NAME

       Lucy::Index::DeletionsWriter - Abstract base class for marking documents as deleted.

SYNOPSIS

           my $polyreader  = $del_writer->get_polyreader;
           my $seg_readers = $polyreader->seg_readers;
           for my $seg_reader (@$seg_readers) {
               my $count = $del_writer->seg_del_count( $seg_reader->get_seg_name );
               ...
           }

DESCRIPTION

       Subclasses of DeletionsWriter provide a low-level mechanism for declaring a document
       deleted from an index.

       Because files in an index are never modified, and because it is not practical to delete
       entire segments, a DeletionsWriter does not actually remove documents from the index.
       Instead, it communicates to a search-time companion DeletionsReader which documents are
       deleted in such a way that it can create a Matcher iterator.

       Documents are truly deleted only when the segments which contain them are merged into new
       ones.

ABSTRACT METHODS

   delete_by_term( [labeled params] )
       Delete all documents in the index that index the supplied term.

       •   field - The name of an indexed field. (If it is not spec'd as "indexed", an error will
           occur.)

       •   term - The term which identifies docs to be marked as deleted.  If "field" is
           associated with an Analyzer, "term" will be processed automatically (so don't pre-
           process it yourself).

   delete_by_query(query)
       Delete all documents in the index that match "query".

       •   query - A Query.

   updated()
       Returns true if there are updates that need to be written.

   seg_del_count(seg_name)
       Return the number of deletions for a given segment.

       •   seg_name - The name of the segment.

INHERITANCE

       Lucy::Index::DeletionsWriter isa Lucy::Index::DataWriter isa Lucy::Object::Obj.