org.apache.lucene.search

Interface CollectorManager<C extends Collector,T>

All Known Implementing Classes:

MultiCollectorManager

public interface CollectorManager<C extends Collector,T>

A manager of collectors. This class is useful to parallelize execution of search requests and has two main methods:

• newCollector() which must return a NEW collector which will be used to collect a certain set of leaves.
• reduce(Collection) which will be used to reduce the results of individual collections into a meaningful result. This method is only called after all leaves have been fully collected.

See Also:

IndexSearcher.search(Query, CollectorManager)

WARNING: This API is experimental and might change in incompatible ways in the next release.

Method Summary

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

Method Detail

newCollector

C newCollector()
        throws IOException

Return a new Collector. This must return a different instance on each call.

Throws:

IOException

reduce

T reduce(Collection<C> collectors)
  throws IOException

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.

Throws:

IOException