Method IsCurrent

Check whether any new changes have occurred to the index since this reader was opened.

If this reader was created by calling an overload of Open(Directory), then this method checks if any further commits (see Commit()) have occurred in the directory.

If instead this reader is a near real-time reader (ie, obtained by a call to Open(IndexWriter, Boolean), or by calling an overload of OpenIfChanged(DirectoryReader) on a near real-time reader), then this method checks if either a new commit has occurred, or any new uncommitted changes have taken place via the writer. Note that even if the writer has only performed merging, this method will still return false.

In any event, if this returns false, you should call an overload of OpenIfChanged(DirectoryReader) to get a new reader that sees the changes.