org.simmetrics.metrics

Class JaroWinkler

java.lang.Object

org.simmetrics.metrics.JaroWinkler

All Implemented Interfaces:

Distance<String>, Metric<String>, StringDistance, StringMetric

public final class JaroWinkler
extends Object
implements StringMetric, StringDistance

Calculates the Jaro-Winkler distance (similarity) over two strings.

similarity(a,b) = jaro-winkler(a,b)
distance(a,b) = 1 - similarity(a,b)

Can be configured with a prefix adjustment scale, max prefix length and boost threshold.

This class is immutable and thread-safe.

See Also:

Wikipedia - Jaro-Winkler distance, Jaro

Constructor Summary

Constructors

Constructor and Description
JaroWinkler() Constructs a new JaroWinkler metric.
JaroWinkler(float boostThreshold, float prefixScale, int maxPrefixLength) Constructs a new JaroWinkler metric.

Method Summary

Modifier and Type	Method and Description
float	compare(String a, String b) Measures the similarity between strings a and b.
static JaroWinkler	createWithBoostThreshold() Constructs a new JaroWinkler metric with Winklers boost threshold of 0.7.
float	distance(String a, String b) Measures the distance between string a and b.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

JaroWinkler

public JaroWinkler()

Constructs a new JaroWinkler metric.

JaroWinkler

public JaroWinkler(float boostThreshold,
                   float prefixScale,
                   int maxPrefixLength)

Constructs a new JaroWinkler metric.

Parameters:

boostThreshold - minimum jaro score for which the score is boosted

prefixScale - scale at which a common prefix adds a bonus

maxPrefixLength - cutoff at which a longer common prefix does not improve the score

Method Detail

createWithBoostThreshold

public static JaroWinkler createWithBoostThreshold()

Constructs a new JaroWinkler metric with Winklers boost threshold of 0.7.

Returns:

a new JaroWinkler metric

distance

public float distance(String a,
                      String b)

Description copied from interface: StringDistance

Measures the distance between string a and b. The measurement results in a non-negative value. A value of 0.0 indicates that a and b are similar.

Specified by:

distance in interface Distance<String>

Specified by:

distance in interface StringDistance

Parameters:

a - string a to compare

b - string b to compare

Returns:

a non-negative value

compare

public float compare(String a,
                     String b)

Description copied from interface: StringMetric

Measures the similarity between strings a and b. The measurement results in a value between 0 and 1 (inclusive). A value of zero indicates that the strings are dissimilar, a value of 1 indicates they are similar.

Specified by:

compare in interface Metric<String>

Specified by:

compare in interface StringMetric

Parameters:

a - string a to compare

b - string b to compare

Returns:

a value between 0 and 1 inclusive indicating similarity

toString

public String toString()

Overrides:

toString in class Object