/// <summary>
/// Find existing instance of ProcessManager
/// FindData() and UpdateData() are part of the same transaction.
/// FindData() opens new connection and transaction.
/// UPDLOCK is placed onf the relevant row to prevent reads until the transaction is commited in UpdateData
/// </summary>
/// <typeparam name="T"></typeparam>
/// <returns></returns>
public IPersistanceData <T> FindData <T>(IProcessManagerPropertyMapper mapper, Message message) where T : class, IProcessManagerData
{
var mapping = mapper.Mappings.FirstOrDefault(m => m.MessageType == message.GetType()) ??
mapper.Mappings.First(m => m.MessageType == typeof(Message));
string tableName = typeof(T).Name;
var sbXPath = new StringBuilder();
sbXPath.Append("(/" + tableName);
foreach (var prop in mapping.PropertiesHierarchy.Reverse())
{
sbXPath.Append("/" + prop.Key);
}
sbXPath.Append(")[1]");
XPathExpression xPathExpression;
try
{
xPathExpression = XPathExpression.Compile(sbXPath.ToString());
}
catch (XPathException ex)
{
Logger.ErrorFormat("Error compiling xpath expression. {0}", ex.Message);
throw;
}
// Message Propery Value
object msgPropValue = mapping.MessageProp.Invoke(message);
SqlServerData <T> result = null;
if (!GetTableNameExists(tableName))
{
return(null);
}
using (var sqlConnection = new SqlConnection(_connectionString))
{
sqlConnection.Open();
using (var command = new SqlCommand())
{
command.Connection = sqlConnection;
command.CommandTimeout = _commandTimeout;
command.CommandText = string.Format(@"SELECT * FROM {0} WHERE DataXml.value('{1}', 'nvarchar(max)') = @val", tableName, xPathExpression.Expression);
command.Parameters.Add(new SqlParameter {
ParameterName = "@val", Value = msgPropValue
});
try
{
var reader = command.ExecuteReader(CommandBehavior.SingleResult);
if (reader.HasRows)
{
reader.Read();
var serializer = new XmlSerializer(typeof(T));
object res;
using (TextReader r = new StringReader(reader["DataXml"].ToString()))
{
res = serializer.Deserialize(r);
}
result = new SqlServerData <T>
{
Id = (Guid)reader["Id"],
Data = (T)res,
Version = (int)reader["Version"]
};
}
reader.Dispose();
}
finally
{
sqlConnection.Close();
}
}
}
return(result);
}
/// <summary>
/// Create new instance of ProcessManager
/// When multiple threads try to create new ProcessManager instance, only the first one is allowed.
/// All subsequent threads will update data instead.
/// </summary>
/// <param name="data"></param>
public void InsertData(IProcessManagerData data)
{
string tableName = GetTableName(data);
var sqlServerData = new SqlServerData <IProcessManagerData>
{
Data = data,
Version = 1,
Id = data.CorrelationId
};
var xmlSerializer = new XmlSerializer(data.GetType());
var sww = new StringWriter();
XmlWriter writer = XmlWriter.Create(sww);
xmlSerializer.Serialize(writer, data);
var dataXml = sww.ToString();
using (var sqlConnection = new SqlConnection(_connectionString))
{
sqlConnection.Open();
using (var dbTransaction = sqlConnection.BeginTransaction(IsolationLevel.ReadCommitted))
{
// Insert if doesn't exist, else update (only the first one is allowed)
string upsertSql = string.Format(@"if exists (select * from {0} with (updlock,serializable) WHERE Id = @Id)
begin
UPDATE {0}
SET DataXml = @DataXml, Version = @Version
WHERE Id = @Id
end
else
begin
INSERT {0} (Id, Version, DataXml)
VALUES (@Id,@Version,@DataXml)
end", tableName);
using (var command = new SqlCommand(upsertSql))
{
command.Connection = sqlConnection;
command.Transaction = dbTransaction;
command.Parameters.Add("@Id", SqlDbType.UniqueIdentifier).Value = data.CorrelationId;
command.Parameters.Add("@Version", SqlDbType.Int).Value = sqlServerData.Version;
command.Parameters.Add("@DataXml", SqlDbType.Xml).Value = dataXml;
try
{
command.ExecuteNonQuery();
dbTransaction.Commit();
}
catch
{
dbTransaction.Rollback();
throw;
}
finally
{
sqlConnection.Close();
}
}
}
}
}
