com.orientechnologies.orient.core.index

Interface OIndex<T>

All Superinterfaces:

Comparable<OIndex<T>>

All Known Subinterfaces:

OIndexInternal<T>

All Known Implementing Classes:

OChainedIndexProxy, OIndexAbstract, OIndexAbstractDelegate, OIndexDictionary, OIndexFullText, OIndexMultiValues, OIndexNotUnique, OIndexOneValue, OIndexRemote, OIndexRemoteMultiValue, OIndexRemoteOneValue, OIndexTxAware, OIndexTxAwareDictionary, OIndexTxAwareMultiValue, OIndexTxAwareOneValue, OIndexUnique, OLuceneFullTextIndex, OLuceneIndexNotUnique, OLuceneSpatialIndex

public interface OIndex<T>
extends Comparable<OIndex<T>>

Basic interface to handle index.

Author:

Luca Garulli (l.garulli--(at)--orientdb.com)

Field Summary

Fields

Modifier and Type	Field and Description
static String	MERGE_KEYS

Method Summary

Modifier and Type	Method and Description
OIndex<T>	clear() Clears the index removing all the entries in one shot.
boolean	contains(Object iKey) Tells if a key is contained in the index.
long	count(Object iKey) Counts the entries for the key.
OIndex<T>	create(String name, OIndexDefinition indexDefinition, String clusterIndexName, Set<String> clustersToIndex, boolean rebuild, OProgressListener progressListener) Creates the index.
OIndexCursor	cursor()
OIndex<T>	delete() Delete the index.
OIndexCursor	descCursor()
void	flush() Flushes in-memory changes to disk.
T	get(Object iKey) Gets the set of records associated with the passed key.
String	getAlgorithm() Returns the engine of the index as string.
Set<String>	getClusters() Returns Names of clusters that will be indexed.
ODocument	getConfiguration() Returns the index configuration.
String	getDatabaseName()
OIndexDefinition	getDefinition()
Object	getFirstKey()
int	getIndexId()
OIndexInternal<T>	getInternal() Returns the internal index used.
long	getKeySize()
OType[]	getKeyTypes() Types of the keys that index can accept, if index contains composite key, list of types of elements from which this index consist will be returned, otherwise single element (key type obviously) will be returned.
Object	getLastKey()
ODocument	getMetadata()
String	getName() Returns the index name.
long	getRebuildVersion() Returns amount of times when index was rebuilt since storage was opened.
long	getSize()
String	getType() Returns the type of the index as string.
int	getVersion() Returns binary format version for this index.
boolean	isAutomatic() Tells if the index is automatic.
boolean	isRebuilding()
boolean	isUnique()
OIndexCursor	iterateEntries(Collection<?> keys, boolean ascSortOrder) Returns cursor which presents data associated with passed in keys.
OIndexCursor	iterateEntriesBetween(Object fromKey, boolean fromInclusive, Object toKey, boolean toInclusive, boolean ascOrder) Returns cursor which presents subset of index data between passed in keys.
OIndexCursor	iterateEntriesMajor(Object fromKey, boolean fromInclusive, boolean ascOrder) Returns cursor which presents subset of data which associated with key which is greater than passed in key.
OIndexCursor	iterateEntriesMinor(Object toKey, boolean toInclusive, boolean ascOrder) Returns cursor which presents subset of data which associated with key which is less than passed in key.
OIndexKeyCursor	keyCursor()
OIndex<T>	put(Object iKey, OIdentifiable iValue) Inserts a new entry in the index.
long	rebuild() Rebuilds an automatic index.
long	rebuild(OProgressListener iProgressListener) Populate the index with all the existent records.
boolean	remove(Object key) Removes an entry by its key.
boolean	remove(Object iKey, OIdentifiable iRID) Removes an entry by its key and value.
boolean	supportsOrderedIterations()

Methods inherited from interface java.lang.Comparable

compareTo

Field Detail

MERGE_KEYS

static final String MERGE_KEYS

See Also:

Constant Field Values

Method Detail

create

OIndex<T> create(String name,
                 OIndexDefinition indexDefinition,
                 String clusterIndexName,
                 Set<String> clustersToIndex,
                 boolean rebuild,
                 OProgressListener progressListener)

Creates the index.

