itemfilereadstore.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["dojo.data.ItemFileReadStore"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo.data.ItemFileReadStore"] = true;
dojo.provide("dojo.data.ItemFileReadStore");

dojo.require("dojo.data.util.filter");
dojo.require("dojo.data.util.simpleFetch");
dojo.require("dojo.date.stamp");

dojo.declare("dojo.data.ItemFileReadStore", null,{
	//	summary:
	//		The ItemFileReadStore implements the dojo.data.api.Read API and reads
	//		data from JSON files that have contents in this format --
	//		{ items: [
	//			{ name:'Kermit', color:'green', age:12, friends:['Gonzo', {_reference:{name:'Fozzie Bear'}}]},
	//			{ name:'Fozzie Bear', wears:['hat', 'tie']},
	//			{ name:'Miss Piggy', pets:'Foo-Foo'}
	//		]}
	//		Note that it can also contain an 'identifer' property that specified which attribute on the items 
	//		in the array of items that acts as the unique identifier for that item.
	//
	constructor: function(/* Object */ keywordParameters){
		//	summary: constructor
		//	keywordParameters: {url: String}
		//	keywordParameters: {data: jsonObject}
		//	keywordParameters: {typeMap: object)
		//		The structure of the typeMap object is as follows:
		//		{
		//			type0: function || object,
		//			type1: function || object,
		//			...
		//			typeN: function || object
		//		}
		//		Where if it is a function, it is assumed to be an object constructor that takes the 
		//		value of _value as the initialization parameters.  If it is an object, then it is assumed
		//		to be an object of general form:
		//		{
		//			type: function, //constructor.
		//			deserialize:	function(value) //The function that parses the value and constructs the object defined by type appropriately.
		//		}
	
		this._arrayOfAllItems = [];
		this._arrayOfTopLevelItems = [];
		this._loadFinished = false;
		this._jsonFileUrl = keywordParameters.url;
		this._jsonData = keywordParameters.data;
		this._datatypeMap = keywordParameters.typeMap || {};
		if(!this._datatypeMap['Date']){
			//If no default mapping for dates, then set this as default.
			//We use the dojo.date.stamp here because the ISO format is the 'dojo way'
			//of generically representing dates.
			this._datatypeMap['Date'] = {
											type: Date,
											deserialize: function(value){
												return dojo.date.stamp.fromISOString(value);
											}
										};
		}
		this._features = {'dojo.data.api.Read':true, 'dojo.data.api.Identity':true};
		this._itemsByIdentity = null;
		this._storeRefPropName = "_S";  // Default name for the store reference to attach to every item.
		this._itemNumPropName = "_0"; // Default Item Id for isItem to attach to every item.
		this._rootItemPropName = "_RI"; // Default Item Id for isItem to attach to every item.
		this._reverseRefMap = "_RRM"; // Default attribute for constructing a reverse reference map for use with reference integrity
		this._loadInProgress = false;	//Got to track the initial load to prevent duelling loads of the dataset.
		this._queuedFetches = [];
	},
	
	url: "",	// use "" rather than undefined for the benefit of the parser (#3539)

	_assertIsItem: function(/* item */ item){
		//	summary:
		//		This function tests whether the item passed in is indeed an item in the store.
		//	item: 
		//		The item to test for being contained by the store.
		if(!this.isItem(item)){ 
			throw new Error("dojo.data.ItemFileReadStore: Invalid item argument.");
		}
	},

	_assertIsAttribute: function(/* attribute-name-string */ attribute){
		//	summary:
		//		This function tests whether the item passed in is indeed a valid 'attribute' like type for the store.
		//	attribute: 
		//		The attribute to test for being contained by the store.
		if(typeof attribute !== "string"){ 
			throw new Error("dojo.data.ItemFileReadStore: Invalid attribute argument.");
		}
	},

	getValue: function(	/* item */ item, 
						/* attribute-name-string */ attribute, 
						/* value? */ defaultValue){
		//	summary: 
		//		See dojo.data.api.Read.getValue()
		var values = this.getValues(item, attribute);
		return (values.length > 0)?values[0]:defaultValue; // mixed
	},

	getValues: function(/* item */ item, 
						/* attribute-name-string */ attribute){
		//	summary: 
		//		See dojo.data.api.Read.getValues()

		this._assertIsItem(item);
		this._assertIsAttribute(attribute);
		return item[attribute] || []; // Array
	},

