public class

MultiSearcher

extends Searcher
java.lang.Object
   ↳ org.apache.lucene.search.Searcher
     ↳ org.apache.lucene.search.MultiSearcher
Known Direct Subclasses

Class Overview

Implements search over a set of Searchables.

Applications usually need only call the inherited search(Query, int) or search(Query, Filter, int) methods.

Summary

Public Constructors
MultiSearcher(Searchable... searchables)
Creates a searcher which searches searchers.
Public Methods
void close()
Frees resources associated with this Searcher.
Document doc(int n)
Returns the stored fields of document i.
Document doc(int n, FieldSelector fieldSelector)
Get the Document at the nth position.
int docFreq(Term term)
Expert: Returns the number of documents containing term.
Explanation explain(Weight weight, int doc)
Expert: low-level implementation method Returns an Explanation that describes how doc scored against weight.
Searchable[] getSearchables()
Return the array of Searchables this searches.
int maxDoc()
Expert: Returns one greater than the largest possible document number.
Query rewrite(Query original)
Expert: called to re-write queries into primitive queries.
void search(Weight weight, Filter filter, Collector collector)
Lower-level search API.
TopDocs search(Weight weight, Filter filter, int nDocs)
Expert: Low-level search implementation.
TopFieldDocs search(Weight weight, Filter filter, int n, Sort sort)
Expert: Low-level search implementation with arbitrary sorting.
int subDoc(int n)
Returns the document number of document n within its sub-index.
int subSearcher(int n)
Returns index of the searcher for document n in the array used to construct this searcher.
Protected Methods
Weight createWeight(Query original)
Create weight in multiple index scenario.
int[] getStarts()
[Expand]
Inherited Methods
From class org.apache.lucene.search.Searcher
From class java.lang.Object
From interface java.io.Closeable
From interface org.apache.lucene.search.Searchable

Public Constructors

public MultiSearcher (Searchable... searchables)

Creates a searcher which searches searchers.

Throws
IOException

Public Methods

public void close ()

Frees resources associated with this Searcher. Be careful not to call this method while you are still using objects that reference this Searchable.

Throws
IOException

public Document doc (int n)

Returns the stored fields of document i.

public Document doc (int n, FieldSelector fieldSelector)

Get the Document at the nth position. The FieldSelector may be used to determine what Fields to load and how they should be loaded. NOTE: If the underlying Reader (more specifically, the underlying FieldsReader) is closed before the lazy Field is loaded an exception may be thrown. If you want the value of a lazy Field to be available after closing you must explicitly load it or fetch the Document again with a new loader.

Parameters
n Get the document at the nth position
fieldSelector The FieldSelector to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.
Returns
  • The stored fields of the Document at the nth position

public int docFreq (Term term)

Expert: Returns the number of documents containing term.

Throws
IOException

public Explanation explain (Weight weight, int doc)

Expert: low-level implementation method Returns an Explanation that describes how doc scored against weight.

This is intended to be used in developing Similarity implementations, and, for good performance, should not be displayed with every hit. Computing an explanation is as expensive as executing the query over the entire index.

Applications should call explain(Query, int).

Throws
IOException

public Searchable[] getSearchables ()

Return the array of Searchables this searches.

public int maxDoc ()

Expert: Returns one greater than the largest possible document number.

Throws
IOException

public Query rewrite (Query original)

Expert: called to re-write queries into primitive queries.

Throws
IOException

public void search (Weight weight, Filter filter, Collector collector)

Lower-level search API.

collect(int) is called for every document.
Collector-based access to remote indexes is discouraged.

Applications should only use this if they need all of the matching documents. The high-level search API (search(Query, int)) is usually more efficient, as it skips non-high-scoring hits.

Parameters
weight to match documents
filter if non-null, used to permit documents to be collected.
collector to receive hits
Throws
IOException

public TopDocs search (Weight weight, Filter filter, int nDocs)

Expert: Low-level search implementation. Finds the top n hits for query, applying filter if non-null.

Applications should usually call search(Query, int) or search(Query, Filter, int) instead.

Throws
IOException

public TopFieldDocs search (Weight weight, Filter filter, int n, Sort sort)

Expert: Low-level search implementation with arbitrary sorting. Finds the top n hits for query, applying filter if non-null, and sorting the hits by the criteria in sort.

Applications should usually call search(Query, Filter, int, Sort) instead.

Throws
IOException

public int subDoc (int n)

Returns the document number of document n within its sub-index.

public int subSearcher (int n)

Returns index of the searcher for document n in the array used to construct this searcher.

Protected Methods

protected Weight createWeight (Query original)

Create weight in multiple index scenario. Distributed query processing is done in the following steps: 1. rewrite query 2. extract necessary terms 3. collect dfs for these terms from the Searchables 4. create query weight using aggregate dfs. 5. distribute that weight to Searchables 6. merge results Steps 1-4 are done here, 5+6 in the search() methods

Returns
  • rewritten queries
Throws
IOException

protected int[] getStarts ()