              Parses the given data and creates a new view at the given position.
                        // content:
                        //              Content data for a new view.
                        // target:
                        //              A DOM node under which a new view is created.
                        // refNode:
                        //              An optional reference DOM node before which a new view is created.
                        var view, container = domConstruct.create("DIV");
                        target.insertBefore(container, refNode);
                        this._ws = [];
                        this._req = [];
                        var root = json.parse(content);
                        return Deferred.when(this._loadPrereqs(root), lang.hitch(this, function(){
                                view = this._instantiate(root, container);
                                view.style.visibility = "hidden";
                                array.forEach(this._ws, function(w){
                                        if(!w._started && w.startup){
                                                w.startup();
                                        }
                                });
                                this._ws = null;
                                return view.id;
                        }));
                },

                _loadPrereqs: function(root){
                        // tags:
                        //              private
                        var d = new Deferred();
                        var req = this._collectRequires(root);
                        if(req.length === 0){ return true; }

                        if(dojo.require){
                                array.forEach(req, function(c){
                                        dojo["require"](c);
                                });
                                return true;
                        }else{
                                req = array.map(req, function(s){ return s.replace(/\./g, "/"); });
                                require(req, function(){
                                        d.resolve(true);
                                });
                        }
                        return d;
                },

                _collectRequires: function(obj){
                        // tags:
                        //              private
                        var className = obj["class"];
                        for(var key in obj){
                                if(key.charAt(0) == "@" || key === "children"){ continue; }
                                var cls = className || key.replace(/:.*/, "");
                                this._req.push(cls);
                                if(!cls){ continue; }
                                var objs = className ? [obj] :
                                                (lang.isArray(obj[key]) ? obj[key] : [obj[key]]);
                                for(var i = 0; i < objs.length; i++){
                                        // process child widgets
                                        if(!className){
                                                this._collectRequires(objs[i]);
                                        }else if(objs[i].children){
                                                for(var j = 0; j < objs[i].children.length; j++){
                                                        this._collectRequires(objs[i].children[j]);
                                                }
                                        }
                                }
                        }
                        return this._req;
                },

                _instantiate: function(/*Object*/obj, /*DomNode*/node, /*Widget*/parent){
                        // summary:
                        //              Given the evaluated json data, does the same thing as what
                        //              the parser does.
                        // tags:
                        //              private
                        var widget;
                        var className = obj["class"];
                        for(var key in obj){
                                if(key.charAt(0) == "@" || key === "children"){ continue; }
                                var cls = lang.getObject(className || key.replace(/:.*/, ""));
                                if(!cls){ continue; }
                                var proto = cls.prototype,
                                        objs = className ? [obj] :
                                                (lang.isArray(obj[key]) ? obj[key] : [obj[key]]);
                                for(var i = 0; i < objs.length; i++){
                                        var params = {};
                                        for(var prop in objs[i]){
                                                if(prop.charAt(0) == "@"){
                                                        var v = objs[i][prop];
                                                        prop = prop.substring(1);
                                                        var t = typeof proto[prop];
                                                        if(lang.isArray(proto[prop])){
                                                                params[prop] = v.split(/\s*,\s*/);
                                                        }else if(t === "string"){
                                                                params[prop] = v;
                                                        }else if(t === "number"){
                                                                params[prop] = v - 0;
                                                        }else if(t === "boolean"){
                                                                params[prop] = (v !== "false");
                                                        }else if(t === "object"){
                                                                params[prop] = json.parse(v);
                                                        }else if(t === "function"){
                                                                params[prop] = lang.getObject(v, false) || new Function(v);
                                                        }
                                                }
                                        }
                                        widget = new cls(params, node);
                                        if(node){ // to call View's startup()
                                                this._ws.push(widget);
                                        }
                                        if(parent){
                                                widget.placeAt(parent.containerNode || parent.domNode);
                                        }
                                        // process child widgets
                                        if(!className){
                                                this._instantiate(objs[i], null, widget);
                                        }else if(objs[i].children){
                                                for(var j = 0; j < objs[i].children.length; j++){
                                                        this._instantiate(objs[i].children[j], null, widget);
                                                }
                                        }
                                }
                        }
                        return widget && widget.domNode;
                }
        });
});