	getAttributes: function(/* item */ item){
		//	summary: 
		//		See dojo.data.api.Read.getAttributes()
		this._assertIsItem(item);
		var attributes = [];
		for(var key in item){
			// Save off only the real item attributes, not the special id marks for O(1) isItem.
			if((key !== this._storeRefPropName) && (key !== this._itemNumPropName) && (key !== this._rootItemPropName) && (key !== this._reverseRefMap)){
				attributes.push(key);
			}
		}
		return attributes; // Array
	},

	hasAttribute: function(	/* item */ item,
							/* attribute-name-string */ attribute) {
		//	summary: 
		//		See dojo.data.api.Read.hasAttribute()
		return this.getValues(item, attribute).length > 0;
	},

	containsValue: function(/* item */ item, 
							/* attribute-name-string */ attribute, 
							/* anything */ value){
		//	summary: 
		//		See dojo.data.api.Read.containsValue()
		var regexp = undefined;
		if(typeof value === "string"){
			regexp = dojo.data.util.filter.patternToRegExp(value, false);
		}
		return this._containsValue(item, attribute, value, regexp); //boolean.
	},

	_containsValue: function(	/* item */ item, 
								/* attribute-name-string */ attribute, 
								/* anything */ value,
								/* RegExp?*/ regexp){
		//	summary: 
		//		Internal function for looking at the values contained by the item.
		//	description: 
		//		Internal function for looking at the values contained by the item.  This 
		//		function allows for denoting if the comparison should be case sensitive for
		//		strings or not (for handling filtering cases where string case should not matter)
		//	
		//	item:
		//		The data item to examine for attribute values.
		//	attribute:
		//		The attribute to inspect.
		//	value:	
		//		The value to match.
		//	regexp:
		//		Optional regular expression generated off value if value was of string type to handle wildcarding.
		//		If present and attribute values are string, then it can be used for comparison instead of 'value'
		return dojo.some(this.getValues(item, attribute), function(possibleValue){
			if(possibleValue !== null && !dojo.isObject(possibleValue) && regexp){
				if(possibleValue.toString().match(regexp)){
					return true; // Boolean
				}
			}else if(value === possibleValue){
				return true; // Boolean
			}
		});
	},

	isItem: function(/* anything */ something){
		//	summary: 
		//		See dojo.data.api.Read.isItem()
		if(something && something[this._storeRefPropName] === this){
			if(this._arrayOfAllItems[something[this._itemNumPropName]] === something){
				return true;
			}
		}
		return false; // Boolean
	},

	isItemLoaded: function(/* anything */ something){
		//	summary: 
		//		See dojo.data.api.Read.isItemLoaded()
		return this.isItem(something); //boolean
	},

	loadItem: function(/* object */ keywordArgs){
		//	summary: 
		//		See dojo.data.api.Read.loadItem()
		this._assertIsItem(keywordArgs.item);
	},

	getFeatures: function(){
		//	summary: 
		//		See dojo.data.api.Read.getFeatures()
		return this._features; //Object
	},

	getLabel: function(/* item */ item){
		//	summary: 
		//		See dojo.data.api.Read.getLabel()
		if(this._labelAttr && this.isItem(item)){
			return this.getValue(item,this._labelAttr); //String
		}
		return undefined; //undefined
	},

	getLabelAttributes: function(/* item */ item){
		//	summary: 
		//		See dojo.data.api.Read.getLabelAttributes()
		if(this._labelAttr){
			return [this._labelAttr]; //array
		}
		return null; //null
	},

	_fetchItems: function(	/* Object */ keywordArgs, 
							/* Function */ findCallback, 
							/* Function */ errorCallback){
		//	summary: 
		//		See dojo.data.util.simpleFetch.fetch()
		var self = this;
		var filter = function(requestArgs, arrayOfItems){
			var items = [];
			if(requestArgs.query){
				var ignoreCase = requestArgs.queryOptions ? requestArgs.queryOptions.ignoreCase : false; 

