org.apache.lucene.search

Class IndexSearcher

  • Direct Known Subclasses:
    SolrIndexSearcher, SuggestIndexSearcher, ToParentBlockJoinIndexSearcher


    public class IndexSearcher
    extends Object
    Implements search over a single IndexReader.

    Applications usually need only call the inherited search(Query,int) method. For performance reasons, if your index is unchanging, you should share a single IndexSearcher instance across multiple searches instead of creating a new one per-search. If your index has changed and you wish to see the changes reflected in searching, you should use DirectoryReader.openIfChanged(DirectoryReader) to obtain a new reader and then create a new IndexSearcher from that. Also, for low-latency turnaround it's best to use a near-real-time reader (DirectoryReader.open(IndexWriter)). Once you have a new IndexReader, it's relatively cheap to create a new IndexSearcher from it.

    NOTE: IndexSearcher instances are completely thread safe, meaning multiple threads can call any of its methods, concurrently. If your application requires external synchronization, you should not synchronize on the IndexSearcher instance; use your own (non-Lucene) objects instead.