Package elki.database.relation

Class ProjectedView<IN,OUT>

java.lang.Object

elki.database.relation.ProjectedView<IN,OUT>

Type Parameters:

IN - Vector type

OUT - Vector type

All Implemented Interfaces:

Relation<OUT>

public class ProjectedView<IN,OUT>
extends java.lang.Object
implements Relation<OUT>

Projected relation view (non-materialized)

Since:

0.5.0

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field	Description
private Relation<? extends IN>	inner	The wrapped representation where we get the IDs from.
private Projection<IN,OUT>	projection	The projection we use.

Constructor Summary

Constructors

Constructor	Description
ProjectedView(Relation<? extends IN> inner, Projection<IN,OUT> projection)	Constructor.

Method Summary

Modifier and Type	Method	Description
OUT	get(DBIDRef id)	Get the representation of an object.
SimpleTypeInformation<OUT>	getDataTypeInformation()	Get the data type of this representation
DBIDs	getDBIDs()	Get the IDs the query is defined for.
java.lang.String	getLongName()	Get a long (human readable) name for the relation.
DBIDIter	iterDBIDs()	Get an iterator access to the DBIDs.
int	size()	Get the number of DBIDs.

Methods inherited from class java.lang.Object

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

Methods inherited from interface elki.database.relation.Relation

forEach

Field Detail

inner

private final Relation<? extends IN> inner

The wrapped representation where we get the IDs from.

projection

private Projection<IN,OUT> projection

The projection we use.

Constructor Detail

ProjectedView

public ProjectedView(Relation<? extends IN> inner,
                     Projection<IN,OUT> projection)

Constructor.

Parameters:

inner - Inner relation

projection - Projection function

Method Detail

getLongName

public java.lang.String getLongName()

Description copied from interface: Relation

Get a long (human readable) name for the relation.

Specified by:

getLongName in interface Relation<IN>

Returns:

Relation name

get

public OUT get(DBIDRef id)

Description copied from interface: Relation

Get the representation of an object.

Specified by:

get in interface Relation<IN>

Parameters:

id - Object ID

Returns:

object instance

getDataTypeInformation

public SimpleTypeInformation<OUT> getDataTypeInformation()

Description copied from interface: Relation

Get the data type of this representation

Specified by:

getDataTypeInformation in interface Relation<IN>

Returns:

Data type

getDBIDs

public DBIDs getDBIDs()

Description copied from interface: Relation

Get the IDs the query is defined for.

If possible, prefer Relation.iterDBIDs().

Specified by:

getDBIDs in interface Relation<IN>

Returns:

IDs this is defined for

iterDBIDs

public DBIDIter iterDBIDs()

Description copied from interface: Relation

Get an iterator access to the DBIDs.

To iterate over all IDs, use the following code fragment:

 
 for(DBIDIter iter = relation.iterDBIDs(); iter.valid(); iter.advance()) {
    relation.get(iter); // Get the current element
 }
 
 

Specified by:

iterDBIDs in interface Relation<IN>

Returns:

iterator for the DBIDs.

size

public int size()

Description copied from interface: Relation

Get the number of DBIDs.

Specified by:

size in interface Relation<IN>

Returns:

Size