org.neo4j.index.lucene
Class LuceneIndexService

java.lang.Object
  org.neo4j.index.impl.GenericIndexService
      org.neo4j.index.lucene.LuceneIndexService

All Implemented Interfaces:

IndexService

Direct Known Subclasses:

LuceneFulltextIndexService

public class LuceneIndexService
extends org.neo4j.index.impl.GenericIndexService

An implementation of IndexService which uses Lucene as backend. Additional features to IndexService is:

• enableCache(String, int) will enable a LRU cache for the specific key and will boost performance in performance-critical areas.
• getNodes(String, Object, Sort) where you can pass in a Sort option to control in which order Lucene returns the results
• setLazySearchResultThreshold(int) will control the threshold for when a search result is considered big enough to be returned as a lazy iteration, making getNodes(String, Object) return very fast, but skips caching

See more information at http://wiki.neo4j.org/content/Indexing_with_IndexService

Field Summary

static int	DEFAULT_LAZY_SEARCH_RESULT_THRESHOLD The default value for getLazySearchResultThreshold()
protected static String	DIR_NAME
protected static String	DOC_ID_KEY
protected static String	DOC_INDEX_KEY

Constructor Summary

LuceneIndexService(org.neo4j.graphdb.GraphDatabaseService graphDb)

Method Summary

void	enableCache(String key, int maxNumberOfCachedEntries) Enables an LRU cache for a specific index (specified by key) so that the maxNumberOfCachedEntries number of results found with getNodes(String, Object) are cached for faster consecutive lookups.
protected org.apache.lucene.search.Query	formQuery(String key, Object value, Object matching)
protected Class<? extends LuceneDataSource>	getDataSourceClass()
protected String	getDirName()
Integer	getEnabledCacheSize(String key) Returns the enabled LRU cache size for key.
int	getLazySearchResultThreshold() Returns the threshold for when a result is considered big enough to skip cache and be returned as a fully lazy iterator so that getNodes(String, Object) will return very fast and all the reading and fetching of nodes is done lazily before each step in the iteration of the returned result.
IndexHits<org.neo4j.graphdb.Node>	getNodes(String key, Object value) Returns all nodes indexed with key and value.
protected IndexHits<org.neo4j.graphdb.Node>	getNodes(String key, Object value, Object matching, org.apache.lucene.search.Sort sortingOrNull) Just like getNodes(String, Object), but with sorted result.
IndexHits<org.neo4j.graphdb.Node>	getNodes(String key, Object value, org.apache.lucene.search.Sort sortingOrNull) Returns hits from the index (see getNodes(String, Object)).
IndexHits<org.neo4j.graphdb.Node>	getNodesExactMatch(String key, Object value) A method for calling getNodes(String, Object) using exact matching.
org.neo4j.graphdb.Node	getSingleNode(String key, Object value) Returns a single node indexed with associated with key and value.
protected org.neo4j.graphdb.Node	getSingleNode(String key, Object value, Object matching)
org.neo4j.graphdb.Node	getSingleNodeExactMatch(String key, Object value) A method for calling getSingleNode(String, Object) using exact matching.
protected byte[]	getXaResourceId()
void	index(org.neo4j.graphdb.Node node, String key, Object value) Index node with key and value.
protected void	indexThisTx(org.neo4j.graphdb.Node node, String key, Object value)
protected Iterator<org.neo4j.graphdb.Node>	instantiateIdToNodeIterator(Iterator<Long> ids)
void	removeIndex(org.neo4j.graphdb.Node node, String key) Dissociates a node from all indexed values for the given key.
void	removeIndex(String key) Dissociates all key-value pairs which key is part of, i.e.
protected void	removeIndexThisTx(org.neo4j.graphdb.Node node, String key, Object value)
void	setLazySearchResultThreshold(int numberOfHitsBeforeLazyLoading) Sets the threshold for when a result is considered big enough to skip cache and be returned as a fully lazy iterator so that getNodes(String, Object) will return very fast and all the reading and fetching of nodes is done lazily before each step in the iteration of the returned result.
void	shutdown() Shuts down the index service.

