org.apache.lucene.classification

## Class KNearestFuzzyClassifier

- java.lang.Object
- - org.apache.lucene.classification.KNearestFuzzyClassifier

- All Implemented Interfaces:
    Classifier<BytesRef>

      public class KNearestFuzzyClassifier
      extends Object
      implements Classifier<BytesRef>

  A k-Nearest Neighbor classifier based on `NearestFuzzyQuery`.
  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Constructor Summary

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

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `ClassificationResult<BytesRef>` | `assignClass(String text)` Assign a class (with score) to the given text String
    `List<ClassificationResult<BytesRef>>` | `getClasses(String text)` Get all the classes (sorted by score, descending) assigned to the given text String.
    `List<ClassificationResult<BytesRef>>` | `getClasses(String text, int max)` Get the first `max` classes (sorted by score, descending) assigned to the given text String.
    `String` | `toString()`

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

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

- - ### Constructor Detail

    - #### KNearestFuzzyClassifier

          public KNearestFuzzyClassifier(IndexReader indexReader,
                                         Similarity similarity,
                                         Analyzer analyzer,
                                         Query query,
                                         int k,
                                         String classFieldName,
                                         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(String text)
                                                     throws 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:
        `IOException` - If there is a low-level I/O error.

    - #### getClasses

          public List<ClassificationResult<BytesRef>> getClasses(String text)
                                                          throws 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:
        `IOException` - If there is a low-level I/O error.

    - #### getClasses

          public List<ClassificationResult<BytesRef>> getClasses(String text,
                                                                 int max)
                                                          throws 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:
        `IOException` - If there is a low-level I/O error.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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