source: Dev/trunk/src/client/dojo/data/ItemFileWriteStore.js @ 485

define(["../_base/lang", "../_base/declare", "../_base/array", "../_base/json", "../_base/kernel",
        "./ItemFileReadStore", "../date/stamp"
], function(lang, declare, arrayUtil, jsonUtil, kernel, ItemFileReadStore, dateStamp){

// module:
//              dojo/data/ItemFileWriteStore

return declare("dojo.data.ItemFileWriteStore", ItemFileReadStore, {
        // summary:
        //              TODOC

        constructor: function(/* object */ keywordParameters){
                // keywordParameters:
                //              The structure of the typeMap object is as follows:
                // |    {
                // |            type0: function || object,
                // |            type1: function || object,
                // |            ...
                // |            typeN: function || object
                // |    }
                //              Where if it is a function, it is assumed to be an object constructor that takes the
                //              value of _value as the initialization parameters.  It is serialized assuming object.toString()
                //              serialization.  If it is an object, then it is assumed
                //              to be an object of general form:
                // |    {
                // |            type: function, //constructor.
                // |            deserialize:    function(value) //The function that parses the value and constructs the object defined by type appropriately.
                // |            serialize:      function(object) //The function that converts the object back into the proper file format form.
                // |    }

                // ItemFileWriteStore extends ItemFileReadStore to implement these additional dojo.data APIs
                this._features['dojo.data.api.Write'] = true;
                this._features['dojo.data.api.Notification'] = true;

                // For keeping track of changes so that we can implement isDirty and revert
                this._pending = {
                        _newItems:{},
                        _modifiedItems:{},
                        _deletedItems:{}
                };

                if(!this._datatypeMap['Date'].serialize){
                        this._datatypeMap['Date'].serialize = function(obj){
                                return dateStamp.toISOString(obj, {zulu:true});
                        };
                }
                //Disable only if explicitly set to false.
                if(keywordParameters && (keywordParameters.referenceIntegrity === false)){
                        this.referenceIntegrity = false;
                }

                // this._saveInProgress is set to true, briefly, from when save() is first called to when it completes
                this._saveInProgress = false;
        },

        referenceIntegrity: true, //Flag that defaultly enabled reference integrity tracking.  This way it can also be disabled pogrammatially or declaratively.

        _assert: function(/* boolean */ condition){
                if(!condition){
                        throw new Error("assertion failed in ItemFileWriteStore");
                }
        },

        _getIdentifierAttribute: function(){
                // this._assert((identifierAttribute === Number) || (dojo.isString(identifierAttribute)));
                return this.getFeatures()['dojo.data.api.Identity'];
        },


/* dojo/data/api/Write */

        newItem: function(/* Object? */ keywordArgs, /* Object? */ parentInfo){
                // summary:
                //              See dojo/data/api/Write.newItem()

                this._assert(!this._saveInProgress);

                if(!this._loadFinished){
                        // We need to do this here so that we'll be able to find out what
                        // identifierAttribute was specified in the data file.
                        this._forceLoad();
                }

                if(typeof keywordArgs != "object" && typeof keywordArgs != "undefined"){
                        throw new Error("newItem() was passed something other than an object");
                }
                var newIdentity = null;
                var identifierAttribute = this._getIdentifierAttribute();
                if(identifierAttribute === Number){
                        newIdentity = this._arrayOfAllItems.length;
                }else{
                        newIdentity = keywordArgs[identifierAttribute];
                        if(typeof newIdentity === "undefined"){
                                throw new Error("newItem() was not passed an identity for the new item");
                        }
                        if(lang.isArray(newIdentity)){
                                throw new Error("newItem() was not passed an single-valued identity");
                        }
                }

                // make sure this identity is not already in use by another item, if identifiers were
                // defined in the file.  Otherwise it would be the item count,
                // which should always be unique in this case.
                if(this._itemsByIdentity){
                        this._assert(typeof this._itemsByIdentity[newIdentity] === "undefined");
                }
                this._assert(typeof this._pending._newItems[newIdentity] === "undefined");
                this._assert(typeof this._pending._deletedItems[newIdentity] === "undefined");

                var newItem = {};
                newItem[this._storeRefPropName] = this;
                newItem[this._itemNumPropName] = this._arrayOfAllItems.length;
                if(this._itemsByIdentity){
                        this._itemsByIdentity[newIdentity] = newItem;
                        //We have to set the identifier now, otherwise we can't look it
                        //up at calls to setValueorValues in parentInfo handling.
                        newItem[identifierAttribute] = [newIdentity];
                }
                this._arrayOfAllItems.push(newItem);