Methods inherited from class org.neo4j.index.impl.GenericIndexService

beginTx, getGraphDb, removeIndex

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_LAZY_SEARCH_RESULT_THRESHOLD

public static final int DEFAULT_LAZY_SEARCH_RESULT_THRESHOLD

The default value for getLazySearchResultThreshold()

See Also:

Constant Field Values

DOC_ID_KEY

protected static final String DOC_ID_KEY

See Also:

Constant Field Values

DOC_INDEX_KEY

protected static final String DOC_INDEX_KEY

See Also:

Constant Field Values

DIR_NAME

protected static final String DIR_NAME

See Also:

Constant Field Values

Constructor Detail

LuceneIndexService

public LuceneIndexService(org.neo4j.graphdb.GraphDatabaseService graphDb)

Parameters:

graphDb - the GraphDatabaseService to use.

Method Detail

getDataSourceClass

protected Class<? extends LuceneDataSource> getDataSourceClass()

getDirName

protected String getDirName()

getXaResourceId

protected byte[] getXaResourceId()

enableCache

public void enableCache(String key,
                        int maxNumberOfCachedEntries)

Enables an LRU cache for a specific index (specified by key) so that the maxNumberOfCachedEntries number of results found with getNodes(String, Object) are cached for faster consecutive lookups. It's preferred to enable cache at construction time.

Parameters:

key - the index to enable cache for.

maxNumberOfCachedEntries - the max size of the cache before old ones are flushed from the cache.

getEnabledCacheSize

public Integer getEnabledCacheSize(String key)

Returns the enabled LRU cache size for key. Cache is enabled using enableCache(String, int). If cache hasn't been enabled for key then null is returned.

Parameters:

key - the key to get the enabled cache size for.

Returns:

the max cache size for key or null if not enabled for that key.

setLazySearchResultThreshold

public void setLazySearchResultThreshold(int numberOfHitsBeforeLazyLoading)

Sets the threshold for when a result is considered big enough to skip cache and be returned as a fully lazy iterator so that getNodes(String, Object) will return very fast and all the reading and fetching of nodes is done lazily before each step in the iteration of the returned result. The default value is DEFAULT_LAZY_SEARCH_RESULT_THRESHOLD.

Parameters:

numberOfHitsBeforeLazyLoading - the threshold where results which are bigger than that threshold becomes lazy.

getLazySearchResultThreshold

public int getLazySearchResultThreshold()

Returns the threshold for when a result is considered big enough to skip cache and be returned as a fully lazy iterator so that getNodes(String, Object) will return very fast and all the reading and fetching of nodes is done lazily before each step in the iteration of the returned result. The default value is DEFAULT_LAZY_SEARCH_RESULT_THRESHOLD.

Returns:

the threshold for when a result is considered big enough to be returned as a lazy iteration.

index

public void index(org.neo4j.graphdb.Node node,
                  String key,
                  Object value)

Index node with key and value. A node can be associated with any number of key-value pairs.

Note about updating an index: If you've indexed a value from a property on a Node and that value gets updated, you'll have to remove the old value in addition to indexing the new value, else both values (the new and the old) will be indexed for that node.

When deleting a Node, application should remove the index entries for the node as well, to keep the index consistent with the node space.

Note that this implementation will cast objects given as the value to String.

Specified by:

index in interface IndexService

Overrides:

index in class org.neo4j.index.impl.GenericIndexService

Parameters:

node - node to index

key - the key in the key-value pair to associate with node.

value - the value in the key-value pair to associate with node.

indexThisTx

protected void indexThisTx(org.neo4j.graphdb.Node node,
                           String key,
                           Object value)

Specified by:

indexThisTx in class org.neo4j.index.impl.GenericIndexService

getNodes

public IndexHits<org.neo4j.graphdb.Node> getNodes(String key,
                                                  Object value)

Returns all nodes indexed with key and value.

Note that this implementation will cast objects given as the value to String.

