source: [view]
define("dojox/data/ServiceStore", ["dojo", "dojox"], function(dojo, dojox) {
// note that dojox.rpc.Service is not required, you can create your own services
// A ServiceStore is a readonly data store that provides a data.data interface to an RPC service.
// var myServices = new dojox.rpc.Service(dojo.moduleUrl("dojox.rpc.tests.resources", "test.smd"));
// var serviceStore = new dojox.data.ServiceStore({service:myServices.ServiceStore});
//
// The ServiceStore also supports lazy loading. References can be made to objects that have not been loaded.
// For example if a service returned:
// {"name":"Example","lazyLoadedObject":{"$ref":"obj2"}}
//
// And this object has accessed using the dojo.data API:
// var obj = serviceStore.getValue(myObject,"lazyLoadedObject");
// The object would automatically be requested from the server (with an object id of "obj2").
//
dojo.declare("dojox.data.ServiceStore",
// ClientFilter is intentionally not required, ServiceStore does not need it, and is more
// lightweight without it, but if it is provided, the ServiceStore will use it.
dojox.data.ClientFilter||null,{
service: null,
constructor: function(options){
//summary:
// ServiceStore constructor, instantiate a new ServiceStore
// A ServiceStore can be configured from a JSON Schema. Queries are just
// passed through to the underlying services
//
// options:
// Keyword arguments
// The *schema* parameter
// This is a schema object for this store. This should be JSON Schema format.
//
// The *service* parameter
// This is the service object that is used to retrieve lazy data and save results
// The function should be directly callable with a single parameter of an object id to be loaded
//
// The *idAttribute* parameter
// 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.
//
// The *estimateCountFactor* parameter
// This parameter is used by the ServiceStore to estimate the total count. When
// paging is indicated in a fetch and the response includes the full number of items
// requested by the fetch's count parameter, then the total count will be estimated
// to be estimateCountFactor multiplied by the provided count. If this is 1, then it is assumed that the server
// does not support paging, and the response is the full set of items, where the
// total count is equal to the numer of items returned. If the server does support
// paging, an estimateCountFactor of 2 is a good value for estimating the total count
// It is also possible to override _processResults if the server can provide an exact
// total count.
//
// The *syncMode* parameter
// Setting this to true will set the store to using synchronous calls by default.
// Sync calls return their data immediately from the calling function, so
// callbacks are unnecessary. This will only work with a synchronous capable service.
//
// description:
// ServiceStore can do client side caching and result set updating if
// dojox.data.ClientFilter is loaded. Do this add:
// | dojo.require("dojox.data.ClientFilter")
// prior to loading the ServiceStore (ClientFilter must be loaded before ServiceStore).
// To utilize client side filtering with a subclass, you can break queries into
// client side and server side components by putting client side actions in
// clientFilter property in fetch calls. For example you could override fetch:
// | fetch: function(args){
// | // do the sorting and paging on the client side
// | args.clientFilter = {start:args.start, count: args.count, sort: args.sort};
// | // args.query will be passed to the service object for the server side handling
// | return this.inherited(arguments);
// | }
// When extending this class, if you would like to create lazy objects, you can follow
// the example from dojox.data.tests.stores.ServiceStore:
// | var lazyItem = {
// | _loadObject: function(callback){
// | this.name="loaded";
// | delete this._loadObject;
// | callback(this);
// | }
// | };
//setup a byId alias to the api call
this.byId=this.fetchItemByIdentity;
this._index = {};
// if the advanced json parser is enabled, we can pass through object updates as onSet events
if(options){
dojo.mixin(this,options);
}
// We supply a default idAttribute for parser driven construction, but if no id attribute
// is supplied, it should be null so that auto identification takes place properly
this.idAttribute = (options && options.idAttribute) || (this.schema && this.schema._idAttr);
},
schema: null,
idAttribute: "id",
labelAttribute: "label",
syncMode: false,
estimateCountFactor: 1,
getSchema: function(){
return this.schema;
},
loadLazyValues:true,
getValue: function(/*Object*/ item, /*String*/property, /*value?*/defaultValue){
// summary:
// Gets the value of an item's 'property'
//
// item:
// The item to get the value from
// property:
// property to look up value for
// defaultValue:
// the default value
var value = item[property];
return value || // return the plain value since it was found;
(property in item ? // a truthy value was not found, see if we actually have it
value : // we do, so we can return it
item._loadObject ? // property was not found, maybe because the item is not loaded, we will try to load it synchronously so we can get the property
(dojox.rpc._sync = true) && arguments.callee.call(this,dojox.data.ServiceStore.prototype.loadItem({item:item}) || {}, property, defaultValue) : // load the item and run getValue again
defaultValue);// not in item -> return default value
},
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
var val = this.getValue(item,property);
if(val instanceof Array){
return val;
}
if(!this.isItemLoaded(val)){
dojox.rpc._sync = true;
val = this.loadItem({item:val});
}
return val instanceof Array ? val : val === undefined ? [] : [val];
},
getAttributes: function(item){
// summary:
// Gets the available attributes of an item's 'property' and returns
// it as an array.
