/// <summary>
/// Retrieves the next part of the result.
/// </summary>
/// <returns></returns>
public string Next()
{
if (!hasNextItem)
{
return(null);
}
NetworkOperations.Message msg = new NetworkOperations.Message();
msg.Instruction = InstructionCode.GetNextItem;
NetworkOperations.WriteMessage(msg, outputStream);
NetworkOperations.StringItem item = NetworkOperations.ReadStringItem(inputStream);
if (item.Item == null)
{
hasNextItem = false;
return(null);
}
else
{
text += item.Item;
return(item.Item);
}
}
/// <summary>
/// Executes a query that is read from a stream.
/// </summary>
public QueryResult Execute(TextReader queryReader)
{
try
{
if (!inTransaction)
{
BeginTransaction();
}
string query = queryReader.ReadToEnd();
NetworkOperations.Message msg = new NetworkOperations.Message();
msg.Instruction = InstructionCode.Execute;
MemoryStream stream = new MemoryStream();
BinaryWriter writer = new BinaryWriter(stream);
writer.Write((byte)0); // xml is 0, scheme xml is 1
NetworkOperations.WriteString(writer, query);
writer.Close();
msg.Body = stream.ToArray();
NetworkOperations.WriteMessage(msg, outputStream);
NetworkOperations.ReadMessage(msg, inputStream);
if (msg.Instruction == InstructionCode.QuerySucceeded)
{
return(new QueryResult(NetworkOperations.ReadStringItem(inputStream), inputStream, outputStream));
}
else if (msg.Instruction == InstructionCode.QueryFailed || msg.Instruction == InstructionCode.UpdateFailed || msg.Instruction == InstructionCode.GeneralError)
{
throw NetworkOperations.GetErrorInfo(msg.Instruction, msg.Body);
}
else if (msg.Instruction == InstructionCode.UpdateSucceeded)
{
haveUpdated = true;
return(null);
}
else if (msg.Instruction == InstructionCode.BulkLoadFileRequest)
{
try
{
haveUpdated = true;
string filename = NetworkOperations.ReadString(msg, 0);
Stream fileStream = File.OpenRead(filename);
if (!NetworkOperations.BulkLoad(fileStream, inputStream, outputStream))
{
throw new SednaException(InstructionCode.BulkLoadFailed, "Bulk load failed");
}
return(null);
}
finally
{
stream.Close();
}
}
else if (msg.Instruction == InstructionCode.BulkLoadStreamRequest)
{
if (!NetworkOperations.BulkLoad(Console.OpenStandardInput(), inputStream, outputStream))
{
throw new SednaException("Bulk load failed");
}
return(null);
}
else
{
throw new SednaException("Unexpected error");
}
}
catch (Exception ex)
{
inTransaction = false;
haveUpdated = false;
throw ex;
}
}