Parameters:

key - the key for index

value - the value for index

Returns:

nodes that have been indexed with key and value

getNodes

public IndexHits<org.neo4j.graphdb.Node> getNodes(String key,
                                                  Object value,
                                                  org.apache.lucene.search.Sort sortingOrNull)

Returns hits from the index (see getNodes(String, Object)). The result is sorted using sortingOrNull.

Parameters:

key - the index to search in.

value - the value to match hits for.

sortingOrNull - how the result should be sorted.

Returns:

the (sorted) results from this index lookup.

getNodesExactMatch

public IndexHits<org.neo4j.graphdb.Node> getNodesExactMatch(String key,
                                                            Object value)

A method for calling getNodes(String, Object) using exact matching. For this class it's equivalent to calling getNodes(String, Object), but for subclasses, such as LuceneFulltextIndexService it is useful for it to be able to do queries with exact matching, even though it's a fulltext index.

Parameters:

key - the index to search in.

value - the value to match hits for.

Returns:

nodes that have been indexed with key and value

getNodes

protected IndexHits<org.neo4j.graphdb.Node> getNodes(String key,
                                                     Object value,
                                                     Object matching,
                                                     org.apache.lucene.search.Sort sortingOrNull)

Just like getNodes(String, Object), but with sorted result.

Parameters:

key - the index to query.

value - the value to query for.

sortingOrNull - lucene sorting behaviour for the result. Ignored if null.

Returns:

nodes that has been indexed with key and value, optionally sorted with sortingOrNull.

instantiateIdToNodeIterator

protected Iterator<org.neo4j.graphdb.Node> instantiateIdToNodeIterator(Iterator<Long> ids)

formQuery

protected org.apache.lucene.search.Query formQuery(String key,
                                                   Object value,
                                                   Object matching)

Parameters:

key - the key

value - the value

matching - an object describing what kind of matching to do. The type this object is is solely up to the implementation.

Returns:

the Query formed from key/value.

getSingleNodeExactMatch

public org.neo4j.graphdb.Node getSingleNodeExactMatch(String key,
                                                      Object value)

A method for calling getSingleNode(String, Object) using exact matching. For this class it's equivalent to calling getSingleNode(String, Object), but for subclasses, such as LuceneFulltextIndexService it is useful for it to be able to do queries with exact matching, even though it's a fulltext index.

Parameters:

key - the index to search in.

value - the value to match hits for.

Returns:

the single node for the query, or null if no hit found. If more than one hit was found a RuntimeException is thrown.

getSingleNode

public org.neo4j.graphdb.Node getSingleNode(String key,
                                            Object value)

Description copied from interface: IndexService

Returns a single node indexed with associated with key and value. If no such node exist null is returned. If more then one node is found a runtime exception is thrown.

Parameters:

key - the key for index

value - the value for index

Returns:

node that has been indexed with key and value or null

getSingleNode

protected org.neo4j.graphdb.Node getSingleNode(String key,
                                               Object value,
                                               Object matching)

removeIndexThisTx

protected void removeIndexThisTx(org.neo4j.graphdb.Node node,
                                 String key,
                                 Object value)

Specified by:

removeIndexThisTx in class org.neo4j.index.impl.GenericIndexService

shutdown

public void shutdown()

Description copied from interface: IndexService

Shuts down the index service. After this method has been invoked any following method invocation on this instance is invalid.

Specified by:

shutdown in interface IndexService

Overrides:

shutdown in class org.neo4j.index.impl.GenericIndexService

removeIndex

public void removeIndex(org.neo4j.graphdb.Node node,
                        String key)

Description copied from interface: IndexService

Dissociates a node from all indexed values for the given key. If no such association exists this method silently returns. Implementations may choose to not implement this method and should in such a case throw UnsupportedOperationException.

Parameters:

node - the node to dissociate from all indexed values for the given key.

key - the key in the key-value pairs to remove.

removeIndex

public void removeIndex(String key)

Description copied from interface: IndexService

Dissociates all key-value pairs which key is part of, i.e. clearing the an entire index key is cleared. Implementations may choose to not implement this method and should in such a case throw UnsupportedOperationException.

Parameters:

key - the index to clear.