                //We need to construct some data for the onNew call too...
                var pInfo = null;

                // Now we need to check to see where we want to assign this thingm if any.
                if(parentInfo && parentInfo.parent && parentInfo.attribute){
                        pInfo = {
                                item: parentInfo.parent,
                                attribute: parentInfo.attribute,
                                oldValue: undefined
                        };

                        //See if it is multi-valued or not and handle appropriately
                        //Generally, all attributes are multi-valued for this store
                        //So, we only need to append if there are already values present.
                        var values = this.getValues(parentInfo.parent, parentInfo.attribute);
                        if(values && values.length > 0){
                                var tempValues = values.slice(0, values.length);
                                if(values.length === 1){
                                        pInfo.oldValue = values[0];
                                }else{
                                        pInfo.oldValue = values.slice(0, values.length);
                                }
                                tempValues.push(newItem);
                                this._setValueOrValues(parentInfo.parent, parentInfo.attribute, tempValues, false);
                                pInfo.newValue = this.getValues(parentInfo.parent, parentInfo.attribute);
                        }else{
                                this._setValueOrValues(parentInfo.parent, parentInfo.attribute, newItem, false);
                                pInfo.newValue = newItem;
                        }
                }else{
                        //Toplevel item, add to both top list as well as all list.
                        newItem[this._rootItemPropName]=true;
                        this._arrayOfTopLevelItems.push(newItem);
                }

                this._pending._newItems[newIdentity] = newItem;

                //Clone over the properties to the new item
                for(var key in keywordArgs){
                        if(key === this._storeRefPropName || key === this._itemNumPropName){
                                // Bummer, the user is trying to do something like
                                // newItem({_S:"foo"}).  Unfortunately, our superclass,
                                // ItemFileReadStore, is already using _S in each of our items
                                // to hold private info.  To avoid a naming collision, we
                                // need to move all our private info to some other property
                                // of all the items/objects.  So, we need to iterate over all
                                // the items and do something like:
                                //        item.__S = item._S;
                                //        item._S = undefined;
                                // But first we have to make sure the new "__S" variable is
                                // not in use, which means we have to iterate over all the
                                // items checking for that.
                                throw new Error("encountered bug in ItemFileWriteStore.newItem");
                        }
                        var value = keywordArgs[key];
                        if(!lang.isArray(value)){
                                value = [value];
                        }
                        newItem[key] = value;
                        if(this.referenceIntegrity){
                                for(var i = 0; i < value.length; i++){
                                        var val = value[i];
                                        if(this.isItem(val)){
                                                this._addReferenceToMap(val, newItem, key);
                                        }
                                }
                        }
                }
                this.onNew(newItem, pInfo); // dojo/data/api/Notification call
                return newItem; // item
        },

        _removeArrayElement: function(/* Array */ array, /* anything */ element){
                var index = arrayUtil.indexOf(array, element);
                if(index != -1){
                        array.splice(index, 1);
                        return true;
                }
                return false;
        },

        deleteItem: function(/* dojo/data/api/Item */ item){
                // summary:
                //              See dojo/data/api/Write.deleteItem()
                this._assert(!this._saveInProgress);
                this._assertIsItem(item);

                // Remove this item from the _arrayOfAllItems, but leave a null value in place
                // of the item, so as not to change the length of the array, so that in newItem()
                // we can still safely do: newIdentity = this._arrayOfAllItems.length;
                var indexInArrayOfAllItems = item[this._itemNumPropName];
                var identity = this.getIdentity(item);

                //If we have reference integrity on, we need to do reference cleanup for the deleted item
                if(this.referenceIntegrity){
                        //First scan all the attributes of this items for references and clean them up in the map
                        //As this item is going away, no need to track its references anymore.

