private Filter getFilter() {
        if (filter == null && !filters.isEmpty()) {
            BooleanQuery filterQuery = new BooleanQuery();
            for (Filter filter : filters) {
                filterQuery.add(filter, Occur.SHOULD);
            }
            filter = new QueryWrapperFilter(filterQuery);
        }
        return filter;
    }
Apply the given Lucene filter to the search results

@param filter
           filter
@return the current object
querydsl-lucene5/src/main/java/com/querydsl/lucene5/AbstractLuceneQuery.java