org.apache.lucene.classification

Class KNearestFuzzyClassifier

java.lang.Object

org.apache.lucene.classification.KNearestFuzzyClassifier

All Implemented Interfaces:

Classifier<BytesRef>

public class KNearestFuzzyClassifier
extends java.lang.Object
implements Classifier<BytesRef>

A k-Nearest Neighbor classifier based on NearestFuzzyQuery.

Field Summary

Fields

Modifier and Type	Field and Description
private Analyzer	analyzer
private java.lang.String	classFieldName the name of the field used as the output text
private IndexSearcher	indexSearcher an IndexSearcher used to perform queries
private int	k the no.
private Query	query a Query used to filter the documents that should be used from this classifier's underlying LeafReader
private java.lang.String[]	textFieldNames the name of the fields used as the input text

Constructor Summary

Constructors

Constructor and Description
KNearestFuzzyClassifier(IndexReader indexReader, Similarity similarity, Analyzer analyzer, Query query, int k, java.lang.String classFieldName, java.lang.String... textFieldNames) Creates a KNearestFuzzyClassifier.

Method Summary

Modifier and Type	Method and Description
ClassificationResult<BytesRef>	assignClass(java.lang.String text) Assign a class (with score) to the given text String
private java.util.List<ClassificationResult<BytesRef>>	buildListFromTopDocs(TopDocs topDocs) build a list of classification results from search results
java.util.List<ClassificationResult<BytesRef>>	getClasses(java.lang.String text) Get all the classes (sorted by score, descending) assigned to the given text String.
java.util.List<ClassificationResult<BytesRef>>	getClasses(java.lang.String text, int max) Get the first max classes (sorted by score, descending) assigned to the given text String.
private TopDocs	knnSearch(java.lang.String text)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

textFieldNames

private final java.lang.String[] textFieldNames

the name of the fields used as the input text

classFieldName

private final java.lang.String classFieldName

the name of the field used as the output text

indexSearcher

private final IndexSearcher indexSearcher

an IndexSearcher used to perform queries

k

private final int k

the no. of docs to compare in order to find the nearest neighbor to the input text

query

private final Query query

a Query used to filter the documents that should be used from this classifier's underlying LeafReader

analyzer

private final Analyzer analyzer

Constructor Detail

KNearestFuzzyClassifier

public KNearestFuzzyClassifier(IndexReader indexReader,
                               Similarity similarity,
                               Analyzer analyzer,
                               Query query,
                               int k,
                               java.lang.String classFieldName,
                               java.lang.String... textFieldNames)

Creates a KNearestFuzzyClassifier.

Parameters:

indexReader - the reader on the index to be used for classification

analyzer - an Analyzer used to analyze unseen text

similarity - the Similarity to be used by the underlying IndexSearcher or null (defaults to BM25Similarity)

query - a Query to eventually filter the docs used for training the classifier, or null if all the indexed docs should be used

k - the no. of docs to select in the MLT results to find the nearest neighbor

classFieldName - the name of the field used as the output for the classifier

textFieldNames - the name of the fields used as the inputs for the classifier, they can contain boosting indication e.g. title^10

Method Detail

assignClass

public ClassificationResult<BytesRef> assignClass(java.lang.String text)
                                           throws java.io.IOException

Description copied from interface: Classifier

Assign a class (with score) to the given text String

Specified by:

assignClass in interface Classifier<BytesRef>

Parameters:

text - a String containing text to be classified

Returns:

a ClassificationResult holding assigned class of type T and score

Throws:

java.io.IOException - If there is a low-level I/O error.

getClasses

public java.util.List<ClassificationResult<BytesRef>> getClasses(java.lang.String text)
                                                          throws java.io.IOException

Description copied from interface: Classifier

Get all the classes (sorted by score, descending) assigned to the given text String.

Specified by:

getClasses in interface Classifier<BytesRef>

Parameters:

text - a String containing text to be classified

Returns:

the whole list of ClassificationResult, the classes and scores. Returns null if the classifier can't make lists.

Throws:

java.io.IOException - If there is a low-level I/O error.

getClasses

public java.util.List<ClassificationResult<BytesRef>> getClasses(java.lang.String text,
                                                                 int max)
                                                          throws java.io.IOException

Description copied from interface: Classifier

Get the first max classes (sorted by score, descending) assigned to the given text String.

Specified by:

getClasses in interface Classifier<BytesRef>

Parameters:

text - a String containing text to be classified

max - the number of return list elements

Returns:

the whole list of ClassificationResult, the classes and scores. Cut for "max" number of elements. Returns null if the classifier can't make lists.

Throws:

java.io.IOException - If there is a low-level I/O error.

knnSearch

private TopDocs knnSearch(java.lang.String text)
                   throws java.io.IOException

Throws:

java.io.IOException

buildListFromTopDocs

private java.util.List<ClassificationResult<BytesRef>> buildListFromTopDocs(TopDocs topDocs)
                                                                     throws java.io.IOException

build a list of classification results from search results

Parameters:

topDocs - the search results as a TopDocs object

Returns:

a List of ClassificationResult, one for each existing class

Throws:

java.io.IOException - if it's not possible to get the stored value of class field

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object