                        //Get the attributes list before we generate the backup so it
                        //doesn't pollute the attributes list.
                        var attributes = this.getAttributes(item);

                        //Backup the map, we'll have to restore it potentially, in a revert.
                        if(item[this._reverseRefMap]){
                                item["backup_" + this._reverseRefMap] = lang.clone(item[this._reverseRefMap]);
                        }

                        //TODO:  This causes a reversion problem.  This list won't be restored on revert since it is
                        //attached to the 'value'. item, not ours.  Need to back tese up somehow too.
                        //Maybe build a map of the backup of the entries and attach it to the deleted item to be restored
                        //later.  Or just record them and call _addReferenceToMap on them in revert.
                        arrayUtil.forEach(attributes, function(attribute){
                                arrayUtil.forEach(this.getValues(item, attribute), function(value){
                                        if(this.isItem(value)){
                                                //We have to back up all the references we had to others so they can be restored on a revert.
                                                if(!item["backupRefs_" + this._reverseRefMap]){
                                                        item["backupRefs_" + this._reverseRefMap] = [];
                                                }
                                                item["backupRefs_" + this._reverseRefMap].push({id: this.getIdentity(value), attr: attribute});
                                                this._removeReferenceFromMap(value, item, attribute);
                                        }
                                }, this);
                        }, this);

                        //Next, see if we have references to this item, if we do, we have to clean them up too.
                        var references = item[this._reverseRefMap];
                        if(references){
                                //Look through all the items noted as references to clean them up.
                                for(var itemId in references){
                                        var containingItem = null;
                                        if(this._itemsByIdentity){
                                                containingItem = this._itemsByIdentity[itemId];
                                        }else{
                                                containingItem = this._arrayOfAllItems[itemId];
                                        }
                                        //We have a reference to a containing item, now we have to process the
                                        //attributes and clear all references to the item being deleted.
                                        if(containingItem){
                                                for(var attribute in references[itemId]){
                                                        var oldValues = this.getValues(containingItem, attribute) || [];
                                                        var newValues = arrayUtil.filter(oldValues, function(possibleItem){
                                                                return !(this.isItem(possibleItem) && this.getIdentity(possibleItem) == identity);
                                                        }, this);
                                                        //Remove the note of the reference to the item and set the values on the modified attribute.
                                                        this._removeReferenceFromMap(item, containingItem, attribute);
                                                        if(newValues.length < oldValues.length){
                                                                this._setValueOrValues(containingItem, attribute, newValues, true);
                                                        }
                                                }
                                        }
                                }
                        }
                }

                this._arrayOfAllItems[indexInArrayOfAllItems] = null;

                item[this._storeRefPropName] = null;
                if(this._itemsByIdentity){
                        delete this._itemsByIdentity[identity];
                }
                this._pending._deletedItems[identity] = item;

                //Remove from the toplevel items, if necessary...
                if(item[this._rootItemPropName]){
                        this._removeArrayElement(this._arrayOfTopLevelItems, item);
                }
                this.onDelete(item); // dojo/data/api/Notification call
                return true;
        },

        setValue: function(/* dojo/data/api/Item */ item, /* attribute-name-string */ attribute, /* almost anything */ value){
                // summary:
                //              See dojo/data/api/Write.set()
                return this._setValueOrValues(item, attribute, value, true); // boolean
        },

        setValues: function(/* dojo/data/api/Item */ item, /* attribute-name-string */ attribute, /* array */ values){
                // summary:
                //              See dojo/data/api/Write.setValues()
                return this._setValueOrValues(item, attribute, values, true); // boolean
        },

        unsetAttribute: function(/* dojo/data/api/Item */ item, /* attribute-name-string */ attribute){
                // summary:
                //              See dojo/data/api/Write.unsetAttribute()
                return this._setValueOrValues(item, attribute, [], true);
        },

        _setValueOrValues: function(/* dojo/data/api/Item */ item, /* attribute-name-string */ attribute, /* anything */ newValueOrValues, /*boolean?*/ callOnSet){
                this._assert(!this._saveInProgress);

                // Check for valid arguments
                this._assertIsItem(item);
                this._assert(lang.isString(attribute));
                this._assert(typeof newValueOrValues !== "undefined");

                // Make sure the user isn't trying to change the item's identity
                var identifierAttribute = this._getIdentifierAttribute();
                if(attribute == identifierAttribute){
                        throw new Error("ItemFileWriteStore does not have support for changing the value of an item's identifier.");
                }

