|Known Indirect Subclasses|
@PublicSpi can expect
that programs compiled against a given version will remain binary compatible with later versions of the
@PublicSpi as per each product's API policy (clients should refer to each product's API policy for
the exact guarantee -- usually binary compatibility is guaranteed at least across minor versions).
@PublicSpiinterfaces and classes are specifically designed to be implemented/extended by clients. Hence, the guarantee of binary compatibility is different to that of
@PublicApielements (if an element is both
@PublicSpi, both guarantees apply).
A custom field searcher will implement this interface if the custom field can be sorted but sorting requires multiple Lucene org.apache.lucene.search.SortField.
It is useful for hierarchical custom fields like CascadingSelectCFType that store parent-child relationship and wish to be sorted by both fields.
If a custom field wishes to sort itself, it can use the much slower method