Parameters:

name -

clusterIndexName - Cluster name where to place the TreeMap

clustersToIndex -

rebuild -

progressListener -

getDatabaseName

String getDatabaseName()

getKeyTypes

OType[] getKeyTypes()

Types of the keys that index can accept, if index contains composite key, list of types of elements from which this index consist will be returned, otherwise single element (key type obviously) will be returned.

get

T get(Object iKey)

Gets the set of records associated with the passed key.

Parameters:

iKey - The key to search

Returns:

The Record set if found, otherwise an empty Set

contains

boolean contains(Object iKey)

Tells if a key is contained in the index.

Parameters:

iKey - The key to search

Returns:

True if the key is contained, otherwise false

put

OIndex<T> put(Object iKey,
              OIdentifiable iValue)

Inserts a new entry in the index. The behaviour depends by the index implementation.

Parameters:

iKey - Entry's key

iValue - Entry's value as OIdentifiable instance

Returns:

The index instance itself to allow in chain calls

remove

boolean remove(Object key)

Removes an entry by its key.

Parameters:

key - The entry's key to remove

Returns:

True if the entry has been found and removed, otherwise false

remove

boolean remove(Object iKey,
               OIdentifiable iRID)

Removes an entry by its key and value.

Parameters:

iKey - The entry's key to remove

Returns:

True if the entry has been found and removed, otherwise false

clear

OIndex<T> clear()

Clears the index removing all the entries in one shot.

Returns:

The index instance itself to allow in chain calls

getSize

long getSize()

Returns:

number of entries in the index.

count

long count(Object iKey)

Counts the entries for the key.

getKeySize

long getKeySize()

Returns:

Number of keys in index

flush

void flush()

Flushes in-memory changes to disk.

delete

OIndex<T> delete()

Delete the index.

Returns:

The index instance itself to allow in chain calls

getName

String getName()

Returns the index name.

Returns:

The name of the index

getType

String getType()

Returns the type of the index as string.

getAlgorithm

String getAlgorithm()

Returns the engine of the index as string.

getVersion

int getVersion()

Returns binary format version for this index. Index format changes during system development but old formats are supported for binary compatibility. This method may be used to detect version of binary format which is used by current index and upgrade index to new one.

Returns:

Returns binary format version for this index if possible, otherwise -1.

isAutomatic

boolean isAutomatic()

Tells if the index is automatic. Automatic means it's maintained automatically by OrientDB. This is the case of indexes created against schema properties. Automatic indexes can always been rebuilt.

Returns:

True if the index is automatic, otherwise false

rebuild

long rebuild()

Rebuilds an automatic index.

Returns:

The number of entries rebuilt

See Also:

getRebuildVersion()

rebuild

long rebuild(OProgressListener iProgressListener)

Populate the index with all the existent records.

See Also:

getRebuildVersion()

getConfiguration

ODocument getConfiguration()

Returns the index configuration.

Returns:

An ODocument object containing all the index properties

getInternal

OIndexInternal<T> getInternal()

Returns the internal index used.

iterateEntries

OIndexCursor iterateEntries(Collection<?> keys,
                            boolean ascSortOrder)

Returns cursor which presents data associated with passed in keys.

Parameters:

keys - Keys data of which should be returned.

ascSortOrder - Flag which determines whether data iterated by cursor should be in ascending or descending order.

Returns:

cursor which presents data associated with passed in keys.

getDefinition

OIndexDefinition getDefinition()

getClusters

Set<String> getClusters()

Returns Names of clusters that will be indexed.