                // To implement the Notification API, we need to make a note of what
                // the old attribute value was, so that we can pass that info when
                // we call the onSet method.
                var oldValueOrValues = this._getValueOrValues(item, attribute);

                var identity = this.getIdentity(item);
                if(!this._pending._modifiedItems[identity]){
                        // Before we actually change the item, we make a copy of it to
                        // record the original state, so that we'll be able to revert if
                        // the revert method gets called.  If the item has already been
                        // modified then there's no need to do this now, since we already
                        // have a record of the original state.
                        var copyOfItemState = {};
                        for(var key in item){
                                if((key === this._storeRefPropName) || (key === this._itemNumPropName) || (key === this._rootItemPropName)){
                                        copyOfItemState[key] = item[key];
                                }else if(key === this._reverseRefMap){
                                        copyOfItemState[key] = lang.clone(item[key]);
                                }else{
                                        copyOfItemState[key] = item[key].slice(0, item[key].length);
                                }
                        }
                        // Now mark the item as dirty, and save the copy of the original state
                        this._pending._modifiedItems[identity] = copyOfItemState;
                }

                // Okay, now we can actually change this attribute on the item
                var success = false;

                if(lang.isArray(newValueOrValues) && newValueOrValues.length === 0){

                        // If we were passed an empty array as the value, that counts
                        // as "unsetting" the attribute, so we need to remove this
                        // attribute from the item.
                        success = delete item[attribute];
                        newValueOrValues = undefined; // used in the onSet Notification call below

                        if(this.referenceIntegrity && oldValueOrValues){
                                var oldValues = oldValueOrValues;
                                if(!lang.isArray(oldValues)){
                                        oldValues = [oldValues];
                                }
                                for(var i = 0; i < oldValues.length; i++){
                                        var value = oldValues[i];
                                        if(this.isItem(value)){
                                                this._removeReferenceFromMap(value, item, attribute);
                                        }
                                }
                        }
                }else{
                        var newValueArray;
                        if(lang.isArray(newValueOrValues)){
                                // Unfortunately, it's not safe to just do this:
                                //        newValueArray = newValueOrValues;
                                // Instead, we need to copy the array, which slice() does very nicely.
                                // This is so that our internal data structure won't
                                // get corrupted if the user mucks with the values array *after*
                                // calling setValues().
                                newValueArray = newValueOrValues.slice(0, newValueOrValues.length);
                        }else{
                                newValueArray = [newValueOrValues];
                        }

                        //We need to handle reference integrity if this is on.
                        //In the case of set, we need to see if references were added or removed
                        //and update the reference tracking map accordingly.
                        if(this.referenceIntegrity){
                                if(oldValueOrValues){
                                        var oldValues = oldValueOrValues;
                                        if(!lang.isArray(oldValues)){
                                                oldValues = [oldValues];
                                        }
                                        //Use an associative map to determine what was added/removed from the list.
                                        //Should be O(n) performant.  First look at all the old values and make a list of them
                                        //Then for any item not in the old list, we add it.  If it was already present, we remove it.
                                        //Then we pass over the map and any references left it it need to be removed (IE, no match in
                                        //the new values list).
                                        var map = {};
                                        arrayUtil.forEach(oldValues, function(possibleItem){
                                                if(this.isItem(possibleItem)){
                                                        var id = this.getIdentity(possibleItem);
                                                        map[id.toString()] = true;
                                                }
                                        }, this);
                                        arrayUtil.forEach(newValueArray, function(possibleItem){
                                                if(this.isItem(possibleItem)){
                                                        var id = this.getIdentity(possibleItem);
                                                        if(map[id.toString()]){
                                                                delete map[id.toString()];
                                                        }else{
                                                                this._addReferenceToMap(possibleItem, item, attribute);
                                                        }
                                                }
                                        }, this);
                                        for(var rId in map){
                                                var removedItem;
                                                if(this._itemsByIdentity){
                                                        removedItem = this._itemsByIdentity[rId];
                                                }else{
                                                        removedItem = this._arrayOfAllItems[rId];
                                                }
                                                this._removeReferenceFromMap(removedItem, item, attribute);
                                        }
                                }else{
                                        //Everything is new (no old values) so we have to just
                                        //insert all the references, if any.
                                        for(var i = 0; i < newValueArray.length; i++){
                                                var value = newValueArray[i];
                                                if(this.isItem(value)){
                                                        this._addReferenceToMap(value, item, attribute);
                                                }
                                        }
                                }
                        }
                        item[attribute] = newValueArray;
                        success = true;
                }

                // Now we make the dojo/data/api/Notification call
                if(callOnSet){
                        this.onSet(item, attribute, oldValueOrValues, newValueOrValues);
                }
                return success; // boolean
        },

