com.epimorphics.server.indexers

Class LuceneIndex

java.lang.Object

com.epimorphics.server.core.ServiceBase

com.epimorphics.server.indexers.LuceneIndex

All Implemented Interfaces:

Indexer, Service, Shutdown

public class LuceneIndex
extends ServiceBase
implements Indexer, Service, Shutdown

Text index for entities in a store.

An entity is any resource in the graph that has one or more explicit types.

There are three types of index fields supported:

• label fields - which are indexed as free text (i.e. analyzed)
• value fields - which are indexed as node values
• facet fields - which are indexed to support faceted search

Node values are either resources (uses shared ByteRef of the URI), numbers (any numeric literal which fits in a long is indexed as a Long) or literal (which are indexed as non-shared lexical forms).

Configuration parameters are:

• location - directory where the index should be built and stored
• config - RDF file giving the index configuration
• commitWindow - time in sec to wait after a change before committing, default 0

Author:

Dave Reynolds

Field Summary

Fields

Modifier and Type	Field and Description
protected int	batchDepth
protected static Timer	cleanupTimer
static String	COMMIT_PARAM
protected boolean	commitScheduled
protected int	commitWindow
static String	CONFIG_PARAM
protected static int	DEFAULT_COMMIT_WINDOW
static String	FIELD_GRAPH
static String	FIELD_LABEL
static String	FIELD_URI
protected Set<com.hp.hpl.jena.rdf.model.Resource>	ignoreProps
protected boolean	indexAll
protected org.apache.lucene.store.Directory	indexDir
protected Set<com.hp.hpl.jena.rdf.model.Resource>	labelOnlyProps
protected Set<com.hp.hpl.jena.rdf.model.Resource>	labelProps
static String	LOCATION_PARAM
protected static org.apache.lucene.search.SearcherManager	searchManager
protected Set<com.hp.hpl.jena.rdf.model.Resource>	valueProps
protected static org.apache.lucene.index.IndexWriter	writer

Fields inherited from class com.epimorphics.server.core.ServiceBase

config

Constructor Summary

Constructors

Constructor and Description
LuceneIndex()

Method Summary

Methods

Modifier and Type	Method and Description
void	addGraph(String graphname, com.hp.hpl.jena.rdf.model.Model graph)
void	deleteGraph(String graphname)
protected void	doCommit()
void	endBatch() Since the end up an update batch.
protected org.apache.lucene.index.IndexWriter	getIndexWriter()
protected void	indexGraph(String graphname, com.hp.hpl.jena.rdf.model.Model graph, boolean update)
void	init(Map<String,String> config, javax.servlet.ServletContext context)
protected void	requestCommit()
protected void	scheduleCommit()
LuceneResult[]	search(org.apache.lucene.search.Query query, int offset, int maxResults) Search the index for entities which match a lucene query.
LuceneResult[]	search(String query, int offset, int maxResults) Search the index for entities which match a lucene query using the standard lucene synta.
void	shutdown()
void	startBatch() Signal an indexer that a batch of changes is starting, this may be used to optimize commit cycles.
void	updateGraph(String graphname, com.hp.hpl.jena.rdf.model.Model graph)

Methods inherited from class com.epimorphics.server.core.ServiceBase

getFileParam, getNamedService, getRequiredFileParam, getRequiredIntParam, getRequiredParam, postInit, postPostInit

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.epimorphics.server.core.Service

postInit, postPostInit

Field Detail

LOCATION_PARAM

public static final String LOCATION_PARAM

See Also:

Constant Field Values

CONFIG_PARAM

public static final String CONFIG_PARAM

See Also:

Constant Field Values

COMMIT_PARAM

public static final String COMMIT_PARAM

See Also:

Constant Field Values

FIELD_URI

public static final String FIELD_URI

See Also:

Constant Field Values

FIELD_GRAPH

public static final String FIELD_GRAPH

See Also:

Constant Field Values

FIELD_LABEL

public static final String FIELD_LABEL

See Also:

Constant Field Values

DEFAULT_COMMIT_WINDOW

protected static int DEFAULT_COMMIT_WINDOW

indexAll

protected boolean indexAll

labelProps

protected Set<com.hp.hpl.jena.rdf.model.Resource> labelProps

labelOnlyProps

protected Set<com.hp.hpl.jena.rdf.model.Resource> labelOnlyProps

ignoreProps

protected Set<com.hp.hpl.jena.rdf.model.Resource> ignoreProps

valueProps

protected Set<com.hp.hpl.jena.rdf.model.Resource> valueProps

indexDir

protected org.apache.lucene.store.Directory indexDir

writer

protected static org.apache.lucene.index.IndexWriter writer

searchManager

protected static org.apache.lucene.search.SearcherManager searchManager

batchDepth

protected int batchDepth

commitWindow

protected int commitWindow

commitScheduled

protected boolean commitScheduled

cleanupTimer

protected static Timer cleanupTimer

Constructor Detail

LuceneIndex

public LuceneIndex()

Method Detail

init

public void init(Map<String,String> config,
        javax.servlet.ServletContext context)

Specified by:

init in interface Service

Overrides:

init in class ServiceBase

addGraph

public void addGraph(String graphname,
            com.hp.hpl.jena.rdf.model.Model graph)

Specified by:

addGraph in interface Indexer

updateGraph

public void updateGraph(String graphname,
               com.hp.hpl.jena.rdf.model.Model graph)

Specified by:

updateGraph in interface Indexer

deleteGraph

public void deleteGraph(String graphname)

Specified by:

deleteGraph in interface Indexer

search

public LuceneResult[] search(org.apache.lucene.search.Query query,
                    int offset,
                    int maxResults)

Search the index for entities which match a lucene query. Use field "label" for searching on lables (e.g. PhraseQuery or TermQuery).

search

public LuceneResult[] search(String query,
                    int offset,
                    int maxResults)

Search the index for entities which match a lucene query using the standard lucene synta. Fields names indexed from the RDF will be URIs and so characters like ':' and '/' need to be escaped in the query string.

indexGraph

protected void indexGraph(String graphname,
              com.hp.hpl.jena.rdf.model.Model graph,
              boolean update)

getIndexWriter

protected org.apache.lucene.index.IndexWriter getIndexWriter()

startBatch

public void startBatch()

Description copied from interface: Indexer

Signal an indexer that a batch of changes is starting, this may be used to optimize commit cycles. No formal transaction semantics implied, is that needed here

Specified by:

startBatch in interface Indexer

endBatch

public void endBatch()

Description copied from interface: Indexer

Since the end up an update batch.

Specified by:

endBatch in interface Indexer

requestCommit

protected void requestCommit()
                      throws IOException

Throws:

IOException

scheduleCommit

protected void scheduleCommit()

doCommit

protected void doCommit()

shutdown

public void shutdown()

Specified by:

shutdown in interface Shutdown