/// <summary>Null value is handled via [BsonIgnoreIfNull] attribute and is not expected here.</summary>
public override TKey Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
{
// Read key as string in semicolon delimited format
// with collection name followed by the equal sign
// as prefix, for example:
//
// CollectionName=KeyElement1;KeyElement2
string str = context.Reader.ReadString();
// Confirm that collection name prefix matches
// the expected collection name for the type
// followed by the equal sign (=).
string[] strTokens = str.Split(new char[] { '=' }, 2);
string collectionName = DataTypeInfo.GetOrCreate(typeof(TKey)).GetCollectionName();
if (strTokens.Length != 2 || strTokens[0] != collectionName)
{
throw new Exception(
$"Key {str} does not start from the expected " +
$"collection name {collectionName} followed by the equal sign (=).");
}
// Deserialize key from the part of the string
// after the equal sign (=).
string keyStr = strTokens[1];
var key = new TKey();
key.PopulateFrom(keyStr);
return(key);
}
/// <summary>
/// Write start document tags. This method
/// should be called only once for the entire document.
/// </summary>
public void WriteStartDocument(string rootElementName)
{
// Check transition matrix
if (currentState_ == TreeWriterState.Empty && elementStack_.Count == 0)
{
currentState_ = TreeWriterState.DocumentStarted;
}
else
{
throw new Exception(
$"A call to WriteStartDocument(...) must be the first call to the tree writer.");
}
// Get root XML element name using mapped final type of the object
string rootName = currentDict_.GetType().Name;
// Check that the name matches
if (rootElementName != rootName)
{
throw new Exception(
$"Attempting to deserialize data for type {rootElementName} into type {rootName}.");
}
rootElementName_ = rootElementName;
currentElementName_ = rootElementName;
var currentDictInfoList = DataTypeInfo.GetOrCreate(currentDict_).DataElements;
currentDictElements_ = new Dictionary <string, PropertyInfo>();
foreach (var elementInfo in currentDictInfoList)
{
currentDictElements_.Add(elementInfo.Name, elementInfo);
}
currentArray_ = null;
currentArrayItemType_ = null;
}
/// <summary>Null value is handled via [BsonIgnoreIfNull] attribute and is not expected here.</summary>
public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, TKey value)
{
// Serialize key in semicolon delimited format,
// with collection name followed by the equal sign
// as prefix, for example:
//
// CollectionName=KeyElement1;KeyElement2
string collectionName = DataTypeInfo.GetOrCreate(typeof(TKey)).GetCollectionName();
string keyStr = value.ToString();
string str = string.Join("=", collectionName, keyStr);
context.Writer.WriteString(str);
}
/// <summary>
/// Populate key elements by taking them from the matching
/// elements of the argument record.
/// </summary>
public void PopulateFrom(TypedRecord <TKey, TRecord> record)
{
// Assign elements of the record to the matching elements
// of the key. This will also make string representation
// of the key return the proper value for the record.
//
// Get PropertyInfo arrays for TKey and TRecord
var dataElementInfoDict = DataTypeInfo.GetOrCreate <TRecord>().DataElementDict;
var keyElementInfoArray = DataTypeInfo.GetOrCreate <TKey>().DataElements;
// Check that TRecord has the same or greater number of elements
// as TKey (all elements of TKey must also be present in TRecord)
if (dataElementInfoDict.Count < keyElementInfoArray.Length)
{
throw new Exception(
$"Record type {typeof(TRecord).Name} has fewer elements than key type {typeof(TKey).Name}.");
}
// Iterate over the key elements
foreach (var keyElementInfo in keyElementInfoArray)
{
if (!dataElementInfoDict.TryGetValue(keyElementInfo.Name, out var dataElementInfo))
{
throw new Exception(
$"Element {keyElementInfo.Name} of key type {typeof(TKey).Name} " +
$"is not found in the record type {typeof(TRecord).Name}.");
}
if (keyElementInfo.PropertyType != dataElementInfo.PropertyType)
{
throw new Exception(
$"Element {typeof(TKey).Name} has type {keyElementInfo.PropertyType.Name} which does not " +
$"match the type {dataElementInfo.PropertyType.Name} of the corresponding element in the " +
$"record type {typeof(TRecord).Name}.");
}
// Read from the record and assign to the key
object elementValue = dataElementInfo.GetValue(record);
keyElementInfo.SetValue(this, elementValue);
}
}
/// <summary>Serialize by writing into ITreeWriter.</summary>
public void SerializeTo(ITreeWriter writer)
{
// Write start tag
writer.WriteStartDict();
// Iterate over the list of elements
var innerElementInfoList = DataTypeInfo.GetOrCreate(this).DataElements;
foreach (var innerElementInfo in innerElementInfoList)
{
// Get element name and value
string innerElementName = innerElementInfo.Name;
object innterElementValue = innerElementInfo.GetValue(this);
// Serialize based on type of element value