        _addReferenceToMap: function(/* dojo/data/api/Item */ refItem, /* dojo/data/api/Item */ parentItem, /* string */ attribute){
                // summary:
                //              Method to add an reference map entry for an item and attribute.
                // description:
                //              Method to add an reference map entry for an item and attribute.
                // refItem:
                //              The item that is referenced.
                // parentItem:
                //              The item that holds the new reference to refItem.
                // attribute:
                //              The attribute on parentItem that contains the new reference.

                var parentId = this.getIdentity(parentItem);
                var references = refItem[this._reverseRefMap];

                if(!references){
                        references = refItem[this._reverseRefMap] = {};
                }
                var itemRef = references[parentId];
                if(!itemRef){
                        itemRef = references[parentId] = {};
                }
                itemRef[attribute] = true;
        },

        _removeReferenceFromMap: function(/* dojo/data/api/Item */ refItem, /* dojo/data/api/Item */ parentItem, /* string */ attribute){
                // summary:
                //              Method to remove an reference map entry for an item and attribute.
                // description:
                //              Method to remove an reference map entry for an item and attribute.  This will
                //              also perform cleanup on the map such that if there are no more references at all to
                //              the item, its reference object and entry are removed.
                // refItem:
                //              The item that is referenced.
                // parentItem:
                //              The item holding a reference to refItem.
                // attribute:
                //              The attribute on parentItem that contains the reference.
                var identity = this.getIdentity(parentItem);
                var references = refItem[this._reverseRefMap];
                var itemId;
                if(references){
                        for(itemId in references){
                                if(itemId == identity){
                                        delete references[itemId][attribute];
                                        if(this._isEmpty(references[itemId])){
                                                delete references[itemId];
                                        }
                                }
                        }
                        if(this._isEmpty(references)){
                                delete refItem[this._reverseRefMap];
                        }
                }
        },

        _dumpReferenceMap: function(){
                // summary:
                //              Function to dump the reverse reference map of all items in the store for debug purposes.
                // description:
                //              Function to dump the reverse reference map of all items in the store for debug purposes.
                var i;
                for(i = 0; i < this._arrayOfAllItems.length; i++){
                        var item = this._arrayOfAllItems[i];
                        if(item && item[this._reverseRefMap]){
                                console.log("Item: [" + this.getIdentity(item) + "] is referenced by: " + jsonUtil.toJson(item[this._reverseRefMap]));
                        }
                }
        },

        _getValueOrValues: function(/* dojo/data/api/Item */ item, /* attribute-name-string */ attribute){
                var valueOrValues = undefined;
                if(this.hasAttribute(item, attribute)){
                        var valueArray = this.getValues(item, attribute);
                        if(valueArray.length == 1){
                                valueOrValues = valueArray[0];
                        }else{
                                valueOrValues = valueArray;
                        }
                }
                return valueOrValues;
        },

        _flatten: function(/* anything */ value){
                if(this.isItem(value)){
                        // Given an item, return an serializable object that provides a
                        // reference to the item.
                        // For example, given kermit:
                        //        var kermit = store.newItem({id:2, name:"Kermit"});
                        // we want to return
                        //        {_reference:2}
                        return {_reference: this.getIdentity(value)};
                }else{
                        if(typeof value === "object"){
                                for(var type in this._datatypeMap){
                                        var typeMap = this._datatypeMap[type];
                                        if(lang.isObject(typeMap) && !lang.isFunction(typeMap)){
                                                if(value instanceof typeMap.type){
                                                        if(!typeMap.serialize){
                                                                throw new Error("ItemFileWriteStore:  No serializer defined for type mapping: [" + type + "]");
                                                        }
                                                        return {_type: type, _value: typeMap.serialize(value)};
                                                }
                                        }else if(value instanceof typeMap){
                                                //SImple mapping, therefore, return as a toString serialization.
                                                return {_type: type, _value: value.toString()};
                                        }
                                }
                        }
                        return value;
                }
        },