Returns:

Names of clusters that will be indexed.

iterateEntriesBetween

OIndexCursor iterateEntriesBetween(Object fromKey,
                                   boolean fromInclusive,
                                   Object toKey,
                                   boolean toInclusive,
                                   boolean ascOrder)

Returns cursor which presents subset of index data between passed in keys.

Parameters:

fromKey - Lower border of index data.

fromInclusive - Indicates whether lower border should be inclusive or exclusive.

toKey - Upper border of index data.

toInclusive - Indicates whether upper border should be inclusive or exclusive.

ascOrder - Flag which determines whether data iterated by cursor should be in ascending or descending order.

Returns:

Cursor which presents subset of index data between passed in keys.

iterateEntriesMajor

OIndexCursor iterateEntriesMajor(Object fromKey,
                                 boolean fromInclusive,
                                 boolean ascOrder)

Returns cursor which presents subset of data which associated with key which is greater than passed in key.

Parameters:

fromKey - Lower border of index data.

fromInclusive - Indicates whether lower border should be inclusive or exclusive.

ascOrder - Flag which determines whether data iterated by cursor should be in ascending or descending order.

Returns:

cursor which presents subset of data which associated with key which is greater than passed in key.

iterateEntriesMinor

OIndexCursor iterateEntriesMinor(Object toKey,
                                 boolean toInclusive,
                                 boolean ascOrder)

Returns cursor which presents subset of data which associated with key which is less than passed in key.

Parameters:

toKey - Upper border of index data.

toInclusive - Indicates Indicates whether upper border should be inclusive or exclusive.

ascOrder - Flag which determines whether data iterated by cursor should be in ascending or descending order.

Returns:

cursor which presents subset of data which associated with key which is less than passed in key.

cursor

OIndexCursor cursor()

descCursor

OIndexCursor descCursor()

keyCursor

OIndexKeyCursor keyCursor()

getMetadata

ODocument getMetadata()

supportsOrderedIterations

boolean supportsOrderedIterations()

getRebuildVersion

long getRebuildVersion()

Returns amount of times when index was rebuilt since storage was opened.

It is used to support so called "live index rebuild" feature.

Value of this version is increased every time when index is going to be rebuild. So if two sequential calls of this method return different numbers it means that index at least started to rebuild itself.

If you use indexes to increase speed of fetching data from database you should follow following workflow:

1. Read index rebuild version.
2. Check index rebuild flag isRebuilding(), if it is true, do not use index and fetch data directly from database clusters.
3. Fetch data from index.
4. Read index rebuild version again, if it is not equal to version which was read at first time, go to step 2. It is VERY important do not reorder steps 1 and 2. Such recording may lead to situation when index is rebuilding but we miss this state.

This approach works well ONLY if you do not use methods which return OIndexCursor instance. In case of you work with cursors index rebuild may cause data inconsistency issues in both:

1. Code which calls index methods to create cursor (can be avoided using steps are listed above)
2. During iteration over the cursor itself

To detect last data inconsistency issue please use cursor wrapper OIndexChangesWrapper which throws OIndexIsRebuildingException in case of index rebuild.

Both of these approaches are used in implementation of support of "live index rebuild" for SELECT SQL queries.

1. In case of index which we are going to use to speed up SELECT query is rebuilding we skip this index.
2. If index is rebuilding at the moment when we iterate over the cursor we catch OIndexIsRebuildingException exception and retry whole query again.

Returns:

amount of times when index was rebuilt since the start of the storage.

See Also:

OAbstractPaginatedStorage.command(com.orientechnologies.orient.core.command.OCommandRequestText), OIndexChangesWrapper, OIndexIsRebuildingException, ORetryQueryException

isRebuilding

boolean isRebuilding()

Returns:

Indicates whether index is rebuilding at the moment.

See Also:

getRebuildVersion()

getFirstKey

Object getFirstKey()

getLastKey

Object getLastKey()

getIndexId

int getIndexId()

isUnique

boolean isUnique()