Package org.apache.lucene.classification.document

# Class SimpleNaiveBayesDocumentClassifier

java.lang.Object
org.apache.lucene.classification.SimpleNaiveBayesClassifier
org.apache.lucene.classification.document.SimpleNaiveBayesDocumentClassifier

All Implemented Interfaces:
  `Classifier<BytesRef>`, `DocumentClassifier<BytesRef>`

public class SimpleNaiveBayesDocumentClassifier extends SimpleNaiveBayesClassifier implements DocumentClassifier<BytesRef>
A simplistic Lucene based NaiveBayes classifier, see `http://en.wikipedia.org/wiki/Naive_Bayes_classifier`

WARNING: This API is experimental and might change in incompatible ways in the next release.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected final Map<String,Analyzer>`
  `field2analyzer`
  `Analyzer` to be used for tokenizing document fields

  ### Fields inherited from class org.apache.lucene.classification.SimpleNaiveBayesClassifier

  `analyzer, classFieldName, indexReader, indexSearcher, query, textFieldNames`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `SimpleNaiveBayesDocumentClassifier(IndexReader indexReader, Query query, String classFieldName, Map<String,Analyzer> field2analyzer, String... textFieldNames)`
  Creates a new NaiveBayes classifier.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `ClassificationResult<BytesRef>`
  `assignClass(Document document)`
  Assign a class (with score) to the given `Document`
  `List<ClassificationResult<BytesRef>>`
  `getClasses(Document document)`
  Get all the classes (sorted by score, descending) assigned to the given `Document`.
  `List<ClassificationResult<BytesRef>>`
  `getClasses(Document document, int max)`
  Get the first `max` classes (sorted by score, descending) assigned to the given text String.
  `protected String[]`
  `getTokenArray(TokenStream tokenizedText)`
  Returns a token array from the `TokenStream` in input

  ### Methods inherited from class org.apache.lucene.classification.SimpleNaiveBayesClassifier

  `assignClass, assignClassNormalizedList, countDocsWithClass, getClasses, getClasses, normClassificationResults, tokenize`

  ### Methods inherited from class java.lang.Object

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

- ## Field Details

  - ### field2analyzer

    protected final Map<String,Analyzer> field2analyzer
    `Analyzer` to be used for tokenizing document fields

- ## Constructor Details

  - ### SimpleNaiveBayesDocumentClassifier

    public SimpleNaiveBayesDocumentClassifier(IndexReader indexReader, Query query, String classFieldName, Map<String,Analyzer> field2analyzer, String... textFieldNames)
    Creates a new NaiveBayes classifier.
    Parameters:
      `indexReader` - the reader on the index to be used for classification
      `query` - a `Query` to eventually filter the docs used for training the classifier, or `null` if all the indexed docs should be used
      `classFieldName` - the name of the field used as the output for the classifier NOTE: must not be heavely analyzed as the returned class will be a token indexed for this field
      `textFieldNames` - the name of the fields used as the inputs for the classifier, they can contain boosting indication e.g. title^10

- ## Method Details

  - ### assignClass

    public ClassificationResult<BytesRef> assignClass(Document document) throws IOException
    Description copied from interface: `DocumentClassifier`
    Assign a class (with score) to the given `Document`
    Specified by:
      `assignClass` in interface `DocumentClassifier<BytesRef>`
    Parameters:
      `document` - a `Document` to be classified. Fields are considered features for the classification.
    Returns:
      a `ClassificationResult` holding assigned class of type `T` and score
    Throws:
      `IOException` - If there is a low-level I/O error.

  - ### getClasses

    public List<ClassificationResult<BytesRef>> getClasses(Document document) throws IOException
    Description copied from interface: `DocumentClassifier`
    Get all the classes (sorted by score, descending) assigned to the given `Document`.
    Specified by:
      `getClasses` in interface `DocumentClassifier<BytesRef>`
    Parameters:
      `document` - a `Document` to be classified. Fields are considered features for the classification.
    Returns:
      the whole list of `ClassificationResult`, the classes and scores. Returns `null` if the classifier can't make lists.
    Throws:
      `IOException` - If there is a low-level I/O error.

  - ### getClasses

    public List<ClassificationResult<BytesRef>> getClasses(Document document, int max) throws IOException
    Description copied from interface: `DocumentClassifier`
    Get the first `max` classes (sorted by score, descending) assigned to the given text String.
    Specified by:
      `getClasses` in interface `DocumentClassifier<BytesRef>`
    Parameters:
      `document` - a `Document` to be classified. Fields are considered features for the classification.
      `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:
      `IOException` - If there is a low-level I/O error.

  - ### getTokenArray

    protected String[] getTokenArray(TokenStream tokenizedText) throws IOException
    Returns a token array from the `TokenStream` in input
    Parameters:
      `tokenizedText` - the tokenized content of a field
    Returns:
      a `String` array of the resulting tokens
    Throws:
      `IOException` - If tokenization fails because there is a low-level I/O error