        _getNewFileContentString: function(){
                // summary:
                //              Generate a string that can be saved to a file.
                //              The result should look similar to:
                //              http://trac.dojotoolkit.org/browser/dojo/trunk/tests/data/countries.json
                var serializableStructure = {};

                var identifierAttribute = this._getIdentifierAttribute();
                if(identifierAttribute !== Number){
                        serializableStructure.identifier = identifierAttribute;
                }
                if(this._labelAttr){
                        serializableStructure.label = this._labelAttr;
                }
                serializableStructure.items = [];
                for(var i = 0; i < this._arrayOfAllItems.length; ++i){
                        var item = this._arrayOfAllItems[i];
                        if(item !== null){
                                var serializableItem = {};
                                for(var key in item){
                                        if(key !== this._storeRefPropName && key !== this._itemNumPropName && key !== this._reverseRefMap && key !== this._rootItemPropName){
                                                var valueArray = this.getValues(item, key);
                                                if(valueArray.length == 1){
                                                        serializableItem[key] = this._flatten(valueArray[0]);
                                                }else{
                                                        var serializableArray = [];
                                                        for(var j = 0; j < valueArray.length; ++j){
                                                                serializableArray.push(this._flatten(valueArray[j]));
                                                                serializableItem[key] = serializableArray;
                                                        }
                                                }
                                        }
                                }
                                serializableStructure.items.push(serializableItem);
                        }
                }
                var prettyPrint = true;
                return jsonUtil.toJson(serializableStructure, prettyPrint);
        },

        _isEmpty: function(something){
                // summary:
                //              Function to determine if an array or object has no properties or values.
                // something:
                //              The array or object to examine.
                var empty = true;
                if(lang.isObject(something)){
                        var i;
                        for(i in something){
                                empty = false;
                                break;
                        }
                }else if(lang.isArray(something)){
                        if(something.length > 0){
                                empty = false;
                        }
                }
                return empty; //boolean
        },

        save: function(/* object */ keywordArgs){
                // summary:
                //              See dojo/data/api/Write.save()
                this._assert(!this._saveInProgress);

                // this._saveInProgress is set to true, briefly, from when save is first called to when it completes
                this._saveInProgress = true;

                var self = this;
                var saveCompleteCallback = function(){
                        self._pending = {
                                _newItems:{},
                                _modifiedItems:{},
                                _deletedItems:{}
                        };

                        self._saveInProgress = false; // must come after this._pending is cleared, but before any callbacks
                        if(keywordArgs && keywordArgs.onComplete){
                                var scope = keywordArgs.scope || kernel.global;
                                keywordArgs.onComplete.call(scope);
                        }
                };
                var saveFailedCallback = function(err){
                        self._saveInProgress = false;
                        if(keywordArgs && keywordArgs.onError){
                                var scope = keywordArgs.scope || kernel.global;
                                keywordArgs.onError.call(scope, err);
                        }
                };

                if(this._saveEverything){
                        var newFileContentString = this._getNewFileContentString();
                        this._saveEverything(saveCompleteCallback, saveFailedCallback, newFileContentString);
                }
                if(this._saveCustom){
                        this._saveCustom(saveCompleteCallback, saveFailedCallback);
                }
                if(!this._saveEverything && !this._saveCustom){
                        // Looks like there is no user-defined save-handler function.
                        // That's fine, it just means the datastore is acting as a "mock-write"
                        // store -- changes get saved in memory but don't get saved to disk.
                        saveCompleteCallback();
                }
        },

        revert: function(){
                // summary:
                //              See dojo/data/api/Write.revert()
                this._assert(!this._saveInProgress);

                var identity;
                for(identity in this._pending._modifiedItems){
                        // find the original item and the modified item that replaced it
                        var copyOfItemState = this._pending._modifiedItems[identity];
                        var modifiedItem = null;
                        if(this._itemsByIdentity){
                                modifiedItem = this._itemsByIdentity[identity];
                        }else{
                                modifiedItem = this._arrayOfAllItems[identity];
                        }

                        // Restore the original item into a full-fledged item again, we want to try to
                        // keep the same object instance as if we don't it, causes bugs like #9022.
                        copyOfItemState[this._storeRefPropName] = this;
                        for(var key in modifiedItem){
                                delete modifiedItem[key];
                        }
                        lang.mixin(modifiedItem, copyOfItemState);
                }
                var deletedItem;
                for(identity in this._pending._deletedItems){
                        deletedItem = this._pending._deletedItems[identity];
                        deletedItem[this._storeRefPropName] = this;
                        var index = deletedItem[this._itemNumPropName];