switch (innterElementValue)
{
case null:
// Do not serialize null value
break;
case string stringValue:
case double doubleValue:
case bool boolValue:
case int intValue:
case long longValue:
case LocalDate dateValue:
case LocalTime timeValue:
case LocalMinute minuteValue:
case LocalDateTime dateTimeValue:
case Instant instantValue:
case Enum enumValue:
// Embedded as string value
writer.WriteValueElement(innerElementName, innterElementValue);
break;
case IEnumerable enumerableElement:
// Embedded enumerable such as array or list
enumerableElement.SerializeTo(innerElementName, writer);
break;
case Data dataElement:
if (dataElement is Key)
{
// Embedded as string key
writer.WriteValueElement(innerElementName, innterElementValue);
break;
}
else
{
// Embedded as data
writer.WriteStartElement(innerElementName);
dataElement.SerializeTo(writer);
writer.WriteEndElement(innerElementName);
}
break;
case TemporalId idElement:
// Do not serialize
break;
default:
// Argument type is unsupported, error message
throw new Exception($"Element type {innerElementInfo.PropertyType} is not supported for tree serialization.");
}
}
// Write end tag
writer.WriteEndDict();
}
/// <summary>Deserialize from data in ITreeReader.</summary>
public void DeserializeFrom(ITreeReader reader)
{
// Do nothing if the selected XML node is empty
if (reader == null)
{
return;
}
// Iterate over the list of elements
var elementInfoList = DataTypeInfo.GetOrCreate(this).DataElements;
foreach (var elementInfo in elementInfoList)
{
// Get element name and type
string elementName = elementInfo.Name;
Type elementType = elementInfo.PropertyType;
// Get inner XML node, continue with next element if null
ITreeReader innerXmlNode = reader.ReadElement(elementName);
if (innerXmlNode == null)
{
continue;
}
// First check for each of the supported value types
if (elementType == typeof(string))
{
string token = innerXmlNode.ReadValue();
elementInfo.SetValue(this, token);
}
else if (elementType == typeof(double) || elementType == typeof(double?))
{
string token = innerXmlNode.ReadValue();
var value = double.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(bool) || elementType == typeof(bool?))
{
string token = innerXmlNode.ReadValue();
var value = bool.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(int) || elementType == typeof(int?))
{
string token = innerXmlNode.ReadValue();
var value = int.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(long) || elementType == typeof(long?))
{
string token = innerXmlNode.ReadValue();
var value = long.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(LocalDate) || elementType == typeof(LocalDate?))
{
string token = innerXmlNode.ReadValue();
var value = LocalDateUtil.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(LocalTime) || elementType == typeof(LocalTime?))
{
string token = innerXmlNode.ReadValue();
var value = LocalTimeUtil.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(LocalMinute) || elementType == typeof(LocalMinute?))
{
string token = innerXmlNode.ReadValue();
var value = LocalMinuteUtil.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(LocalDateTime) || elementType == typeof(LocalDateTime?))
{
string token = innerXmlNode.ReadValue();
var value = LocalDateTimeUtil.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType == typeof(Instant) || elementType == typeof(Instant?))
{
string token = innerXmlNode.ReadValue();
var value = InstantUtil.Parse(token);
elementInfo.SetValue(this, value);
}
else if (elementType.IsSubclassOf(typeof(Enum)))
{
string token = innerXmlNode.ReadValue();
var value = Enum.Parse(elementType, token);
elementInfo.SetValue(this, value);
}
else
{
// If none of the supported atomic types match, use the activator
// to create and empty instance of a complex type and populate it
var element = Activator.CreateInstance(elementType);
switch (element)
{
case IList listElement:
listElement.DeserializeFrom(elementName, reader);
break;
case Data dataElement:
var keyElement = dataElement as Key;
if (keyElement != null)
{
// Deserialize key from value node containing semicolon delimited string
string token = innerXmlNode.ReadValue();
// Parse semicolon delimited string to populate key elements
keyElement.PopulateFrom(token);
}
else
{
// Deserialize embedded data object from the contents of inner XML node
dataElement.DeserializeFrom(innerXmlNode);
}
break;
case TemporalId idElement:
// Do not serialize
break;
default:
// Error message if the type does not match any of the value or reference types
throw new Exception($"Serialization is not supported for type {elementType}.");
}
// Assign the populated key to the property
elementInfo.SetValue(this, element);
}
}
}
//--- PRIVATE
/// <summary>
/// Populate key elements from an array of tokens starting
/// at the specified token index. Elements that are themselves
/// keys may use more than one token.
