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