//-------------------------------------------------------
// Record traversal methods
//-------------------------------------------------------
/// <summary>
/// Retrieve next record. Returns true if record exists and false if no more
/// records are available.
/// This method will block until a record is retrieved or the query is cancelled.
/// </summary>
public bool Next()
{
if (!valid)
{
executor.CheckForException();
return(false);
}
try
{
record = queue.Take(cancelToken);
}
catch (OperationCanceledException)
{
valid = false;
executor.CheckForException();
return(false);
}
if (record == END)
{
valid = false;
executor.CheckForException();
return(false);
}
return(true);
}
