TotalHitCountCollectorManager (Lucene 10.5.1 core API)
Description: declaration: package: org.apache.lucene.search, class: TotalHitCountCollectorManager

Package org.apache.lucene.search

# Class TotalHitCountCollectorManager

java.lang.Object
org.apache.lucene.search.TotalHitCountCollectorManager

All Implemented Interfaces:
  `CollectorManager<TotalHitCountCollector,Integer>`

public class TotalHitCountCollectorManager extends Object implements CollectorManager<TotalHitCountCollector,Integer>
Collector manager based on `TotalHitCountCollector` that allows users to parallelize counting the number of hits, expected to be used mostly wrapped in `MultiCollectorManager`. For cases when this is the only collector manager used, `IndexSearcher.count(Query)` should be called instead of `IndexSearcher.search(Query, CollectorManager)` as the former is faster whenever the count can be returned directly from the index statistics.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `TotalHitCountCollectorManager(IndexSearcher.LeafSlice[] leafSlices)`
  Creates a new total hit count collector manager, providing the array of leaf slices that search targets, which can be retrieved via `IndexSearcher.getSlices()` for the searcher.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `TotalHitCountCollector`
  `newCollector()`
  Return a new `Collector`.
  `Integer`
  `reduce(Collection<TotalHitCountCollector> collectors)`
  Reduce the results of individual collectors into a meaningful result.

  ### Methods inherited from class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### TotalHitCountCollectorManager

    public TotalHitCountCollectorManager(IndexSearcher.LeafSlice[] leafSlices)
    Creates a new total hit count collector manager, providing the array of leaf slices that search targets, which can be retrieved via `IndexSearcher.getSlices()` for the searcher.
    Parameters:
      `leafSlices` - the slices that the searcher targets. Used to optimize the collection depending on whether segments have been partitioned into partitions or not.

- ## Method Details

  - ### newCollector

    public TotalHitCountCollector newCollector() throws IOException
    Description copied from interface: `CollectorManager`
    Return a new `Collector`. This must return a different instance on each call.
    Specified by:
      `newCollector` in interface `CollectorManager<TotalHitCountCollector,Integer>`
    Throws:
      `IOException`

  - ### reduce

    public Integer reduce(Collection<TotalHitCountCollector> collectors) throws IOException
    Description copied from interface: `CollectorManager`
    Reduce the results of individual collectors into a meaningful result. For instance a `TopDocsCollector` would compute the `top docs` of each collector and then merge them using `TopDocs.merge(int, TopDocs[])`. This method must be called after collection is finished on all provided collectors.
    Specified by:
      `reduce` in interface `CollectorManager<TotalHitCountCollector,Integer>`
    Throws:
      `IOException`