Package org.aksw.limes.core.io.mapping

Class MemoryMapping

java.lang.Object

org.aksw.limes.core.io.mapping.AMapping

org.aksw.limes.core.io.mapping.MemoryMapping

All Implemented Interfaces:

Serializable, IMapping

public class MemoryMapping
extends AMapping

This class contains the mappings computed by an organizer. Each URI from the second knowledge base is mapped to the URI of instances from the first knowledge base and the corresponding similarity value. This is a help class for further processing that simply stores the mapping results in memory. It is important to notice that if (s, t, sim1) are already in the mapping and (s, t, sim2) is added then the mapping will contain (s, t, max(sim1, sim2))

Version:

Nov 24, 2015

Author:

Axel-C. Ngonga Ngomo (ngonga@informatik.uni-leipzig.de), Mohamed Sherif <sherif @ informatik.uni-leipzig.de>

See Also:

Serialized Form

Field Summary

Fields inherited from class org.aksw.limes.core.io.mapping.AMapping

map, predicate, reversedMap, size

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MemoryMapping()

Method Summary

Modifier and Type	Method	Description
void	add(String source, String target, double similarity)	Add one entry to the mapping
void	add(String uri, HashMap<String,Double> instances)	Add a batch of similarities to the mapping
boolean	contains(String sourceInstance, String targetInstance)	Checks whether a mapping contains a particular entry
static AMapping	generateRandomMapping(int mappingSize, int minSize, int maxSize)
AMapping	getBestOneToNMapping()	Computes the best one to n mapping for the current mapping, i.e., for each element of the source, it gets the best t from target.
double	getConfidence(String sourceInstance, String targetInstance)	Checks whether the map contains a certain pair.
int	getNumberofMappings()	Computes the total number of mappings contained in the object
int	getNumberofPositiveMappings()	Computes the number of mappings with value greater than 0 contained in the object
AMapping	getOnlyPositiveExamples()
AMapping	getSubMap(double threshold)	Returns a mapping that contains all elements of the current mapping that have similarity above the threshold.
void	initReversedMap()	Fills the whole content of the current map into the reversed map, which uses the similarity scores as key.
String	pairsOutput()
AMapping	reverseSourceTarget()	Reverses source and target
AMapping	scale(double d)
int	size()
String	toString()
AMapping	trim()
AMapping	union(AMapping other)	Union of two maps: returns all pairs of sources s and targets t of this map and the other.

Methods inherited from class org.aksw.limes.core.io.mapping.AMapping

equals, getBestOneToOneMappings, getMap, getPredicate, getPredicateURI, getReversedMap, getSize, hashCode, setMap, setPredicate, setSize

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryMapping

protected MemoryMapping()

Method Detail

generateRandomMapping

public static AMapping generateRandomMapping(int mappingSize,
                                             int minSize,
                                             int maxSize)

initReversedMap

public void initReversedMap()

Fills the whole content of the current map into the reversed map, which uses the similarity scores as key.

getSubMap

public AMapping getSubMap(double threshold)

Returns a mapping that contains all elements of the current mapping that have similarity above the threshold. Basically the same as filter(mapping, threshold) but should be faster

Specified by:

getSubMap in class AMapping

Parameters:

threshold - Similarity threshold for filtering

Returns:

Mapping that contains all elements (s,t) with sim(s,t) < = threshold

add

public void add(String uri,
                HashMap<String,Double> instances)

Add a batch of similarities to the mapping

Specified by:

add in class AMapping

Parameters:

uri - A resource from the source knowledge base

instances - Map containing uris from the target knowledge base and their similarity to uri

size

public int size()

Specified by:

size in class AMapping

add

public void add(String source,
                String target,
                double similarity)

Add one entry to the mapping

Specified by:

add in class AMapping

Parameters:

source - Uri in the source knowledge bases

target - Mapping uri in the target knowledge base

similarity - Similarity of uri and mappingUri

getConfidence

public double getConfidence(String sourceInstance,
                            String targetInstance)

Checks whether the map contains a certain pair. If yes, its similarity is returned. Else 0 is returned

Specified by:

getConfidence in class AMapping

Parameters:

sourceInstance - Instance from the source knowledge base

targetInstance - Instance from the target knowledge base

Returns:

Similarity of the two instances according to the mapping

contains

public boolean contains(String sourceInstance,
                        String targetInstance)

Checks whether a mapping contains a particular entry

Specified by:

contains in class AMapping

Parameters:

sourceInstance - Key URI

targetInstance - Value URI

Returns:

True if mapping contains (key, value), else false.

toString

public String toString()

Overrides:

toString in class Object

getNumberofMappings

public int getNumberofMappings()

Computes the total number of mappings contained in the object

Specified by:

getNumberofMappings in class AMapping

Returns:

Total number of mappings

getNumberofPositiveMappings

public int getNumberofPositiveMappings()

Computes the number of mappings with value greater than 0 contained in the object

Specified by:

getNumberofPositiveMappings in class AMapping

Returns:

number of mappings with value greater than 0

getBestOneToNMapping

public AMapping getBestOneToNMapping()

Computes the best one to n mapping for the current mapping, i.e., for each element of the source, it gets the best t from target. This does not mean an 1 to 1 mapping, as a t can be mapped to several s.

Specified by:

getBestOneToNMapping in class AMapping

Returns:

Best one to one mapping

reverseSourceTarget

public AMapping reverseSourceTarget()

Reverses source and target

Specified by:

reverseSourceTarget in class AMapping

Returns:

Reversed map

scale

public AMapping scale(double d)

trim

public AMapping trim()

pairsOutput

public String pairsOutput()

union

public AMapping union(AMapping other)

Union of two maps: returns all pairs of sources s and targets t of this map and the other. The scores will be the maximum score of either this or the other.

Parameters:

other - , the second mapping

Returns:

the union of the two mappings

getOnlyPositiveExamples

public AMapping getOnlyPositiveExamples()

Specified by:

getOnlyPositiveExamples in class AMapping