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

dojo.require("dojo.string");

dojo.declare("dojox.data.QueryReadStore",
	null,
	{
		//	summary:
		//		This class provides a store that is mainly intended to be used
		//		for loading data dynamically from the server, used i.e. for
		//		retreiving chunks of data from huge data stores on the server (by server-side filtering!).
		//		Upon calling the fetch() method of this store the data are requested from
		//		the server if they are not yet loaded for paging (or cached).
		//
		//		For example used for a combobox which works on lots of data. It
		//		can be used to retreive the data partially upon entering the
		//		letters "ac" it returns only items like "action", "acting", etc.
		//
		// note:
		//		The field name "id" in a query is reserved for looking up data
		//		by id. This is necessary as before the first fetch, the store
		//		has no way of knowing which field the server will declare as
		//		identifier.
		//
		//	examples:
		// |	// The parameter "query" contains the data that are sent to the server.
		// |	var store = new dojox.data.QueryReadStore({url:'/search.php'});
		// |	store.fetch({query:{name:'a'}, queryOptions:{ignoreCase:false}});
		//
		// |	// Since "serverQuery" is given, it overrules and those data are
		// |	// sent to the server.
		// |	var store = new dojox.data.QueryReadStore({url:'/search.php'});
		// |	store.fetch({serverQuery:{name:'a'}, queryOptions:{ignoreCase:false}});
		//
		// |	<div dojoType="dojox.data.QueryReadStore"
		// |		jsId="store2"
		// |		url="../tests/stores/QueryReadStore.php"
		// |		requestMethod="post"></div>
		// |	<div dojoType="dojox.grid.data.DojoData"
		// |		jsId="model2"
		// |		store="store2"
		// |		sortFields="[{attribute: 'name', descending: true}]"
		// |		rowsPerPage="30"></div>
		// |	<div dojoType="dojox.Grid" id="grid2"
		// |		model="model2"
		// |		structure="gridLayout"
		// |		style="height:300px; width:800px;"></div>
	
		//
		//	todo:
		//		- there is a bug in the paging, when i set start:2, count:5 after an initial fetch() and doClientPaging:true
		//		  it returns 6 elemetns, though count=5, try it in QueryReadStore.html
		//		- add optional caching
		//		- when the first query searched for "a" and the next for a subset of
		//		  the first, i.e. "ab" then we actually dont need a server request, if
		//		  we have client paging, we just need to filter the items we already have
		//		  that might also be tooo much logic
		
		url:"",
		requestMethod:"get",
		//useCache:false,
		
		// We use the name in the errors, once the name is fixed hardcode it, may be.
		_className:"dojox.data.QueryReadStore",
		
		// This will contain the items we have loaded from the server.
		// The contents of this array is optimized to satisfy all read-api requirements
		// and for using lesser storage, so the keys and their content need some explaination:
		// 		this._items[0].i - the item itself 
		//		this._items[0].r - a reference to the store, so we can identify the item
		//			securly. We set this reference right after receiving the item from the
		//			server.
		_items:[],
		
		// Store the last query that triggered xhr request to the server.
		// So we can compare if the request changed and if we shall reload 
		// (this also depends on other factors, such as is caching used, etc).
		_lastServerQuery:null,
		
		
		// Store a hash of the last server request. Actually I introduced this
		// for testing, so I can check if no unnecessary requests were issued for
		// client-side-paging.
		lastRequestHash:null,
		
		// summary:
		//		By default every request for paging is sent to the server.
		doClientPaging:false,
	
		// summary:
		//		By default all the sorting is done serverside before the data is returned
		//		which is the proper place to be doing it for really large datasets.
		doClientSorting:false,
	
		// Items by identify for Identify API
		_itemsByIdentity:null,
		
		// Identifier used
		_identifier:null,
	
		_features: {'dojo.data.api.Read':true, 'dojo.data.api.Identity':true},
	
		_labelAttr: "label",
		
		constructor: function(/* Object */ params){
			dojo.mixin(this,params);
		},
		
		getValue: function(/* item */ item, /* attribute-name-string */ attribute, /* value? */ defaultValue){
			//	According to the Read API comments in getValue() and exception is
			//	thrown when an item is not an item or the attribute not a string!
			this._assertIsItem(item);
			if (!dojo.isString(attribute)) {
				throw new Error(this._className+".getValue(): Invalid attribute, string expected!");
			}
			if(!this.hasAttribute(item, attribute)){
				// read api says: return defaultValue "only if *item* does not have a value for *attribute*." 
				// Is this the case here? The attribute doesn't exist, but a defaultValue, sounds reasonable.
				if(defaultValue){
					return defaultValue;
				}
				console.log(this._className+".getValue(): Item does not have the attribute '"+attribute+"'.");
			}
			return item.i[attribute];
		},
		
