jsonpathstore.js

这是一个ajax的例子大家好好的看看就是一个鱼眼的效果

if(!dojo._hasResource["dojox.data.jsonPathStore"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojox.data.jsonPathStore"] = true;
dojo.provide("dojox.data.jsonPathStore");
dojo.require("dojox.jsonPath");
dojo.require("dojo.date");
dojo.require("dojo.date.locale");
dojo.require("dojo.date.stamp");

dojox.data.ASYNC_MODE = 0;
dojox.data.SYNC_MODE = 1;

dojo.declare("dojox.data.jsonPathStore",
	null,
	{
		mode: dojox.data.ASYNC_MODE,
		metaLabel: "_meta",
		hideMetaAttributes: false,
		autoIdPrefix: "_auto_",
		autoIdentity: true,
		idAttribute: "_id",
		indexOnLoad: true,
		labelAttribute: "",
		url: "",
		_replaceRegex: /\'\]/gi,
		
		constructor: function(options){
			//summary:
			//	jsonPathStore constructor, instantiate a new jsonPathStore 
			//
			//	Takes a single optional parameter in the form of a Javascript object
			//	containing one or more of the following properties. 
			//
			//	data: /*JSON String*/ || /* Javascript Object */, 
			//		JSON String or Javascript object this store will control
			//		JSON is converted into an object, and an object passed to
			//		the store will be used directly.  If no data and no url
			//		is provide, an empty object, {}, will be used as the initial
			//		store.
			//
			//	url: /* string url */ 	
			//		Load data from this url in JSON format and use the Object
			//		created from the data as the data source.
			//
			//	indexOnLoad: /* boolean */ 
			//		Defaults to true, but this may change in the near future.
			//		Parse the data object and set individual objects up as
			//		appropriate.  This will add meta data and assign
			//		id's to objects that dont' have them as defined by the
			//		idAttribute option.  Disabling this option will keep this 
			//		parsing from happening until a query is performed at which
			//		time only the top level of an item has meta info stored.
			//		This might work in some situations, but you will almost
			//		always want to indexOnLoad or use another option which
			//		will create an index.  In the future we will support a 
			//		generated index that maps by jsonPath allowing the
			//		server to take some of this load for larger data sets. 
			//
			//	idAttribute: /* string */
			//		Defaults to '_id'. The name of the attribute that holds an objects id.
			//		This can be a preexisting id provided by the server.  
			//		If an ID isn't already provided when an object
			//		is fetched or added to the store, the autoIdentity system
			//		will generate an id for it and add it to the index. There
			//		are utility routines for exporting data from the store
			//		that can clean any generated IDs before exporting and leave
			//		preexisting id's in tact.
			//
			//	metaLabel: /* string */
			//		Defaults to '_meta' overrides the attribute name that is used by the store
			//		for attaching meta information to an object while
			//		in the store's control.  Defaults to '_meta'. 
			//	
			//	hideMetaAttributes: /* boolean */
			//		Defaults to False.  When enabled, calls to getAttributes() will not 
			//		include the meta attribute.
			//
			//	autoIdPrefix: /*string*/
			//		Defaults to "_auto_".  This string is used as the prefix to any
			//		objects which have a generated id. A numeric index is appended
			//		to this string to complete the ID
			//
			//	mode: dojox.data.ASYNC_MODE || dojox.data.SYNC_MODE
			//		Defaults to ASYNC_MODE.  This option sets the default mode for this store.
			//		Sync calls return their data immediately from the calling function
			//		instead of calling the callback functions.  Functions such as 
			//		fetchItemByIdentity() and fetch() both accept a string parameter in addtion
			//		to the normal keywordArgs parameter.  When passed this option, SYNC_MODE will
			//		automatically be used even when the default mode of the system is ASYNC_MODE.
			//		A normal request to fetch or fetchItemByIdentity (with kwArgs object) can also 
			//		include a mode property to override this setting for that one request.

