Expert: represents a single commit into an index as seen by the /// {@link IndexDeletionPolicy}. ///
/// Changes to the content of an index are made visible only
/// after the writer who made that change had written to the
/// directory a new segments file (segments_N
). This point in
/// time, when the action of writing of a new segments file to the
/// directory is completed, is therefore an index commit point.
///
/// Each index commit point has a unique segments file associated /// with it. The segments file associated with a later /// index commit point would have a larger N. ///
segments_N
) associated
/// with this commit point.
/// /// Upon calling this, the writer is notified that this commit /// point should be deleted. ///
/// Decision that a commit-point should be deleted is taken by the {@link IndexDeletionPolicy} in effect /// and therefore this should only be called by its {@link IndexDeletionPolicy#onInit onInit()} or /// {@link IndexDeletionPolicy#onCommit onCommit()} methods. ///