/// <summary>
/// Records that you are now using this IndexSearcher.
/// Always call this when you've obtained a possibly new
/// <seealso cref="IndexSearcher"/>, for example from {@link
/// SearcherManager}. It's fine if you already passed the
/// same searcher to this method before.
///
/// <p>this returns the long token that you can later pass
/// to <seealso cref="#acquire"/> to retrieve the same IndexSearcher.
/// You should record this long token in the search results
/// sent to your user, such that if the user performs a
/// follow-on action (clicks next page, drills down, etc.)
/// the token is returned.
/// </summary>
public virtual long Record(IndexSearcher searcher)
{
EnsureOpen();
// TODO: we don't have to use IR.getVersion to track;
// could be risky (if it's buggy); we could get better
// bug isolation if we assign our own private ID:
long version = ((DirectoryReader)searcher.IndexReader).Version;
SearcherTracker tracker = Searchers[version];
if (tracker == null)
{
//System.out.println("RECORD version=" + version + " ms=" + System.currentTimeMillis());
tracker = new SearcherTracker(searcher);
if (Searchers.AddIfAbsent(version, tracker) != null)
{
// Another thread beat us -- must decRef to undo
// incRef done by SearcherTracker ctor:
tracker.Dispose();
}
}
else if (tracker.Searcher != searcher)
{
throw new System.ArgumentException("the provided searcher has the same underlying reader version yet the searcher instance differs from before (new=" + searcher + " vs old=" + tracker.Searcher);
}
return(version);
}
/// <summary>
/// Retrieve a previously recorded <seealso cref="IndexSearcher"/>, if it
/// has not yet been closed
///
/// <p><b>NOTE</b>: this may return null when the
/// requested searcher has already timed out. When this
/// happens you should notify your user that their session
/// timed out and that they'll have to restart their
/// search.</p>
///
/// <p>If this returns a non-null result, you must match
/// later call <seealso cref="#release"/> on this searcher, best
/// from a finally clause.</p>
/// </summary>
public virtual IndexSearcher Acquire(long version)
{
EnsureOpen();
SearcherTracker tracker = _searchers[version];
if (tracker != null && tracker.Searcher.IndexReader.TryIncRef())
{
return(tracker.Searcher);
}
return(null);
}
