org.apache.lucene.search
Class IndexSearcher

java.lang.Object
  extended byorg.apache.lucene.search.Searcher
      extended byorg.apache.lucene.search.IndexSearcher
All Implemented Interfaces:
java.rmi.Remote, Searchable

public class IndexSearcher
extends Searcher

Implements search over a single IndexReader.

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


Constructor Summary
IndexSearcher(Directory directory)
          Creates a searcher searching the index in the provided directory.
IndexSearcher(IndexReader r)
          Creates a searcher searching the provided index.
IndexSearcher(java.lang.String path)
          Creates a searcher searching the index in the named directory.
 
Method Summary
 void close()
          Note that the underlying IndexReader is not closed, if IndexSearcher was constructed with IndexSearcher(IndexReader r).
 Document doc(int i)
          Expert: Returns the stored fields of document i.
 int docFreq(Term term)
          Expert: Returns the number of documents containing term.
 Explanation explain(Query query, int doc)
          Returns an Explanation that describes how doc scored against query.
 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(Query query, Filter filter, HitCollector results)
          Lower-level search API.
 TopDocs search(Query query, Filter filter, int nDocs)
          Expert: Low-level search implementation.
 TopFieldDocs search(Query query, Filter filter, int nDocs, Sort sort)
          Expert: Low-level search implementation with arbitrary sorting.
 
Methods inherited from class org.apache.lucene.search.Searcher
getSimilarity, search, search, search, search, search, setSimilarity
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

IndexSearcher

public IndexSearcher(java.lang.String path)
              throws java.io.IOException
Creates a searcher searching the index in the named directory.


IndexSearcher

public IndexSearcher(Directory directory)
              throws java.io.IOException
Creates a searcher searching the index in the provided directory.


IndexSearcher

public IndexSearcher(IndexReader r)
Creates a searcher searching the provided index.

Method Detail

close

public void close()
           throws java.io.IOException
Note that the underlying IndexReader is not closed, if IndexSearcher was constructed with IndexSearcher(IndexReader r). If the IndexReader was supplied implicitly by specifying a directory, then the IndexReader gets closed.

Throws:
java.io.IOException

docFreq

public int docFreq(Term term)
            throws java.io.IOException
Description copied from interface: Searchable
Expert: Returns the number of documents containing term. Called by search code to compute term weights.

Throws:
java.io.IOException
See Also:
IndexReader.docFreq(Term).

doc

public Document doc(int i)
             throws java.io.IOException
Description copied from interface: Searchable
Expert: Returns the stored fields of document i. Called by HitCollector implementations.

Throws:
java.io.IOException
See Also:
IndexReader.document(int).

maxDoc

public int maxDoc()
           throws java.io.IOException
Description copied from interface: Searchable
Expert: Returns one greater than the largest possible document number. Called by search code to compute term weights.

Throws:
java.io.IOException
See Also:
IndexReader.maxDoc().

search

public TopDocs search(Query query,
                      Filter filter,
                      int nDocs)
               throws java.io.IOException
Description copied from interface: Searchable
Expert: Low-level search implementation. Finds the top n hits for query, applying filter if non-null.

Called by Hits.

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

Throws:
java.io.IOException

search

public TopFieldDocs search(Query query,
                           Filter filter,
                           int nDocs,
                           Sort sort)
                    throws java.io.IOException
Description copied from interface: Searchable
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 Searcher.search(Query,Filter,Sort) instead.

Throws:
java.io.IOException

search

public void search(Query query,
                   Filter filter,
                   HitCollector results)
            throws java.io.IOException
Description copied from interface: Searchable
Lower-level search API.

HitCollector.collect(int,float) is called for every non-zero scoring document.

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

Parameters:
query - to match documents
filter - if non-null, a bitset used to eliminate some documents
results - to receive hits
Throws:
java.io.IOException

rewrite

public Query rewrite(Query original)
              throws java.io.IOException
Description copied from interface: Searchable
Expert: called to re-write queries into primitive queries.

Throws:
java.io.IOException

explain

public Explanation explain(Query query,
                           int doc)
                    throws java.io.IOException
Description copied from interface: Searchable
Returns an Explanation that describes how doc scored against query.

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.

Throws:
java.io.IOException


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