Package it.unimi.di.big.mg4j.index.cluster

Class IdentityDocumentalStrategy

java.lang.Object

it.unimi.di.big.mg4j.index.cluster.IdentityDocumentalStrategy

All Implemented Interfaces:

ClusteringStrategy, DocumentalClusteringStrategy, Serializable

public class IdentityDocumentalStrategy
extends Object
implements DocumentalClusteringStrategy, Serializable

A documental strategy that maps identically local to global pointers and viceversa.

When clustering a posteriori a set of previously built renumbered indices using a DocumentalMergedCluster, local document pointers are actually global document pointers. In this case, an instance of this class should be used as a strategy for the cluster.

Author:

Sebastiano Vigna

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
IdentityDocumentalStrategy(int numberOfLocalIndices, long numberOfDocuments)	Creates a new identity documental clustering strategy.

Method Summary

Modifier and Type	Method	Description
long	globalPointer(int localIndex, long localPointer)	Returns the global document pointer given a local index and a local document pointer.
long	localPointer(long globalPointer)	Returns the local document pointer corresponding to a global document pointer.
long	numberOfDocuments(int localIndex)	Returns the number of documents that will be assigned to the given local index.
int	numberOfLocalIndices()	Returns the number of local indices handled by this strategy.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

IdentityDocumentalStrategy

public IdentityDocumentalStrategy(int numberOfLocalIndices,
                                  long numberOfDocuments)

Creates a new identity documental clustering strategy.

Parameters:

numberOfLocalIndices - the number of local indices.

numberOfDocuments - the number of documents.

Method Detail

numberOfLocalIndices

public int numberOfLocalIndices()

Description copied from interface: ClusteringStrategy

Returns the number of local indices handled by this strategy.

Specified by:

numberOfLocalIndices in interface ClusteringStrategy

Returns:

the number of local indices handled by this strategy.

localPointer

public long localPointer(long globalPointer)

Description copied from interface: DocumentalClusteringStrategy

Returns the local document pointer corresponding to a global document pointer.

Specified by:

localPointer in interface DocumentalClusteringStrategy

Parameters:

globalPointer - a global document pointer.

Returns:

the corresponding local document pointer.

globalPointer

public long globalPointer(int localIndex,
                          long localPointer)

Description copied from interface: DocumentalClusteringStrategy

Returns the global document pointer given a local index and a local document pointer.

Specified by:

globalPointer in interface DocumentalClusteringStrategy

Parameters:

localIndex - the local index.

localPointer - the local document pointer in localIndex.

Returns:

the global document pointer.

numberOfDocuments

public long numberOfDocuments(int localIndex)

Description copied from interface: DocumentalClusteringStrategy

Returns the number of documents that will be assigned to the given local index.

Specified by:

numberOfDocuments in interface DocumentalClusteringStrategy

Parameters:

localIndex - the local index.

Returns:

the number of documents that will be assigned to localIndex.

toString

public String toString()

Overrides:

toString in class Object