org.apache.lucene.search
Class IndexSearcher

java.lang.Object
  extended byorg.apache.lucene.search.Searcher
      extended byorg.apache.lucene.search.IndexSearcher
All Implemented Interfaces:
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(String path)
          Creates a searcher searching the index in the named directory.
 
Method Summary
 void close()
          Frees resources associated with this Searcher.
 Document doc(int i)
          For use by HitCollector implementations.
 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.
 
Methods inherited from class org.apache.lucene.search.Searcher
getSimilarity, 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(String path)
              throws IOException
Creates a searcher searching the index in the named directory.


IndexSearcher

public IndexSearcher(Directory directory)
              throws 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 IOException
Frees resources associated with this Searcher. Be careful not to call this method while you are still using objects like Hits.

Throws:
IOException

docFreq

public int docFreq(Term term)
            throws IOException
Expert: Returns the number of documents containing term. Called by search code to compute term weights.

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

doc

public Document doc(int i)
             throws IOException
For use by HitCollector implementations.

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

maxDoc

public int maxDoc()
           throws IOException
Expert: Returns one greater than the largest possible document number. Called by search code to compute term weights.

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

search

public TopDocs search(Query query,
                      Filter filter,
                      int nDocs)
               throws IOException
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:
IOException

search

public void search(Query query,
                   Filter filter,
                   HitCollector results)
            throws IOException
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:
IOException

rewrite

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

Throws:
IOException

explain

public Explanation explain(Query query,
                           int doc)
                    throws 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:
IOException


Copyright © 2000-2003 Apache Software Foundation. All Rights Reserved.