Struct tantivy::collector::FilterCollector

pub struct FilterCollector<TCollector, TPredicate, TPredicateValue>
where
    TPredicate: 'static + Clone,
{ /* private fields */ }

The FilterCollector filters docs using a fast field value and a predicate.

Only the documents containing at least one value for which the predicate returns true will be passed on to the next collector.

In other words,

• documents with no values are filtered out.
• documents with several values are accepted if at least one value matches the predicate.

use tantivy::collector::{TopDocs, FilterCollector};
use tantivy::query::QueryParser;
use tantivy::schema::{Schema, TEXT, FAST};
use tantivy::{doc, DocAddress, Index};

let mut schema_builder = Schema::builder();
let title = schema_builder.add_text_field("title", TEXT);
let price = schema_builder.add_u64_field("price", FAST);
let schema = schema_builder.build();
let index = Index::create_in_ram(schema);

let mut index_writer = index.writer_with_num_threads(1, 20_000_000)?;
index_writer.add_document(doc!(title => "The Name of the Wind", price => 30_200u64))?;
index_writer.add_document(doc!(title => "The Diary of Muadib", price => 29_240u64))?;
index_writer.add_document(doc!(title => "A Dairy Cow", price => 21_240u64))?;
index_writer.add_document(doc!(title => "The Diary of a Young Girl", price => 20_120u64))?;
index_writer.commit()?;

let reader = index.reader()?;
let searcher = reader.searcher();

let query_parser = QueryParser::for_index(&index, vec![title]);
let query = query_parser.parse_query("diary")?;
let no_filter_collector = FilterCollector::new("price".to_string(), |value: u64| value > 20_120u64, TopDocs::with_limit(2));
let top_docs = searcher.search(&query, &no_filter_collector)?;

assert_eq!(top_docs.len(), 1);
assert_eq!(top_docs[0].1, DocAddress::new(0, 1));

let filter_all_collector: FilterCollector<_, _, u64> = FilterCollector::new("price".to_string(), |value| value < 5u64, TopDocs::with_limit(2));
let filtered_top_docs = searcher.search(&query, &filter_all_collector)?;

assert_eq!(filtered_top_docs.len(), 0);

Note that this is limited to fast fields which implement the FastValue trait, e.g. u64 but not &[u8]. To filter based on a bytes fast field, use a BytesFilterCollector instead.

Implementations

impl<TCollector, TPredicate, TPredicateValue> FilterCollector<TCollector, TPredicate, TPredicateValue>

where TCollector: Collector + Send + Sync, TPredicate: Fn(TPredicateValue) -> bool + Send + Sync + Clone,

pub fn new(field: String, predicate: TPredicate, collector: TCollector) -> Self

Create a new FilterCollector.

Trait Implementations

impl<TCollector, TPredicate, TPredicateValue> Collector for FilterCollector<TCollector, TPredicate, TPredicateValue>

where TCollector: Collector + Send + Sync, TPredicate: 'static + Fn(TPredicateValue) -> bool + Send + Sync + Clone, TPredicateValue: HasAssociatedColumnType, DynamicColumn: Into<Option<Column<TPredicateValue>>>,

type Fruit = <TCollector as Collector>::Fruit

Fruit is the type for the result of our collection. e.g. usize for the Count collector.

type Child = FilterSegmentCollector<<TCollector as Collector>::Child, TPredicate, TPredicateValue>

Type of the SegmentCollector associated with this collector.

fn for_segment( &self, segment_local_id: u32, segment_reader: &SegmentReader ) -> Result<Self::Child>

set_segment is called before beginning to enumerate on this segment.

fn requires_scoring(&self) -> bool

Returns true iff the collector requires to compute scores for documents.

fn merge_fruits( &self, segment_fruits: Vec<<TCollector::Child as SegmentCollector>::Fruit> ) -> Result<TCollector::Fruit>

Combines the fruit associated with the collection of each segments into one fruit.

fn collect_segment( &self, weight: &dyn Weight, segment_ord: u32, reader: &SegmentReader ) -> Result<<Self::Child as SegmentCollector>::Fruit>

Created a segment collector and