			//setup a byId alias to the api call	
			this.byId=this.fetchItemByIdentity;

			if (options){
				dojo.mixin(this,options);
			}

			this._dirtyItems=[];
			this._autoId=0;
			this._referenceId=0;
			this._references={};
			this._fetchQueue=[];
			this.index={};

			//regex to identify when we're travelling down metaObject (which we don't want to do) 
			var expr="("+this.metaLabel+"\'\])";
			this.metaRegex = new RegExp(expr);


			//no data or url, start with an empty object for a store
			if (!this.data && !this.url){
				this.setData({});
			}	

			//we have data, but no url, set the store as the data
			if (this.data && !this.url){
				this.setData(this.data);

				//remove the original refernce, we're now using _data from here on out
				delete this.data;
			}

			//given a url, load json data from as the store
			if (this.url){
				dojo.xhrGet({
					url: options.url,
					handleAs: "json",
					load: dojo.hitch(this, "setData"),
					sync: this.mode
				});
			}
		},

		_loadData: function(data){
			// summary:
			//	load data into the store. Index it if appropriate.
			if (this._data){
				delete this._data;
			}

			if (dojo.isString(data)){
				this._data = dojo.fromJson(data);
			}else{
				this._data = data;
			}
			
			if (this.indexOnLoad){
				this.buildIndex();		
			}	

			this._updateMeta(this._data, {path: "$"});

			this.onLoadData(this._data);
		},

		onLoadData: function(data){
			// summary
			//	Called after data has been loaded in the store.  
			//	If any requests happened while the startup is happening
			//	then process them now.

			while (this._fetchQueue.length>0){
				var req = this._fetchQueue.shift();
				this.fetch(req);
			}	

		},

		setData: function(data){
			// summary:
			//	set the stores' data to the supplied object and then 
			//	load and/or setup that data with the required meta info		
			this._loadData(data);
		},

		buildIndex: function(path, item){
			//summary: 
			//	parse the object structure, and turn any objects into
			//	jsonPathStore items. Basically this just does a recursive
			//	series of fetches which itself already examines any items
			//	as they are retrieved and setups up the required meta information. 
			//
			//	path: /* string */
			//		jsonPath Query for the starting point of this index construction.

			if (!this.idAttribute){
				throw new Error("buildIndex requires idAttribute for the store");
			}

			item = item || this._data;
			var origPath = path;
			path = path||"$";
			path += "[*]";
			var data = this.fetch({query: path,mode: dojox.data.SYNC_MODE});
			for(var i=0; i<data.length;i++){
				if(dojo.isObject(data[i])){
					var newPath = data[i][this.metaLabel]["path"];
					if (origPath){
						//console.log("newPath: ", newPath);
						//console.log("origPath: ", origPath);
						//console.log("path: ", path);
						//console.log("data[i]: ", data[i]);
						var parts = origPath.split("\[\'");
						var attribute = parts[parts.length-1].replace(this._replaceRegex,'');
						//console.log("attribute: ", attribute);
						//console.log("ParentItem: ", item, attribute);
						if (!dojo.isArray(data[i])){
							this._addReference(data[i], {parent: item, attribute:attribute});
							this.buildIndex(newPath, data[i]);
						}else{
							this.buildIndex(newPath,item);
						}
					}else{
						var parts = newPath.split("\[\'");
						var attribute = parts[parts.length-1].replace(this._replaceRegex,'');
						this._addReference(data[i], {parent: this._data, attribute:attribute});
						this.buildIndex(newPath, data[i]);
					}
				}
			}
		},

		_correctReference: function(item){
			// summary:
			//	make sure we have an reference to the item in the store
			//	and not a clone. Takes an item, matches it to the corresponding
			//	item in the store and if it is the same, returns itself, otherwise
			//	it returns the item from the store.
		