                        //Restore the reverse refererence map, if any.
                        if(deletedItem["backup_" + this._reverseRefMap]){
                                deletedItem[this._reverseRefMap] = deletedItem["backup_" + this._reverseRefMap];
                                delete deletedItem["backup_" + this._reverseRefMap];
                        }
                        this._arrayOfAllItems[index] = deletedItem;
                        if(this._itemsByIdentity){
                                this._itemsByIdentity[identity] = deletedItem;
                        }
                        if(deletedItem[this._rootItemPropName]){
                                this._arrayOfTopLevelItems.push(deletedItem);
                        }
                }
                //We have to pass through it again and restore the reference maps after all the
                //undeletes have occurred.
                for(identity in this._pending._deletedItems){
                        deletedItem = this._pending._deletedItems[identity];
                        if(deletedItem["backupRefs_" + this._reverseRefMap]){
                                arrayUtil.forEach(deletedItem["backupRefs_" + this._reverseRefMap], function(reference){
                                        var refItem;
                                        if(this._itemsByIdentity){
                                                refItem = this._itemsByIdentity[reference.id];
                                        }else{
                                                refItem = this._arrayOfAllItems[reference.id];
                                        }
                                        this._addReferenceToMap(refItem, deletedItem, reference.attr);
                                }, this);
                                delete deletedItem["backupRefs_" + this._reverseRefMap];
                        }
                }

                for(identity in this._pending._newItems){
                        var newItem = this._pending._newItems[identity];
                        newItem[this._storeRefPropName] = null;
                        // null out the new item, but don't change the array index so
                        // so we can keep using _arrayOfAllItems.length.
                        this._arrayOfAllItems[newItem[this._itemNumPropName]] = null;
                        if(newItem[this._rootItemPropName]){
                                this._removeArrayElement(this._arrayOfTopLevelItems, newItem);
                        }
                        if(this._itemsByIdentity){
                                delete this._itemsByIdentity[identity];
                        }
                }

                this._pending = {
                        _newItems:{},
                        _modifiedItems:{},
                        _deletedItems:{}
                };
                return true; // boolean
        },

        isDirty: function(/* item? */ item){
                // summary:
                //              See dojo/data/api/Write.isDirty()
                if(item){
                        // return true if the item is dirty
                        var identity = this.getIdentity(item);
                        return new Boolean(this._pending._newItems[identity] ||
                                this._pending._modifiedItems[identity] ||
                                this._pending._deletedItems[identity]).valueOf(); // boolean
                }else{
                        // return true if the store is dirty -- which means return true
                        // if there are any new items, dirty items, or modified items
                        return !this._isEmpty(this._pending._newItems) ||
                                !this._isEmpty(this._pending._modifiedItems) ||
                                !this._isEmpty(this._pending._deletedItems); // boolean
                }
        },

/* dojo/data/api/Notification */

        onSet: function(/* dojo/data/api/Item */ item,
                                        /*attribute-name-string*/ attribute,
                                        /*object|array*/ oldValue,
                                        /*object|array*/ newValue){
                // summary:
                //              See dojo/data/api/Notification.onSet()

                // No need to do anything. This method is here just so that the
                // client code can connect observers to it.
        },

        onNew: function(/* dojo/data/api/Item */ newItem, /*object?*/ parentInfo){
                // summary:
                //              See dojo/data/api/Notification.onNew()

                // No need to do anything. This method is here just so that the
                // client code can connect observers to it.
        },

        onDelete: function(/* dojo/data/api/Item */ deletedItem){
                // summary:
                //              See dojo/data/api/Notification.onDelete()

                // No need to do anything. This method is here just so that the
                // client code can connect observers to it.
        },

        close: function(/* object? */ request){
                 // summary:
                 //             Over-ride of base close function of ItemFileReadStore to add in check for store state.
                 // description:
                 //             Over-ride of base close function of ItemFileReadStore to add in check for store state.
                 //             If the store is still dirty (unsaved changes), then an error will be thrown instead of
                 //             clearing the internal state for reload from the url.

                 //Clear if not dirty ... or throw an error
                 if(this.clearOnClose){
                         if(!this.isDirty()){
                                 this.inherited(arguments);
                         }else{
                                 //Only throw an error if the store was dirty and we were loading from a url (cannot reload from url until state is saved).
                                 throw new Error("dojo.data.ItemFileWriteStore: There are unsaved changes present in the store.  Please save or revert the changes before invoking close.");
                         }
                 }
        }
});

});