de.lmu.ifi.dbs.elki.data
Class KNNList<D extends Distance<D>>

java.lang.Object
  de.lmu.ifi.dbs.elki.data.KNNList<D>

Type Parameters:

D - Distance class

public class KNNList<D extends Distance<D>>
extends Object

A wrapper class for storing the k most similar comparable objects.

Author:

Elke Achtert

Field Summary

private D	infiniteDistance The infinite distance.
private int	k The maximum size of this list.
private SortedSet<DistanceResultPair<D>>	list The underlying set.

Constructor Summary

KNNList(int k, D infiniteDistance)
Creates a new KNNList with the specified parameters.

Method Summary

boolean	add(DistanceResultPair<D> o) Adds a new object to this list.
List<D>	distancesToList() Return a list containing just the distances
boolean	equals(Object o) Indicates whether some other object is "equal to" this one.
int	getK() Returns the maximum size of this list.
D	getKNNDistance() Returns the k-th distance of this list (e.g. the key of the k-th element).
D	getMaximumDistance() Returns the maximum distance of this list (e.g. the key of the last element).
int	hashCode() Combine list hash code with the value of k.
List<Integer>	idsToList() Return a list containing only the object IDs
int	size() Returns the current size of this list.
List<DistanceResultPair<D>>	toList() Returns a list representation of this KList.
String	toString() Returns a string representation of the object.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

list

private SortedSet<DistanceResultPair<D extends Distance<D>>> list

The underlying set.

k

private int k

The maximum size of this list.

infiniteDistance

private D extends Distance<D> infiniteDistance

The infinite distance.

Constructor Detail

KNNList

public KNNList(int k,
               D infiniteDistance)

Creates a new KNNList with the specified parameters.

Parameters:

k - the number k of objects to be stored

infiniteDistance - the infinite distance

Method Detail

add

public boolean add(DistanceResultPair<D> o)

Adds a new object to this list. If this list contains already k entries and the key of the specified object o is less than the key of the last entry, the last entry will be deleted.

Parameters:

o - the object to be added

Returns:

true, if o has been added, false otherwise.

getKNNDistance

public D getKNNDistance()

Returns the k-th distance of this list (e.g. the key of the k-th element). If this list is empty or contains less than k elements, an infinite key will be returned.

Returns:

the maximum distance of this list

getMaximumDistance

public D getMaximumDistance()

Returns the maximum distance of this list (e.g. the key of the last element). If this list is empty an infinite key will be returned.

Returns:

the maximum distance of this list

toList

public List<DistanceResultPair<D>> toList()

Returns a list representation of this KList.

Returns:

a list representation of this KList

distancesToList

public List<D> distancesToList()

Return a list containing just the distances

Returns:

list of distances

idsToList

public List<Integer> idsToList()

Return a list containing only the object IDs

Returns:

list of object ids

size

public int size()

Returns the current size of this list.

Returns:

the current size of this list

getK

public int getK()

Returns the maximum size of this list.

Returns:

the maximum size of this list

toString

public String toString()

Returns a string representation of the object.

Overrides:

toString in class Object

Returns:

a string representation of the object.

equals

public boolean equals(Object o)

Indicates whether some other object is "equal to" this one.

Overrides:

equals in class Object

Parameters:

o - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

hashCode

public int hashCode()

Combine list hash code with the value of k.

Overrides:

hashCode in class Object

See Also:

Object.hashCode()