de.lmu.ifi.dbs.elki.database.ids
Class DBIDUtil

java.lang.Object
  de.lmu.ifi.dbs.elki.database.ids.DBIDUtil

public final class DBIDUtil
extends Object

DBID Utility functions.

Field Summary

static EmptyDBIDs

EMPTYDBIDS Final, global copy of empty DBIDs.

Constructor Summary

private

DBIDUtil() Static - no public constructor.

Method Summary

static void	deallocateDBIDRange(DBIDRange range) Deallocate a static DBID range.
static void	deallocateSingleDBID(DBID id) Return a single DBID for reuse.
static ModifiableDBIDs	difference(DBIDs ids1, DBIDs ids2) Returns the difference of the two specified collection of IDs.
static ArrayDBIDs	ensureArray(DBIDs ids) Ensure that the given DBIDs are array-indexable.
static ModifiableDBIDs	ensureModifiable(DBIDs ids) Ensure modifiable
static SetDBIDs	ensureSet(DBIDs ids) Ensure that the given DBIDs support fast "contains" operations.
static DBID	generateSingleDBID() Generate a single DBID
static DBIDRange	generateStaticDBIDRange(int size) Generate a static DBID range.
ByteBufferSerializer<DBID>	getDBIDSerializer() Get a serializer for DBIDs
ByteBufferSerializer<DBID>	getDBIDSerializerStatic() Get a serializer for DBIDs with static size
static DBID	importInteger(int id) Import an Integer DBID.
static ModifiableDBIDs	intersection(DBIDs first, DBIDs second) Compute the set intersection of two sets.
static StaticDBIDs	makeUnmodifiable(DBIDs existing) Wrap an existing DBIDs collection to be unmodifiable.
static ArrayModifiableDBIDs	newArray() Make a new (modifiable) array of DBIDs.
static ArrayModifiableDBIDs	newArray(DBIDs existing) Make a new (modifiable) array of DBIDs.
static ArrayModifiableDBIDs	newArray(int size) Make a new (modifiable) array of DBIDs.
static HashSetModifiableDBIDs	newHashSet() Make a new (modifiable) hash set of DBIDs.
static HashSetModifiableDBIDs	newHashSet(DBIDs existing) Make a new (modifiable) hash set of DBIDs.
static HashSetModifiableDBIDs	newHashSet(int size) Make a new (modifiable) hash set of DBIDs.
static DBIDPair	newPair(DBID id1, DBID id2) Make a DBID pair.
static TreeSetModifiableDBIDs	newTreeSet() Make a new (modifiable) tree set of DBIDs.
static TreeSetModifiableDBIDs	newTreeSet(DBIDs existing) Make a new (modifiable) tree set of DBIDs.
static TreeSetModifiableDBIDs	newTreeSet(int size) Make a new (modifiable) tree set of DBIDs.
static ModifiableDBIDs	randomSample(DBIDs source, int k, long seed) Produce a random sample of the given DBIDs
static ModifiableDBIDs	union(DBIDs ids1, DBIDs ids2) Returns the union of the two specified collection of IDs.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTYDBIDS

public static final EmptyDBIDs EMPTYDBIDS

Final, global copy of empty DBIDs.

Constructor Detail

DBIDUtil

private DBIDUtil()

Static - no public constructor.

Method Detail

importInteger

public static DBID importInteger(int id)

Import an Integer DBID.

Parameters:

id - Integer ID

Returns:

DBID

getDBIDSerializer

public ByteBufferSerializer<DBID> getDBIDSerializer()

Get a serializer for DBIDs

Returns:

DBID serializer

getDBIDSerializerStatic

public ByteBufferSerializer<DBID> getDBIDSerializerStatic()

Get a serializer for DBIDs with static size

Returns:

DBID serializer

generateSingleDBID

public static DBID generateSingleDBID()

Generate a single DBID

Returns:

A single DBID

deallocateSingleDBID

public static void deallocateSingleDBID(DBID id)

Return a single DBID for reuse.