			if (this.index[item[this.idAttribute]][this.metaLabel]===item[this.metaLabel]){
				return this.index[item[this.idAttribute]];
			}
			return item;	
		},

		getValue: function(item, property){
			// summary:
			//	Gets the value of an item's 'property'
			//
			//	item: /* object */
			//	property: /* string */
			//		property to look up value for	
			item = this._correctReference(item);
			return item[property];
		},

		getValues: function(item, property){
			// summary:
			//	Gets the value of an item's 'property' and returns
			//	it.  If this value is an array it is just returned,
			//	if not, the value is added to an array and that is returned.
			//
			//	item: /* object */
			//	property: /* string */
			//		property to look up value for	
	
			item = this._correctReference(item);
			return dojo.isArray(item[property]) ? item[property] : [item[property]];
		},

		getAttributes: function(item){
			// summary:
			//	Gets the available attributes of an item's 'property' and returns
			//	it as an array. If the store has 'hideMetaAttributes' set to true
			//	the attributed identified by 'metaLabel' will not be included.
			//
			//	item: /* object */

			item = this._correctReference(item);
			var res = [];
			for (var i in item){
				if (this.hideMetaAttributes && (i==this.metaLabel)){continue;}
				res.push(i);
			}
			return res;
		},

		hasAttribute: function(item,attribute){
			// summary:
			//	Checks to see if item has attribute
			//
			//	item: /* object */
			//	attribute: /* string */
		
			item = this._correctReference(item);
			if (attribute in item){return true;}
			return false;	
		},

		containsValue: function(item, attribute, value){
			// summary:
			//	Checks to see if 'item' has 'value' at 'attribute'
			//
			//	item: /* object */
			//	attribute: /* string */
			//	value: /* anything */
			item = this._correctReference(item);

			if (item[attribute] && item[attribute]==value){return true}
			if (dojo.isObject(item[attribute]) || dojo.isObject(value)){
				if (this._shallowCompare(item[attribute],value)){return true}
			}
			return false;	
		},

		_shallowCompare: function(a, b){
			//summary does a simple/shallow compare of properties on an object
			//to the same named properties on the given item. Returns
			//true if all props match. It will not descend into child objects
			//but it will compare child date objects

			if ((dojo.isObject(a) && !dojo.isObject(b))|| (dojo.isObject(b) && !dojo.isObject(a))) {
				return false;
			}

			if ( a["getFullYear"] || b["getFullYear"] ){
				//confirm that both are dates
				if ( (a["getFullYear"] && !b["getFullYear"]) || (b["getFullYear"] && !a["getFullYear"]) ){
					return false;
				}else{
					if (!dojo.date.compare(a,b)){
						return true;
					}
					return false;
       				}
			}

			for (var i in b){	
				if (dojo.isObject(b[i])){
					if (!a[i] || !dojo.isObject(a[i])){return false}

					if (b[i]["getFullYear"]){
						if(!a[i]["getFullYear"]){return false}
						if (dojo.date.compare(a,b)){return false}	
					}else{
						if (!this._shallowCompare(a[i],b[i])){return false}
					}
				}else{	
					if (!b[i] || (a[i]!=b[i])){return false}
				}
			}

			//make sure there werent props on a that aren't on b, if there aren't, then
			//the previous section will have already evaluated things.

			for (var i in a){
				if (!b[i]){return false}
			}
			
			return true;
		},

		isItem: function(item){
			// summary:
			//	Checks to see if a passed 'item'
			//	is really a jsonPathStore item.  Currently
			//	it only verifies structure.  It does not verify
			//	that it belongs to this store at this time.
			//
			//	item: /* object */
			//	attribute: /* string */
		
			if (!dojo.isObject(item) || !item[this.metaLabel]){return false}
			if (this.requireId && this._hasId && !item[this._id]){return false}
			return true;
		},

		isItemLoaded: function(item){
			// summary:
			//	returns isItem() :)
			//
			//	item: /* object */

			item = this._correctReference(item);
			return this.isItem(item);
		},

		loadItem: function(item){
			// summary:
			//	returns true. Future implementatins might alter this 
			return true;
		},

		_updateMeta: function(item, props){
			// summary:
			//	verifies that 'item' has a meta object attached
			//	and if not it creates it by setting it to 'props'
			//	if the meta attribute already exists, mix 'props'
			//	into it.

			if (item && item[this.metaLabel]){
				dojo.mixin(item[this.metaLabel], props);
				return;
			}

			item[this.metaLabel]=props;
		},