		getValues: function(/* item */ item, /* attribute-name-string */ attribute){
			this._assertIsItem(item);
			var ret = [];
			if(this.hasAttribute(item, attribute)){
				ret.push(item.i[attribute]);
			}
			return ret;
		},
		
		getAttributes: function(/* item */ item){
			this._assertIsItem(item);
			var ret = [];
			for(var i in item.i){
				ret.push(i);
			}
			return ret;
		},
	
		hasAttribute: function(/* item */ item,	/* attribute-name-string */ attribute) {
			//	summary: 
			//		See dojo.data.api.Read.hasAttribute()
			return this.isItem(item) && typeof item.i[attribute]!="undefined";
		},
		
		containsValue: function(/* item */ item, /* attribute-name-string */ attribute, /* anything */ value){
			var values = this.getValues(item, attribute);
			var len = values.length;
			for(var i=0; i<len; i++){
				if(values[i]==value){
					return true;
				}
			}
			return false;
		},
		
		isItem: function(/* anything */ something){
			// Some basic tests, that are quick and easy to do here.
			// >>> var store = new dojox.data.QueryReadStore({});
			// >>> store.isItem("");
			// false
			//
			// >>> var store = new dojox.data.QueryReadStore({});
			// >>> store.isItem({});
			// false
			//
			// >>> var store = new dojox.data.QueryReadStore({});
			// >>> store.isItem(0);
			// false
			//
			// >>> var store = new dojox.data.QueryReadStore({});
			// >>> store.isItem({name:"me", label:"me too"});
			// false
			//
			if(something){
				return typeof something.r!="undefined" && something.r==this;
			}
			return false;
		},
		
		isItemLoaded: function(/* anything */ something) {
			// Currently we dont have any state that tells if an item is loaded or not
			// if the item exists its also loaded.
			// This might change when we start working with refs inside items ...
			return this.isItem(something);
		},
	
		loadItem: function(/* object */ args){
			if(this.isItemLoaded(args.item)){
				return;
			}
			// Actually we have nothing to do here, or at least I dont know what to do here ...
		},
	
		fetch:function(/* Object? */ request){
			//	summary:
			//		See dojo.data.util.simpleFetch.fetch() this is just a copy and I adjusted
			//		only the paging, since it happens on the server if doClientPaging is
			//		false, thx to http://trac.dojotoolkit.org/ticket/4761 reporting this.
			//		Would be nice to be able to use simpleFetch() to reduce copied code,
			//		but i dont know how yet. Ideas please!
			request = request || {};
			if(!request.store){
				request.store = this;
			}
			var self = this;
		
			var _errorHandler = function(errorData, requestObject){
				if(requestObject.onError){
					var scope = requestObject.scope || dojo.global;
					requestObject.onError.call(scope, errorData, requestObject);
				}
			};
		
			var _fetchHandler = function(items, requestObject, numRows){
				var oldAbortFunction = requestObject.abort || null;
				var aborted = false;
				
				var startIndex = requestObject.start?requestObject.start:0;
				if (self.doClientPaging==false) {
					// For client paging we dont need no slicing of the result.
					startIndex = 0;
				}
				var endIndex   = requestObject.count?(startIndex + requestObject.count):items.length;
		
				requestObject.abort = function(){
					aborted = true;
					if(oldAbortFunction){
						oldAbortFunction.call(requestObject);
					}
				};
		
				var scope = requestObject.scope || dojo.global;
				if(!requestObject.store){
					requestObject.store = self;
				}
				if(requestObject.onBegin){
					requestObject.onBegin.call(scope, numRows, requestObject);
				}
				if(requestObject.sort && this.doClientSorting){
					items.sort(dojo.data.util.sorter.createSortFunction(requestObject.sort, self));
				}
				if(requestObject.onItem){
					for(var i = startIndex; (i < items.length) && (i < endIndex); ++i){
						var item = items[i];
						if(!aborted){
							requestObject.onItem.call(scope, item, requestObject);
						}
					}
				}