/// <summary>
/// Read next available data item
/// </summary>
/// <returns>
/// <see cref="IDataItemRead"/>
/// <see langword="null"/> if the end is reached (<see cref="HasData"/> will return <see langword="false"/>)
/// </returns>
/// <remarks>
/// The order of data items coming from multiple folders is guaranteed only if item timestamps are different.
/// If more than one folder being read contains data item with a particular timestamp
/// the order in which those data items are read may change next time you read same data from those same folders.
/// Use <see cref="IRepositoryFolder.LastTimestamp"/> to position precisely every single data source.
/// <seealso cref="IRepositoryReader.GetLastItemTimestamp"/>
/// <seealso cref="IDataItemRead.RepositoryFolder"/>
/// </remarks>
/// <exception cref="ObjectDisposedException">
/// The reader has been disposed.
/// </exception>
public IDataItemRead Read()
{
CheckNotDisposed();
IDataItemRead retval = null;
if (this.HasData)
{
retval = new DataItemRead
{
DataItem = TopReader.CurrentItem,
RepositoryFolder = TopReader.TargetFolder
};
TopReader.UpdatePosition();
_position.Update(retval.DataItem);
MoveTopReaderToNextItem();
}
return(retval);
}
public void QuickReaderTest()
{
string targetFolderName = "QuickReaderTest";
IRepositoryFolder targetFolder = FixtureRootRepoFolder.GetSubFolder(targetFolderName);
if (targetFolder != null)
{
targetFolder.Delete(true, true);
}
targetFolder = FixtureRootRepoFolder.CreateSubfolder(targetFolderName);
string targetFolderPath = targetFolder.FullPath;
const int subfolderCount = 3;
const int itemsIntervalHours = 1;
const int desiredFileSize = 2000;
targetFolder.Properties.DesiredItemsPerFile = desiredFileSize;
IRepositoryWriter writer = targetFolder.GetWriter();
IDataRouter dataRouter = new NumberedDataRouter(subfolderCount);
writer.DataRouter = dataRouter;
writer.AllowSubfoldersCreation = true;
DateTime firstTime = DateTime.Now.AddDays(-10);
DateTime lastTime = DateTime.MinValue;
int itemsCount = 100000;
int n;
for (n = 0; n < itemsCount; ++n)
{
Mock.TestDataItem item = Mock.TestDataItem.GetTestItem(n);
lastTime = firstTime.AddHours(n * itemsIntervalHours);
item.DateTime = lastTime;
writer.Write(item);
}
writer.Flush();
writer.Close();
// will test lazy loading
targetFolder.UnloadSubfolders();
Assert.IsTrue(targetFolder.SubFolders.Count == subfolderCount, "Router had to make writer create the configured number of subfolders");
IRepositoryFolder firstItemSubfolder = targetFolder.GetDescendant(
dataRouter.GetRelativePath(Mock.TestDataItem.GetTestItem(0)), false);
Assert.AreEqual(firstTime, firstItemSubfolder.FirstTimestamp
, "Fisrt item timestamp reported incorrectly by Folder.FirstTimestamp");
Assert.AreEqual(firstTime, targetFolder.GetFirstItemTimestamp(true, false)
, "Fisrt item timestamp reported incorrectly by Folder.GetFirstItemTimestamp");
IRepositoryReader reader = targetFolder.GetReader(firstTime, true);
Assert.IsTrue(reader.HasData, "Folder just populated but no data can be read");
IDataItemRead ritem = null;
n = 0;
IRepositoryReader altReader = null;
SeekStatusListener seekStatusListener = new SeekStatusListener();
while (reader.HasData)
{
if (n > 0 && n % 100 == 0)
{
altReader = Repository.ObjectFactory.GetReader(reader.Position, seekStatusListener.HanldeStatus);
}
ritem = reader.Read();
Assert.IsNotNull(ritem, "reader.Read() returned null after returning true from HasData");
Assert.AreNotSame(targetFolder, ritem.RepositoryFolder, "Router failed");
Assert.IsInstanceOf <Mock.TestDataItem>(ritem.DataItem, "Data item read from repository is of different type");
Assert.AreEqual(firstTime.AddHours(n * itemsIntervalHours), ritem.DataItem.DateTime);
((Mock.TestDataItem)ritem.DataItem).Check(n);
if (altReader != null)
{
IDataItemRead altItem = altReader.Read();
Assert.AreEqual(ritem.DataItem.DateTime, altItem.DataItem.DateTime);
Assert.AreEqual(0, seekStatusListener.Statuses.Count);
}
++n;
}
Assert.AreEqual(lastTime, ritem.DataItem.DateTime, "Last item has unexpected timestamp");
Assert.AreEqual(itemsCount, n, "Unexpected number of data items read");
DateTime timestampToSeek = firstTime.AddHours(desiredFileSize / 3 * itemsIntervalHours);
reader.Seek(timestampToSeek);
Assert.IsTrue(reader.HasData, "Repeated Seek after reading all failed");
ritem = reader.Read();
Assert.IsNotNull(ritem);
Assert.AreEqual(timestampToSeek, ritem.DataItem.DateTime, "First read item timestamp unexpected");
reader.Direction = bfs.Repository.Util.EnumerationDirection.Backwards;
Assert.IsTrue(reader.HasData, "No data after reversing in the middle of data");
//ritem = reader.Read();
//Assert.AreEqual<DateTime>(timestampToSeek, ritem.DataItem.DateTime
// , "First read item timestamp unexpected after changing direction");
n = 0;
altReader = null;
while (reader.HasData)
{
if (n > 0 && n % 100 == 0)
{
if (altReader != null)
{
altReader.Dispose();
}
altReader = Repository.ObjectFactory.GetReader(reader.Position, seekStatusListener.HanldeStatus);
}
ritem = reader.Read();
Assert.IsNotNull(ritem, "reader.Read() returned null after returning true from HasData");
Assert.AreEqual(timestampToSeek.AddHours(-n * itemsIntervalHours), ritem.DataItem.DateTime);
if (altReader != null)
{
IDataItemRead altItem = altReader.Read();
Assert.AreEqual(ritem.DataItem.DateTime, altItem.DataItem.DateTime);
}
++n;
}
Assert.AreEqual(firstTime, ritem.DataItem.DateTime, "Did not pick up first item after reversing");
// reversing after reaching end
reader.Direction = bfs.Repository.Util.EnumerationDirection.Forwards;
ritem = reader.Read();
Assert.IsNotNull(ritem, "Did not read firts item reversing after reaching end");
Assert.AreEqual(firstTime, ritem.DataItem.DateTime, "Did not pick up first item after reversing after reaching end");
// cleanup
//targetFolder.Delete(true, false);
//Assert.IsFalse(Directory.Exists(targetFolderPath), "Test repo directory not removed from disk by Delete()");
}
