/**
* Reads events from <tt>eventStream</tt> into a linked list. The predicates associated with each
* event are counted and any which occur at least <tt>cutoff</tt> times are added to the
* <tt>predicatesInOut</tt> map along with a unique integer index.
*
* @param eventStream an <code>EventStream</code> value
* @param eventStore a writer to which the events are written to for later processing.
* @param predicatesInOut a <code>TObjectIntHashMap</code> value
* @param cutoff an <code>int</code> value
*/
private int computeEventCounts(
EventStream eventStream, Writer eventStore, TObjectIntHashMap predicatesInOut, int cutoff)
throws IOException {
TObjectIntHashMap counter = new TObjectIntHashMap();
int predicateIndex = 0;
int eventCount = 0;
while (eventStream.hasNext()) {
Event ev = eventStream.nextEvent();
eventCount++;
eventStore.write(FileEventStream.toLine(ev));
String[] ec = ev.getContext();
for (int j = 0; j < ec.length; j++) {
if (!predicatesInOut.containsKey(ec[j])) {
if (counter.increment(ec[j])) {
} else {
counter.put(ec[j], 1);
}
if (counter.get(ec[j]) >= cutoff) {
predicatesInOut.put(ec[j], predicateIndex++);
counter.remove(ec[j]);
}
}
}
}
predicatesInOut.trimToSize();
eventStore.close();
return eventCount;
}
