org.apache.lucene.search
Class DelayCloseIndexSearcher

java.lang.Object
  org.apache.lucene.search.Searcher
      org.apache.lucene.search.IndexSearcher
          org.apache.lucene.search.DelayCloseIndexSearcher

All Implemented Interfaces:

java.rmi.Remote, org.apache.lucene.search.Searchable

public class DelayCloseIndexSearcher

extends org.apache.lucene.search.IndexSearcher

Implements search over a single IndexReader, but remains open even if close() is called. This way it can be shared by multiple objects that need to search the index without being aware of the keep-the-index-open-until-it-changes logic.

Basic use (works, but can slow all searcher while opening a new Searcher instance:

 class SearcherFactory {
     SearcherFactory(Directory directory){
         currentSearcher=new DelayCloseIndexSearcher(directory);
     }
 

     public synchronized IndexSearcher createSearcher() {
         if (!currentSearcher.isCurrent()) {
             currentSearcher.closeWhenDone();
             currentSearcher=new DelayCloseIndexSearcher(directory);
         }
 

         currentSearcher.open();
         return currentSearcher;
     }
 

     void synchronized close() {
         currentSearcher.closeWhenDone();
     }
 

     private final Directory directory;
 

     private DelayCloseIndexSearcher currentSearcher;
 }
 

Objects that need to search the index do the following:

 //searcherFactory is created once at startup
 

 IndexSearcher indexSearcher=searcherFactory.createSearcher();
 Hits hist=indexSearcher.search(query, filter, sort);
 ... // handle results
 indexSearcher.close();
 

 // when the application shuts down
 searcherFactory.close();
 

Author:

Luc Vanlerberghe

Constructor Summary

DelayCloseIndexSearcher(org.apache.lucene.store.Directory directory)
Creates a DelayCloseIndexSearcher searching the index in the provided directory..

DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader indexReader)
Creates a DelayCloseIndexSearcher searching the index using the provided Reader

DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader indexReader, org.apache.lucene.store.Directory directory)
Deprecated. Use DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader) instead

DelayCloseIndexSearcher(java.lang.String string)

Method Summary

void	close() Should be called once for every call to open().
void	closeWhenDone() Signals that this instance may really close when all open() calls have been balanced with a call to close().
boolean	isClosed() Returns wether the underlying IndexSearcher has really been closed.
boolean	isCurrent() Returns whether the underlying IndexSearcher instance still works on a current version of the index.
void	open() This should be called whenever this instances is passed as a new IndexSearcher.

Methods inherited from class org.apache.lucene.search.IndexSearcher

doc, doc, docFreq, explain, getIndexReader, maxDoc, rewrite, search, search, search

Methods inherited from class org.apache.lucene.search.Searcher

createWeight, docFreqs, explain, getSimilarity, search, search, search, 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

DelayCloseIndexSearcher

public DelayCloseIndexSearcher(java.lang.String string)
                        throws java.io.IOException

DelayCloseIndexSearcher

public DelayCloseIndexSearcher(org.apache.lucene.store.Directory directory)
                        throws java.io.IOException

Creates a DelayCloseIndexSearcher searching the index in the provided directory..

Parameters:

directory - containing the index.

Throws:

java.io.IOException - if an I/O error occurs.

DelayCloseIndexSearcher

public DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader indexReader)
                        throws java.io.IOException

Creates a DelayCloseIndexSearcher searching the index using the provided Reader

Parameters:

indexReader - Reader to use for opening the searcher

Throws:

java.io.IOException - if an I/O error occurs

DelayCloseIndexSearcher

public DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader indexReader,
                               org.apache.lucene.store.Directory directory)
                        throws java.io.IOException

Deprecated. Use DelayCloseIndexSearcher(org.apache.lucene.index.IndexReader) instead

Parameters:

indexReader - The indexReader to use for the searcher

directory - No longer in use

Throws:

java.io.IOException - If there's a problem opening the underlying searcher

Method Detail

open

public void open()

This should be called whenever this instances is passed as a new IndexSearcher. Only when each call to open() is balanced with a call to close(), and closeWhenDone has been called, will super.close() be called.

closeWhenDone

public void closeWhenDone()
                   throws java.io.IOException

Signals that this instance may really close when all open() calls have been balanced with a call to close().

Throws:

java.io.IOException - if an I/O error occurs.

isCurrent

public boolean isCurrent()
                  throws java.io.IOException

Returns whether the underlying IndexSearcher instance still works on a current version of the index. If it returns false, closeWhenDone() should be called and another instance created to handle further search requests.

Returns:

whether the underlying IndexSearcher instance still works on a current version of the index

Throws:

java.io.IOException - if an I/O error occurs.

isClosed

public boolean isClosed()

Returns wether the underlying IndexSearcher has really been closed. If it is true, this instance can no longer be used.

Returns:

whether the underlying IndexSearcher has really been closed.

close

public void close()
           throws java.io.IOException

Should be called once for every call to open(). If the usageCount drops to zero and closeWhenDone() was called, super.close() will be called.

Throws:

java.io.IOException - if an I/O error occurs.