/// <summary>
/// Commit the transaction. Returns an integer representing the number of rows affected by the commit.
/// </summary>
public int Commit()
{
int result = 0;
//Based on the transaction action
switch (Request)
{
case Action.Read:
{
//Release the write access for all rows if the transaction is repeatable read or serialised read
if (Type == TransactionType.RepeatableRead || Type == TransactionType.SerialisedRead)
{
ReleaseRowsWriteAccess(WorkingRows);
}
break;
}
case Action.Update:
{
//Pass the transaction rows to the TableManager for update and release the write access for all rows
result += Manager.UpdateRows(WorkingRows);
ReleaseRowsWriteAccess(WorkingRows);
break;
}
case Action.Delete:
{
//Pass the transaction rows to the TableManager for delete and release the write access for all rows
result += Manager.DeleteRows(WorkingRows);
ReleaseRowsWriteAccess(WorkingRows);
break;
}
case Action.Create:
{
result += WorkingRows.Count;
//Pass the transaction rows to the TableManager for create and release the write access for all rows
Manager.WriteRows(WorkingRows);
ReleaseRowsWriteAccess(WorkingRows);
break;
}
}
//If the transaction is a serialised read, release the table's create access
if (Type == TransactionType.SerialisedRead)
{
Manager.Table.ReleasedSerialisedAccess();
}
//Clear the working rows and return the number affected
WorkingRows.Clear();
return(result);
}
/// <summary>
/// Rollback the transaction. Returns an integer representing the number of rows affected by the rollback.
/// </summary>
public int RollBack()
{
int result = 0;
foreach (Row row in WorkingRows)
{
//If the row is marked as deleted, return it to stable and release it's writer
if (row.Action == Row.RowAction.Delete)
{
row.Action = Row.RowAction.Stable;
result++;
row.Lock.ReleaseWriter();
}
//If the row is marked as update
if (row.Action == Row.RowAction.Update)
{
//Revert it to stable
row.Action = Row.RowAction.Stable;
//Revert the data that reflects the update back to the state that it was before being flagged for update
row.NewTextData = row.TextData;
row.NewNumberData = row.NumberData;
result++;
//Release the writer
row.Lock.ReleaseWriter();
}
if (row.Action == Row.RowAction.Proposed)
{
//If it was proposed then remove the row from the table
Manager.DeleteRowFromTable(row);
result++;
}
}
//If the transaction is a serialised read, release the table's create access
if (Type == TransactionType.SerialisedRead)
{
Manager.Table.ReleasedSerialisedAccess();
}
//Clear the working rows and return the number affected
WorkingRows.Clear();
return(result);
}