///
/// This method returns the index of the first unused token.
/// The returned value is the same as the length of the tokens
/// array if all tokens are used.
///
/// If key AKey has two elements, B and C, where
///
/// * B has type BKey which has two string elements, and
/// * C has type string,
///
/// the semicolon delimited key has the following format:
///
/// BToken1;BToken2;CToken
///
/// To avoid serialization format uncertainty, key elements
/// can have any atomic type except Double.
/// </summary>
private int PopulateFrom(string[] tokens, int tokenIndex)
{
// Get key elements using reflection
var elementInfoArray = DataTypeInfo.GetOrCreate(this).DataElements;
// If singleton is detected process it separately, then exit
if (elementInfoArray.Length == 0)
{
// Check that string key is empty
if (tokens.Length != 1 || tokens[0] != String.Empty)
{
throw new Exception($"Type {GetType()} has key {string.Join(";", tokens)} while " +
$"for a singleton the key must be an empty string (String.Empty). " +
$"Singleton key is a key that has no key elements.");
}
// Return the length of empty key which consists of one (empty) token
return(1);
}
// Check that there are enough remaining tokens in the key for each key element
if (tokens.Length - tokenIndex < elementInfoArray.Length)
{
throw new Exception(
$"Key of type {GetType().Name} requires at least {elementInfoArray.Length} elements " +
$"{String.Join(";", elementInfoArray.Select(p => p.Name).ToArray())} while there are " +
$"only {tokens.Length - tokenIndex} remaining key tokens: {string.Join(";", tokens)}.");
}
// Iterate over element info elements, advancing tokenIndex by the required
// number of tokens for each element. In case of embedded keys, the value of
// tokenIndex is advanced by the recursive call to InitFromTokens method
// of the embedded key.
foreach (var elementInfo in elementInfoArray)
{
// Get element type
Type elementType = elementInfo.PropertyType;
// Convert string token to value depending on elementType
if (elementType == typeof(string))
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
elementInfo.SetValue(this, token);
}
else if (elementType == typeof(double) || elementType == typeof(double?))
{
throw new Exception(
$"Key element {elementInfo.Name} has type Double. Elements of this type " +
$"cannot be part of key due to serialization format uncertainty.");
}
else if (elementType == typeof(bool) || elementType == typeof(bool?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
bool tokenValue = bool.Parse(token);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(int) || elementType == typeof(int?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
int tokenValue = int.Parse(token);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(long) || elementType == typeof(long?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
long tokenValue = long.Parse(token);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(LocalDate) || elementType == typeof(LocalDate?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
// Inside the key, LocalDate is represented as readable int in
// non-delimited yyyymmdd format, not as delimited ISO string.
//
// First parse the string to int, then convert int to LocalDate.
string token = tokens[tokenIndex++];
if (!Int32.TryParse(token, out int isoInt))
{
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type LocalDate and value {token} " +
$"that cannot be converted to readable int in non-delimited yyyymmdd format.");
}
LocalDate tokenValue = LocalDateUtil.FromIsoInt(isoInt);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(LocalTime) || elementType == typeof(LocalTime?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
// Inside the key, LocalTime is represented as readable int in
// non-delimited hhmmssfff format, not as delimited ISO string.
//
// First parse the string to int, then convert int to LocalTime.
string token = tokens[tokenIndex++];
if (!Int32.TryParse(token, out int isoInt))
{
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type LocalTime and value {token} " +
$"that cannot be converted to readable int in non-delimited hhmmssfff format.");
}
LocalTime tokenValue = LocalTimeUtil.FromIsoInt(isoInt);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(LocalMinute) || elementType == typeof(LocalMinute?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
// Inside the key, LocalMinute is represented as readable int in
// non-delimited hhmm format, not as delimited ISO string.
//
// First parse the string to int, then convert int to LocalTime.
string token = tokens[tokenIndex++];
if (!Int32.TryParse(token, out int isoInt))
{
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type LocalMinute and value {token} " +
$"that cannot be converted to readable int in non-delimited hhmm format.");
}
LocalMinute tokenValue = LocalMinuteUtil.FromIsoInt(isoInt);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(LocalDateTime) || elementType == typeof(LocalDateTime?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
// Inside the key, LocalDateTime is represented as readable long in
// non-delimited yyyymmddhhmmssfff format, not as delimited ISO string.
