Class KNearestNeighborClassifier

    • Field Detail

      • textFieldNames

        protected final java.lang.String[] textFieldNames
        the name of the fields used as the input text
      • classFieldName

        protected final java.lang.String classFieldName
        the name of the field used as the output text
      • k

        protected final int k
        the no. of docs to compare in order to find the nearest neighbor to the input text
      • query

        protected final Query query
        a Query used to filter the documents that should be used from this classifier's underlying LeafReader
    • Constructor Detail

      • KNearestNeighborClassifier

        public KNearestNeighborClassifier​(IndexReader indexReader,
                                          Similarity similarity,
                                          Analyzer analyzer,
                                          Query query,
                                          int k,
                                          int minDocsFreq,
                                          int minTermFreq,
                                          java.lang.String classFieldName,
                                          java.lang.String... textFieldNames)
        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
        minDocsFreq - MoreLikeThis.minDocFreq parameter
        minTermFreq - MoreLikeThis.minTermFreq parameter
        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

        protected 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