//
// item: /* object */
var res = [];
for(var i in item){
if(item.hasOwnProperty(i) && !(i.charAt(0) == '_' && i.charAt(1) == '_')){
res.push(i);
}
}
return res;
},
hasAttribute: function(item,attribute){
// summary:
// Checks to see if item has attribute
//
// item: /* object */
// attribute: /* string */
return attribute in item;
},
containsValue: function(item, attribute, value){
// summary:
// Checks to see if 'item' has 'value' at 'attribute'
//
// item: /* object */
// attribute: /* string */
// value: /* anything */
return dojo.indexOf(this.getValues(item,attribute),value) > -1;
},
isItem: function(item){
// summary:
// Checks to see if the argument is an item
//
// item: /* object */
// attribute: /* string */
// we have no way of determining if it belongs, we just have object returned from
// service queries
return (typeof item == 'object') && item && !(item instanceof Date);
},
isItemLoaded: function(item){
// summary:
// Checks to see if the item is loaded.
//
// item: /* object */
return item && !item._loadObject;
},
loadItem: function(args){
// summary:
// Loads an item and calls the callback handler. Note, that this will call the callback
// handler even if the item is loaded. Consequently, you can use loadItem to ensure
// that an item is loaded is situations when the item may or may not be loaded yet.
// If you access a value directly through property access, you can use this to load
// a lazy value as well (doesn't need to be an item).
//
// example:
// store.loadItem({
// item: item, // this item may or may not be loaded
// onItem: function(item){
// // do something with the item
// }
// });
var item;
if(args.item._loadObject){
args.item._loadObject(function(result){
item = result; // in synchronous mode this can allow loadItem to return the value
delete item._loadObject;
var func = result instanceof Error ? args.onError : args.onItem;
if(func){
func.call(args.scope, result);
}
});
}else if(args.onItem){
// even if it is already loaded, we will use call the callback, this makes it easier to
// use when it is not known if the item is loaded (you can always safely call loadItem).
args.onItem.call(args.scope, args.item);
}
return item;
},
_currentId : 0,
_processResults : function(results, deferred){
// this should return an object with the items as an array and the total count of
// items (maybe more than currently in the result set).
// for example:
// | {totalCount:10, items: [{id:1},{id:2}]}
// index the results, assigning ids as necessary
if(results && typeof results == 'object'){
var id = results.__id;
if(!id){// if it hasn't been assigned yet
if(this.idAttribute){
// use the defined id if available
id = results[this.idAttribute];
}else{
id = this._currentId++;
}
if(id !== undefined){
var existingObj = this._index[id];
if(existingObj){
for(var j in existingObj){
delete existingObj[j]; // clear it so we can mixin
}
results = dojo.mixin(existingObj,results);
}
results.__id = id;
this._index[id] = results;
}
}
for(var i in results){
results[i] = this._processResults(results[i], deferred).items;
}
var count = results.length;
}
return {totalCount: deferred.request.count == count ? (deferred.request.start || 0) + count * this.estimateCountFactor : count, items: results};
},
close: function(request){
return request && request.abort && request.abort();
},
fetch: function(args){
// summary:
// See dojo.data.api.Read.fetch
//
// The *queryOptions.cache* parameter
// If true, indicates that the query result should be cached for future use. This is only available
// if dojox.data.ClientFilter has been loaded before the ServiceStore
//
// The *syncMode* parameter
// Indicates that the call should be fetch synchronously if possible (this is not always possible)
//
// The *clientFetch* parameter
// This is a fetch keyword argument for explicitly doing client side filtering, querying, and paging
args = args || {};
if("syncMode" in args ? args.syncMode : this.syncMode){
dojox.rpc._sync = true;
}
var self = this;
var scope = args.scope || self;
var defResult = this.cachingFetch ? this.cachingFetch(args) : this._doQuery(args);
defResult.request = args;
defResult.addCallback(function(results){
if(args.clientFetch){
results = self.clientSideFetch({query:args.clientFetch,sort:args.sort,start:args.start,count:args.count},results);
}
var resultSet = self._processResults(results, defResult);
results = args.results = resultSet.items;
if(args.onBegin){
args.onBegin.call(scope, resultSet.totalCount, args);
}
if(args.onItem){
for(var i=0; i args.onItem.call(scope, results[i], args);
}
}
if(args.onComplete){
args.onComplete.call(scope, args.onItem ? null : results, args);
}
return results;
});
defResult.addErrback(args.onError && function(err){
return args.onError.call(scope, err, args);
});
args.abort = function(){
// abort the request
defResult.cancel();
};
args.store = this;
return args;
},
_doQuery: function(args){
var query= typeof args.queryStr == 'string' ? args.queryStr : args.query;
return this.service(query);
},
getFeatures: function(){
// summary:
// return the store feature set
return {
"dojo.data.api.Read": true,
"dojo.data.api.Identity": true,
"dojo.data.api.Schema": this.schema
};
},
getLabel: function(item){
// summary
// returns the label for an item. Just gets the "label" attribute.
//
return this.getValue(item,this.labelAttribute);