Parameters:

id - DBID to deallocate

generateStaticDBIDRange

public static DBIDRange generateStaticDBIDRange(int size)

Generate a static DBID range.

Parameters:

size - Requested size

Returns:

DBID range

deallocateDBIDRange

public static void deallocateDBIDRange(DBIDRange range)

Deallocate a static DBID range.

Parameters:

range - Range to deallocate

newArray

public static ArrayModifiableDBIDs newArray()

Make a new (modifiable) array of DBIDs.

Returns:

New array

newHashSet

public static HashSetModifiableDBIDs newHashSet()

Make a new (modifiable) hash set of DBIDs.

Returns:

New hash set

newTreeSet

public static TreeSetModifiableDBIDs newTreeSet()

Make a new (modifiable) tree set of DBIDs.

Returns:

New tree set

newArray

public static ArrayModifiableDBIDs newArray(int size)

Make a new (modifiable) array of DBIDs.

Parameters:

size - Size hint

Returns:

New array

newHashSet

public static HashSetModifiableDBIDs newHashSet(int size)

Make a new (modifiable) hash set of DBIDs.

Parameters:

size - Size hint

Returns:

New hash set

newTreeSet

public static TreeSetModifiableDBIDs newTreeSet(int size)

Make a new (modifiable) tree set of DBIDs.

Parameters:

size - Size hint

Returns:

New tree set

newArray

public static ArrayModifiableDBIDs newArray(DBIDs existing)

Make a new (modifiable) array of DBIDs.

Parameters:

existing - Existing DBIDs

Returns:

New array

newHashSet

public static HashSetModifiableDBIDs newHashSet(DBIDs existing)

Make a new (modifiable) hash set of DBIDs.

Parameters:

existing - Existing DBIDs

Returns:

New hash set

newTreeSet

public static TreeSetModifiableDBIDs newTreeSet(DBIDs existing)

Make a new (modifiable) tree set of DBIDs.

Parameters:

existing - Existing DBIDs

Returns:

New tree set

intersection

public static ModifiableDBIDs intersection(DBIDs first,
                                           DBIDs second)

Compute the set intersection of two sets.

Parameters:

first - First set

second - Second set

Returns:

result.

union

public static ModifiableDBIDs union(DBIDs ids1,
                                    DBIDs ids2)

Returns the union of the two specified collection of IDs.

Parameters:

ids1 - the first collection

ids2 - the second collection

Returns:

the union of ids1 and ids2 without duplicates

difference

public static ModifiableDBIDs difference(DBIDs ids1,
                                         DBIDs ids2)

Returns the difference of the two specified collection of IDs.

Parameters:

ids1 - the first collection

ids2 - the second collection

Returns:

the difference of ids1 minus ids2

makeUnmodifiable

public static StaticDBIDs makeUnmodifiable(DBIDs existing)

Wrap an existing DBIDs collection to be unmodifiable.

Parameters:

existing - Existing collection

Returns:

Unmodifiable collection

ensureArray

public static ArrayDBIDs ensureArray(DBIDs ids)

Ensure that the given DBIDs are array-indexable.

Parameters:

ids -

Returns:

Array DBIDs.

ensureSet

public static SetDBIDs ensureSet(DBIDs ids)

Ensure that the given DBIDs support fast "contains" operations.

Parameters:

ids -

Returns:

Array DBIDs.

ensureModifiable

public static ModifiableDBIDs ensureModifiable(DBIDs ids)

Ensure modifiable

Parameters:

ids -

Returns:

Array DBIDs.

newPair

public static DBIDPair newPair(DBID id1,
                               DBID id2)

Make a DBID pair.

Parameters:

id1 - first ID

id2 - second ID

Returns:

DBID pair

randomSample

public static ModifiableDBIDs randomSample(DBIDs source,
                                           int k,
                                           long seed)

Produce a random sample of the given DBIDs

Parameters:

source - Original DBIDs

k - k Parameter

seed - Random generator seed

Returns:

new DBIDs