org.apache.jackrabbit.core.query.lucene
Class MultiIndex

java.lang.Object
  org.apache.jackrabbit.core.query.lucene.MultiIndex

public class MultiIndex

extends Object

A MultiIndex consists of a VolatileIndex and multiple PersistentIndexes. The goal is to keep most parts of the index open with index readers and write new index data to the volatile index. When the volatile index reaches a certain size (see SearchIndex.setMinMergeDocs(int)) a new persistent index is created with the index data from the volatile index, the same happens when the volatile index has been idle for some time (see SearchIndex.setVolatileIdleTime(int)). The new persistent index is then added to the list of already existing persistent indexes. Further operations on the new persistent index will however only require an IndexReader which serves for queries but also for delete operations on the index.

The persistent indexes are merged from time to time. The merge behaviour is configurable using the methods: SearchIndex.setMaxMergeDocs(int), SearchIndex.setMergeFactor(int) and SearchIndex.setMinMergeDocs(int). For detailed description of the configuration parameters see also the lucene IndexWriter class.

This class is thread-safe.

Note on implementation: Multiple modifying threads are synchronized on a MultiIndex instance itself. Sychronization between a modifying thread and reader threads is done using #updateMonitor and #updateInProgress.

Nested Class Summary

static class

MultiIndex.Action Defines an action on an MultiIndex.

Method Summary

org.apache.lucene.index.IndexReader

getIndexReader() Returns an read-only IndexReader that spans alls indexes of this MultiIndex.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getIndexReader

public org.apache.lucene.index.IndexReader getIndexReader()
                                                   throws IOException

Returns an read-only IndexReader that spans alls indexes of this MultiIndex.

Returns:

an IndexReader.

Throws:

IOException - if an error occurs constructing the IndexReader.