dojo
Version:
Dojo core is a powerful, lightweight library that makes common tasks quicker and easier. Animate elements, manipulate the DOM, and query with easy CSS syntax, all without sacrificing performance.
260 lines (252 loc) • 7.85 kB
JavaScript
define([
"../_base/lang", "../_base/declare", "../Deferred", "../_base/array",
"./util/QueryResults", "./util/SimpleQueryEngine" /*=====, "./api/Store" =====*/
], function(lang, declare, Deferred, array, QueryResults, SimpleQueryEngine /*=====, Store =====*/){
// module:
// dojo/store/DataStore
// No base class, but for purposes of documentation, the base class is dojo/store/api/Store
var base = null;
/*===== base = Store; =====*/
return declare("dojo.store.DataStore", base, {
// summary:
// This is an adapter for using Dojo Data stores with an object store consumer.
// You can provide a Dojo data store and use this adapter to interact with it through
// the Dojo object store API
target: "",
constructor: function(options){
// options: Object?
// This provides any configuration information that will be mixed into the store,
// including a reference to the Dojo data store under the property "store".
lang.mixin(this, options);
if(!("idProperty" in options)){
var idAttribute;
try{
idAttribute = this.store.getIdentityAttributes();
}catch(e){
// some store are not requiring an item instance to give us the ID attributes
// but some other do and throw errors in that case.
}
// if no idAttribute we have implicit id
this.idProperty = (lang.isArray(idAttribute) ? idAttribute[0] : idAttribute) || this.idProperty;
}
var features = this.store.getFeatures();
// check the feature set and null out any methods that shouldn't be available
if(!features["dojo.data.api.Read"]){
this.get = null;
}
if(!features["dojo.data.api.Identity"]){
this.getIdentity = null;
}
if(!features["dojo.data.api.Write"]){
this.put = this.add = null;
}
},
// idProperty: String
// The object property to use to store the identity of the store items.
idProperty: "id",
// store:
// The object store to convert to a data store
store: null,
// queryEngine: Function
// Defines the query engine to use for querying the data store
queryEngine: SimpleQueryEngine,
_objectConverter: function(callback){
var store = this.store;
var idProperty = this.idProperty;
function convert(item){
var object = {};
var attributes = store.getAttributes(item);
for(var i = 0; i < attributes.length; i++){
var attribute = attributes[i];
var values = store.getValues(item, attribute);
if(values.length > 1){
for(var j = 0; j < values.length; j++){
var value = values[j];
if(typeof value == 'object' && store.isItem(value)){
values[j] = convert(value);
}
}
value = values;
}else{
var value = store.getValue(item, attribute);
if(typeof value == 'object' && store.isItem(value)){
value = convert(value);
}
}
object[attributes[i]] = value;
}
if(!(idProperty in object) && store.getIdentity){
object[idProperty] = store.getIdentity(item);
}
return object;
}
return function(item){
return callback(item && convert(item));
};
},
get: function(id, options){
// summary:
// Retrieves an object by it's identity. This will trigger a fetchItemByIdentity
// id: Object?
// The identity to use to lookup the object
var returnedObject, returnedError;
var deferred = new Deferred();
this.store.fetchItemByIdentity({
identity: id,
onItem: this._objectConverter(function(object){
deferred.resolve(returnedObject = object);
}),
onError: function(error){
deferred.reject(returnedError = error);
}
});
if(returnedObject !== undefined){
// if it was returned synchronously
return returnedObject == null ? undefined : returnedObject;
}
if(returnedError){
throw returnedError;
}
return deferred.promise;
},
put: function(object, options){
// summary:
// Stores an object by its identity.
// object: Object
// The object to store.
// options: Object?
// Additional metadata for storing the data. Includes a reference to an id
// that the object may be stored with (i.e. { id: "foo" }).
options = options || {};
var id = typeof options.id != "undefined" ? options.id : this.getIdentity(object);
var store = this.store;
var idProperty = this.idProperty;
var deferred = new Deferred();
if(typeof id == "undefined"){
var item = store.newItem(object);
store.save({
onComplete: function(){
deferred.resolve(item);
},
onError: function(error){
deferred.reject(error);
}
});
}else{
store.fetchItemByIdentity({
identity: id,
onItem: function(item){
if(item){
if(options.overwrite === false){
return deferred.reject(new Error("Overwriting existing object not allowed"));
}
for(var i in object){
if(i != idProperty && // don't copy id properties since they are immutable and should be omitted for implicit ids
object.hasOwnProperty(i) && // don't want to copy methods and inherited properties
store.getValue(item, i) != object[i]){
store.setValue(item, i, object[i]);
}
}
}else{
if(options.overwrite === true){
return deferred.reject(new Error("Creating new object not allowed"));
}
var item = store.newItem(object);
}
store.save({
onComplete: function(){
deferred.resolve(item);
},
onError: function(error){
deferred.reject(error);
}
});
},
onError: function(error){
deferred.reject(error);
}
});
}
return deferred.promise;
},
add: function(object, options){
// summary:
// Creates an object, throws an error if the object already exists
// object: Object
// The object to store.
// options: dojo/store/api/Store.PutDirectives?
// Additional metadata for storing the data. Includes an "id"
// property if a specific id is to be used.
// returns: Number
(options = options || {}).overwrite = false;
// call put with overwrite being false
return this.put(object, options);
},
remove: function(id){
// summary:
// Deletes an object by its identity.
// id: Object
// The identity to use to delete the object
var store = this.store;
var deferred = new Deferred();
this.store.fetchItemByIdentity({
identity: id,
onItem: function(item){
try{
if(item == null){
// no item found, return false
deferred.resolve(false);
}else{
// delete and save the change
store.deleteItem(item);
store.save();
deferred.resolve(true);
}
}catch(error){
deferred.reject(error);
}
},
onError: function(error){
deferred.reject(error);
}
});
return deferred.promise;
},
query: function(query, options){
// summary:
// Queries the store for objects.
// query: Object
// The query to use for retrieving objects from the store
// options: Object?
// Optional options object as used by the underlying dojo.data Store.
// returns: dojo/store/api/Store.QueryResults
// A query results object that can be used to iterate over results.
var fetchHandle;
var deferred = new Deferred(function(){ fetchHandle.abort && fetchHandle.abort(); });
deferred.total = new Deferred();
var converter = this._objectConverter(function(object){return object;});
fetchHandle = this.store.fetch(lang.mixin({
query: query,
onBegin: function(count){
deferred.total.resolve(count);
},
onComplete: function(results){
deferred.resolve(array.map(results, converter));
},
onError: function(error){
deferred.reject(error);
}
}, options));
return QueryResults(deferred);
},
getIdentity: function(object){
// summary:
// Fetch the identity for the given object.
// object: Object
// The data object to get the identity from.
// returns: Number
// The id of the given object.
return object[this.idProperty];
}
});
});