/// <summary>
/// Performs the data indexing.
/// </summary>
protected override void PerformIndexing()
{
Display("Indexing events using cutoff of " + Cutoff);
Display("\tComputing event counts...");
var fileName = Path.GetTempFileName();
var predicateIndex = new Dictionary <string, int>();
using (var file = new FileStream(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.Read, 4096, FileOptions.DeleteOnClose)) {
var writer = new StreamWriter(new UnclosableStream(file), Encoding.UTF8);
int numEvents = ComputeEventCounts(writer, predicateIndex);
Display("done. " + numEvents + " events");
file.Seek(0, SeekOrigin.Begin);
Display("\tIndexing...");
var fes = new FileEventStream(file);
var eventsToCompare = Index(fes, predicateIndex);
file.Close();
Display("done.");
Display(Sort ? "Sorting and merging events..." : "Collecting events...");
SortAndMerge(eventsToCompare, Sort);
Display("Done indexing.");
}
}
/// <summary>
/// Reads events into a linked list. The predicates associated with each event are
/// counted and any which occur at least N times (cutoff) are added to the
/// <paramref name="predicatesInOut"/> map along with a unique integer index.
/// </summary>
/// <param name="eventStore">A writer to which the events are written to for later processing.</param>
/// <param name="predicatesInOut">The predicates in out.</param>
/// <returns>The number of events readed from the event stream.</returns>
private int ComputeEventCounts(StreamWriter eventStore, Dictionary <string, int> predicatesInOut)
{
int eventCount = 0;
var counter = new Dictionary <string, int>();
//var predicateSet = new Java.HashSet<string>();
var predicateSet = new HashSet <string>();
Event ev;
while ((ev = EventStream.Read()) != null)
{
if (Monitor != null && Monitor.Token.CanBeCanceled)
{
Monitor.Token.ThrowIfCancellationRequested();
}
eventCount++;
eventStore.Write(FileEventStream.ToLine(ev));
Update(ev.Context, predicateSet, counter, Cutoff);
}
predCounts = new int[predicateSet.Count];
int index = 0;
for (var e = predicateSet.GetEnumerator(); e.MoveNext(); index++)
{
if (e.Current != null)
{
predCounts[index] = counter[e.Current];
predicatesInOut.Add(e.Current, index);
}
}
eventStore.Flush();
eventStore.Close();
return(eventCount);
}