//
// First parse the string to long, then convert int to LocalDateTime.
string token = tokens[tokenIndex++];
if (!Int64.TryParse(token, out long isoLong))
{
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type LocalDateTime and value {token} " +
$"that cannot be converted to readable long in non-delimited yyyymmddhhmmssfff format.");
}
LocalDateTime tokenValue = LocalDateTimeUtil.FromIsoLong(isoLong);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(Instant) || elementType == typeof(Instant?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
// Inside the key, Instant is represented as readable long in
// non-delimited yyyymmddhhmmssfff format, not as delimited ISO string.
//
// First parse the string to long, then convert int to Instant.
string token = tokens[tokenIndex++];
if (!Int64.TryParse(token, out long isoLong))
{
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type Instant and value {token} " +
$"that cannot be converted to readable long in non-delimited yyyymmddhhmmssfff format.");
}
Instant tokenValue = InstantUtil.FromIsoLong(isoLong);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType == typeof(TemporalId) || elementType == typeof(TemporalId?))
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
TemporalId tokenValue = TemporalId.Parse(token);
elementInfo.SetValue(this, tokenValue);
}
else if (elementType.BaseType == typeof(Enum)) // TODO Support nullable Enum in key
{
CheckTokenNotEmpty(tokens, tokenIndex);
string token = tokens[tokenIndex++];
object tokenValue = Enum.Parse(elementType, token);
elementInfo.SetValue(this, tokenValue);
}
else if (typeof(Key).IsAssignableFrom(elementType))
{
Key keyElement = (Key)Activator.CreateInstance(elementType);
tokenIndex = keyElement.PopulateFrom(tokens, tokenIndex);
elementInfo.SetValue(this, keyElement);
}
else
{
// Field type is unsupported for a key, error message
throw new Exception(
$"Element {elementInfo.Name} of key type {GetType().Name} has type {elementType} that " +
$"is not one of the supported key element types. Available key element types are " +
$"string, bool, int, long, LocalDate, LocalTime, LocalMinute, LocalDateTime, Instant, Enum, or Key.");
}
}
return(tokenIndex);
}
/// <summary>
/// Write dictionary start tag. A call to this method
/// must follow WriteStartElement(...) or WriteStartArrayItem().
/// </summary>
public void WriteStartDict()
{
// Push state before defining dictionary state
PushState();
// Check state transition matrix
if (currentState_ == TreeWriterState.DocumentStarted)
{
currentState_ = TreeWriterState.DictStarted;
// Return if this call follows StartDocument, all setup is done in StartDocument
return;
}
else if (currentState_ == TreeWriterState.ElementStarted)
{
currentState_ = TreeWriterState.DictStarted;
}
else if (currentState_ == TreeWriterState.ArrayItemStarted)
{
currentState_ = TreeWriterState.DictArrayItemStarted;
}
else
{
throw new Exception(
$"A call to WriteStartDict() must follow WriteStartElement(...) or WriteStartArrayItem().");
}
// Set dictionary info
Type createdDictType = null;
if (currentArray_ != null)
{
createdDictType = currentArrayItemType_;
}
else if (currentDict_ != null)
{
createdDictType = currentElementInfo_.PropertyType;
}
else
{
throw new Exception($"Value can only be added to a dictionary or array.");
}
object createdDictObj = Activator.CreateInstance(createdDictType);
if (!(createdDictObj is Data)) // TODO Also support native dictionaries
{
string className = currentElementInfo_.PropertyType.Name;
throw new Exception(
$"Element {currentElementInfo_.Name} of type {className} does not implement Data.");
}
var createdDict = (Data)createdDictObj;
// Add to array or dictionary, depending on what we are inside of
if (currentArray_ != null)
{
currentArray_[currentArray_.Count - 1] = createdDict;
}
else if (currentDict_ != null)
{
currentElementInfo_.SetValue(currentDict_, createdDict);
}
else
{
throw new Exception($"Value can only be added to a dictionary or array.");
}
currentDict_ = (Data)createdDict;
var currentDictInfoList = DataTypeInfo.GetOrCreate(createdDictType).DataElements;
currentDictElements_ = new Dictionary <string, PropertyInfo>();
foreach (var elementInfo in currentDictInfoList)
{
currentDictElements_.Add(elementInfo.Name, elementInfo);
}
currentArray_ = null;
currentArrayItemType_ = null;
}
//--- PRIVATE
/// <summary>
/// Returned object holds two collection references - one for the base
/// type of all records and the other for the record type specified
/// as generic parameter.
///
/// The need to hold two collection arises from the requirement
/// that query for a derived type takes into account that another
/// record with the same key and later dataset or object timestamp
/// may exist. For this reason, the typed collection is used for
/// LINQ constraints and base collection is used to iterate over
/// objects.