				//See if there are any string values that can be regexp parsed first to avoid multiple regexp gens on the
				//same value for each item examined.  Much more efficient.
				var regexpList = {};
				for(var key in requestArgs.query){
					var value = requestArgs.query[key];
					if(typeof value === "string"){
						regexpList[key] = dojo.data.util.filter.patternToRegExp(value, ignoreCase);
					}
				}

				for(var i = 0; i < arrayOfItems.length; ++i){
					var match = true;
					var candidateItem = arrayOfItems[i];
					if(candidateItem === null){
						match = false;
					}else{
						for(var key in requestArgs.query) {
							var value = requestArgs.query[key];
							if (!self._containsValue(candidateItem, key, value, regexpList[key])){
								match = false;
							}
						}
					}
					if(match){
						items.push(candidateItem);
					}
				}
				findCallback(items, requestArgs);
			}else{
				// We want a copy to pass back in case the parent wishes to sort the array. 
				// We shouldn't allow resort of the internal list, so that multiple callers 
				// can get lists and sort without affecting each other.  We also need to
				// filter out any null values that have been left as a result of deleteItem()
				// calls in ItemFileWriteStore.
				for(var i = 0; i < arrayOfItems.length; ++i){
					var item = arrayOfItems[i];
					if(item !== null){
						items.push(item);
					}
				}
				findCallback(items, requestArgs);
			}
		};

		if(this._loadFinished){
			filter(keywordArgs, this._getItemsArray(keywordArgs.queryOptions));
		}else{

			if(this._jsonFileUrl){
				//If fetches come in before the loading has finished, but while
				//a load is in progress, we have to defer the fetching to be 
				//invoked in the callback.
				if(this._loadInProgress){
					this._queuedFetches.push({args: keywordArgs, filter: filter});
				}else{
					this._loadInProgress = true;
					var getArgs = {
							url: self._jsonFileUrl, 
							handleAs: "json-comment-optional"
						};
					var getHandler = dojo.xhrGet(getArgs);
					getHandler.addCallback(function(data){
						try{
							self._getItemsFromLoadedData(data);
							self._loadFinished = true;
							self._loadInProgress = false;
							
							filter(keywordArgs, self._getItemsArray(keywordArgs.queryOptions));
							self._handleQueuedFetches();
						}catch(e){
							self._loadFinished = true;
							self._loadInProgress = false;
							errorCallback(e, keywordArgs);
						}
					});
					getHandler.addErrback(function(error){
						self._loadInProgress = false;
						errorCallback(error, keywordArgs);
					});
				}
			}else if(this._jsonData){
				try{
					this._loadFinished = true;
					this._getItemsFromLoadedData(this._jsonData);
					this._jsonData = null;
					filter(keywordArgs, this._getItemsArray(keywordArgs.queryOptions));
				}catch(e){
					errorCallback(e, keywordArgs);
				}
			}else{
				errorCallback(new Error("dojo.data.ItemFileReadStore: No JSON source data was provided as either URL or a nested Javascript object."), keywordArgs);
			}
		}
	},

	_handleQueuedFetches: function(){
		//	summary: 
		//		Internal function to execute delayed request in the store.
		//Execute any deferred fetches now.
		if (this._queuedFetches.length > 0) {
			for(var i = 0; i < this._queuedFetches.length; i++){
				var fData = this._queuedFetches[i];
				var delayedQuery = fData.args;
				var delayedFilter = fData.filter;
				if(delayedFilter){
					delayedFilter(delayedQuery, this._getItemsArray(delayedQuery.queryOptions)); 
				}else{
					this.fetchItemByIdentity(delayedQuery);
				}
			}
			this._queuedFetches = [];
		}
	},

	_getItemsArray: function(/*object?*/queryOptions){
		//	summary: 
		//		Internal function to determine which list of items to search over.
		//	queryOptions: The query options parameter, if any.
		if(queryOptions && queryOptions.deep) {
			return this._arrayOfAllItems; 
		}
		return this._arrayOfTopLevelItems;
	},

	close: function(/*dojo.data.api.Request || keywordArgs || null */ request){
		 //	summary: 
		 //		See dojo.data.api.Read.close()
	},

	_getItemsFromLoadedData: function(/* Object */ dataObject){
		//	summary:
		//		Function to parse the loaded data into item format and build the internal items array.
		//	description:
		//		Function to parse the loaded data into item format and build the internal items array.
		//
		//	dataObject:
		//		The JS data object containing the raw data to convery into item format.
		//
		// 	returns: array
		//		Array of items in store item format.
		
		// First, we define a couple little utility functions...
		
		function valueIsAnItem(/* anything */ aValue){
			// summary:
			//		Given any sort of value that could be in the raw json data,
			//		return true if we should interpret the value as being an
			//		item itself, rather than a literal value or a reference.
			// example:
			// 	|	false == valueIsAnItem("Kermit");
			// 	|	false == valueIsAnItem(42);
			// 	|	false == valueIsAnItem(new Date());
			// 	|	false == valueIsAnItem({_type:'Date', _value:'May 14, 1802'});