lib/dojo/store/DataStore.js

   1 /*
   2         Copyright (c) 2004-2011, The Dojo Foundation All Rights Reserved.
   3         Available via Academic Free License >= 2.1 OR the modified BSD license.
   4         see: http://dojotoolkit.org/license for details
   5 */
   6
   7
   8 if(!dojo._hasResource["dojo.store.DataStore"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
   9 dojo._hasResource["dojo.store.DataStore"] = true;
  10 dojo.provide("dojo.store.DataStore");
  11 dojo.require("dojo.store.util.QueryResults");
  12
  13
  14 dojo.declare("dojo.store.DataStore", null, {
  15         target: "",
  16         constructor: function(options){
  17                 // summary:
  18                 //              This is an adapter for using Dojo Data stores with an object store consumer.
  19                 //              You can provide a Dojo data store and use this adapter to interact with it through
  20                 //              the Dojo object store API
  21                 // options: Object?
  22                 //              This provides any configuration information that will be mixed into the store,
  23                 //              including a reference to the Dojo data store under the property "store".
  24                 dojo.mixin(this, options);
  25         },
  26         _objectConverter: function(callback){
  27                 var store = this.store;
  28                 return function(item){
  29                         var object = {};
  30                         var attributes = store.getAttributes(item);
  31                         for(var i = 0; i < attributes.length; i++){
  32                                 object[attributes[i]] = store.getValue(item, attributes[i]);
  33                         }
  34                         return callback(object);
  35                 };
  36         },
  37         get: function(id, options){
  38                 // summary:
  39                 //              Retrieves an object by it's identity. This will trigger a fetchItemByIdentity
  40                 // id: Object?
  41                 //              The identity to use to lookup the object
  42                 var returnedObject, returnedError;
  43                 var deferred = new dojo.Deferred();
  44                 this.store.fetchItemByIdentity({
  45                         identity: id,
  46                         onItem: this._objectConverter(function(object){
  47                                 deferred.resolve(returnedObject = object);
  48                         }),
  49                         onError: function(error){
  50                                 deferred.reject(returnedError = error);
  51                         }
  52                 });
  53                 if(returnedObject){
  54                         // if it was returned synchronously
  55                         return returnedObject;
  56                 }
  57                 if(returnedError){
  58                         throw returnedError;
  59                 }
  60                 return deferred.promise;
  61         },
  62         put: function(object, options){
  63                 // summary:
  64                 //              Stores an object by its identity.
  65                 // object: Object
  66                 //              The object to store.
  67                 // options: Object?
  68                 //              Additional metadata for storing the data.  Includes a reference to an id
  69                 //              that the object may be stored with (i.e. { id: "foo" }).
  70                 var id = options && typeof options.id != "undefined" || this.getIdentity(object);
  71                 var store = this.store;
  72                 if(typeof id == "undefined"){
  73                         store.newItem(object);
  74                 }else{
  75                         store.fetchItemByIdentity({
  76                                 identity: id,
  77                                 onItem: function(item){
  78                                         if(item){
  79                                                 for(var i in object){
  80                                                         if(store.getValue(item, i) != object[i]){
  81                                                                 store.setValue(item, i, object[i]);
  82                                                         }
  83                                                 }
  84                                         }else{
  85                                                 store.newItem(object);
  86                                         }
  87                                 }
  88                         });
  89                 }
  90         },
  91         remove: function(id){
  92                 // summary:
  93                 //              Deletes an object by its identity.
  94                 // id: Object
  95                 //              The identity to use to delete the object
  96                 var store = this.store;
  97                 this.store.fetchItemByIdentity({
  98                         identity: id,
  99                         onItem: function(item){
 100                                 store.deleteItem(item);
 101                         }
 102                 });
 103         },
 104         query: function(query, options){
 105                 // summary:
 106                 //              Queries the store for objects.
 107                 // query: Object
 108                 //              The query to use for retrieving objects from the store
 109                 // options: Object?
 110                 //              Optional options object as used by the underlying dojo.data Store.
 111                 // returns: dojo.store.util.QueryResults
 112                 //              A query results object that can be used to iterate over results.
 113                 var returnedObject, returnedError;
 114                 var deferred = new dojo.Deferred();
 115                 deferred.total = new dojo.Deferred();
 116                 var converter = this._objectConverter(function(object){return object;});
 117                 this.store.fetch(dojo.mixin({
 118                         query: query,
 119                         onBegin: function(count){
 120                                 deferred.total.resolve(count);
 121                         },
 122                         onComplete: function(results){
 123                                 deferred.resolve(dojo.map(results, converter));
 124                         },
 125                         onError: function(error){
 126                                 deferred.reject(error);
 127                         }
 128                 }, options));
 129                 return dojo.store.util.QueryResults(deferred);
 130         },
 131         getIdentity: function(object){
 132                 // summary:
 133                 //              Fetch the identity for the given object.
 134                 // object: Object
 135                 //              The data object to get the identity from.
 136                 // returns: Number
 137                 //              The id of the given object.
 138                 return object[this.idProperty || this.store.getIdentityAttributes()[0]];
 139         }
 140 });
 141
 142 }