///
/// This method also creates indices if they do not exist. The
/// two default indices are always created: one for optimizing
/// loading by key and the other by query.
///
/// Additional indices may be created using class attribute
/// [IndexElements] for further performance optimization.
/// </summary>
private TemporalMongoCollection <TRecord> GetOrCreateCollection <TRecord>()
where TRecord : Record
{
// Check if collection object has already been cached
// for this type and return cached result if found
if (collectionDict_.TryGetValue(typeof(TRecord), out object collectionObj))
{
var cachedResult = collectionObj.CastTo <TemporalMongoCollection <TRecord> >();
return(cachedResult);
}
// Check that hierarchical discriminator convention is set for TRecord
var discriminatorConvention = BsonSerializer.LookupDiscriminatorConvention(typeof(TRecord));
if (!discriminatorConvention.Is <HierarchicalDiscriminatorConvention>())
{
throw new Exception(
$"Hierarchical discriminator convention is not set for type {typeof(TRecord).Name}. " +
$"The convention should have been set set in the static constructor of " +
$"MongoDataSource");
}
// Collection name is root class name of the record without prefix
string collectionName = DataTypeInfo.GetOrCreate <TRecord>().GetCollectionName();
// Get interfaces to base and typed collections for the same name
var baseCollection = Db.GetCollection <Record>(collectionName);
var typedCollection = Db.GetCollection <TRecord>(collectionName);
//--- Load standard index types
// Each data type has an index for optimized loading by key.
// This index consists of Key in ascending order, followed by
// DataSet and ID in descending order.
var loadIndexKeys = Builders <TRecord> .IndexKeys
.Ascending(new StringFieldDefinition <TRecord>("_key")) // .Key
.Descending(new StringFieldDefinition <TRecord>("_dataset")) // .DataSet
.Descending(new StringFieldDefinition <TRecord>("_id")); // .Id
// Use index definition convention to specify the index name
var loadIndexName = "Key-DataSet-Id";
var loadIndexModel = new CreateIndexModel <TRecord>(loadIndexKeys, new CreateIndexOptions {
Name = loadIndexName
});
typedCollection.Indexes.CreateOne(loadIndexModel);
//--- Load custom index types
// Additional indices are provided using IndexAttribute for the class.
// Get a sorted dictionary of (definition, name) pairs
// for the inheritance chain of the specified type.
var indexDict = IndexElementsAttribute.GetAttributesDict <TRecord>();
// Iterate over the dictionary to define the index
foreach (var indexInfo in indexDict)
{
string indexDefinition = indexInfo.Key;
string indexName = indexInfo.Value;
// Parse index definition to get a list of (ElementName,SortOrder) tuples
List <(string, int)> indexTokens = IndexElementsAttribute.ParseDefinition <TRecord>(indexDefinition);
var indexKeysBuilder = Builders <TRecord> .IndexKeys;
IndexKeysDefinition <TRecord> indexKeys = null;
// Iterate over (ElementName,SortOrder) tuples
foreach (var indexToken in indexTokens)
{
(string elementName, int sortOrder) = indexToken;
if (indexKeys == null)
{
// Create from builder for the first element
if (sortOrder == 1)
{
indexKeys = indexKeysBuilder.Ascending(new StringFieldDefinition <TRecord>(elementName));
}
else if (sortOrder == -1)
{
indexKeys = indexKeysBuilder.Descending(new StringFieldDefinition <TRecord>(elementName));
}
else
{
throw new Exception("Sort order must be 1 or -1.");
}
}
else
{
// Chain to the previous list of index keys for the remaining elements
if (sortOrder == 1)
{
indexKeys = indexKeys.Ascending(new StringFieldDefinition <TRecord>(elementName));
}
else if (sortOrder == -1)
{
indexKeys = indexKeys.Descending(new StringFieldDefinition <TRecord>(elementName));
}
else
{
throw new Exception("Sort order must be 1 or -1.");
}
}
}
if (indexName == null)
{
throw new Exception("Index name cannot be null.");
}
var indexModel = new CreateIndexModel <TRecord>(indexKeys, new CreateIndexOptions {
Name = indexName
});
// Add to indexes for the collection
typedCollection.Indexes.CreateOne(indexModel);
}
// Create result that holds both base and typed collections
TemporalMongoCollection <TRecord> result = new TemporalMongoCollection <TRecord>(this, baseCollection, typedCollection);
// Add the result to the collection dictionary and return
collectionDict_.TryAdd(typeof(TRecord), result);
return(result);
}