Package org.apache.lucene.classification.document

Class KNearestNeighborDocumentClassifier

java.lang.Object
org.apache.lucene.classification.KNearestNeighborClassifier
org.apache.lucene.classification.document.KNearestNeighborDocumentClassifier
All Implemented Interfaces:
Classifier<org.apache.lucene.util.BytesRef>, DocumentClassifier<org.apache.lucene.util.BytesRef>
public class KNearestNeighborDocumentClassifier extends KNearestNeighborClassifier implements DocumentClassifier<org.apache.lucene.util.BytesRef>
A k-Nearest Neighbor Document classifier (see http://en.wikipedia.org/wiki/K-nearest_neighbors) based on MoreLikeThis .
WARNING: This API is experimental and might change in incompatible ways in the next release.

  • Field Details

    • field2analyzer

      protected final Map<String,org.apache.lucene.analysis.Analyzer> field2analyzer
      map of per field analyzers

  • Constructor Details

    • KNearestNeighborDocumentClassifier

      public KNearestNeighborDocumentClassifier(org.apache.lucene.index.IndexReader indexReader, org.apache.lucene.search.similarities.Similarity similarity, org.apache.lucene.search.Query query, int k, int minDocsFreq, int minTermFreq, String classFieldName, Map<String,org.apache.lucene.analysis.Analyzer> field2analyzer, String... textFieldNames) throws IOException
      Creates a KNearestNeighborClassifier.
      Parameters:
      indexReader - the reader on the index to be used for classification
      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
      minDocsFreq - MoreLikeThis.minDocFreq parameter
      minTermFreq - MoreLikeThis.minTermFreq parameter
      classFieldName - the name of the field used as the output for the classifier
      field2analyzer - map with key a field name and the related {org.apache.lucene.analysis.Analyzer}
      textFieldNames - the name of the fields used as the inputs for the classifier, they can contain boosting indication e.g. title^10
      Throws:
      IOException

  • Method Details

    • assignClass

      public ClassificationResult<org.apache.lucene.util.BytesRef> assignClass(org.apache.lucene.document.Document document) throws IOException
      Description copied from interface: DocumentClassifier
      Assign a class (with score) to the given Document
      Specified by:
      assignClass in interface DocumentClassifier<org.apache.lucene.util.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<org.apache.lucene.util.BytesRef>> getClasses(org.apache.lucene.document.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<org.apache.lucene.util.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<org.apache.lucene.util.BytesRef>> getClasses(org.apache.lucene.document.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<org.apache.lucene.util.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.