Package org.apache.lucene.classification
Class BM25NBClassifier
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- org.apache.lucene.classification.BM25NBClassifier
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- All Implemented Interfaces:
Classifier<BytesRef>
public class BM25NBClassifier extends Object implements Classifier<BytesRef>
A classifier approximating naive bayes classifier by using pure queries on BM25.- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Constructor Summary
Constructors Constructor Description BM25NBClassifier(IndexReader indexReader, Analyzer analyzer, Query query, String classFieldName, String... textFieldNames)Creates a new NaiveBayes classifier.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description ClassificationResult<BytesRef>assignClass(String inputDocument)Assign a class (with score) to the given text StringList<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 firstmaxclasses (sorted by score, descending) assigned to the given text String.
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Constructor Detail
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BM25NBClassifier
public BM25NBClassifier(IndexReader indexReader, Analyzer analyzer, Query query, String classFieldName, String... textFieldNames)
Creates a new NaiveBayes classifier.- Parameters:
indexReader- the reader on the index to be used for classificationanalyzer- anAnalyzerused to analyze unseen textquery- aQueryto eventually filter the docs used for training the classifier, ornullif all the indexed docs should be usedclassFieldName- 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 fieldtextFieldNames- the name of the fields used as the inputs for the classifier, NO boosting supported per field
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Method Detail
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assignClass
public ClassificationResult<BytesRef> assignClass(String inputDocument) throws IOException
Description copied from interface:ClassifierAssign a class (with score) to the given text String- Specified by:
assignClassin interfaceClassifier<BytesRef>- Parameters:
inputDocument- a String containing text to be classified- Returns:
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ClassificationResultholding assigned class of typeTand score - Throws:
IOException- If there is a low-level I/O error.
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getClasses
public List<ClassificationResult<BytesRef>> getClasses(String text) throws IOException
Description copied from interface:ClassifierGet all the classes (sorted by score, descending) assigned to the given text String.- Specified by:
getClassesin interfaceClassifier<BytesRef>- Parameters:
text- a String containing text to be classified- Returns:
- the whole list of
ClassificationResult, the classes and scores. Returnsnullif the classifier can't make lists. - Throws:
IOException- If there is a low-level I/O error.
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getClasses
public List<ClassificationResult<BytesRef>> getClasses(String text, int max) throws IOException
Description copied from interface:ClassifierGet the firstmaxclasses (sorted by score, descending) assigned to the given text String.- Specified by:
getClassesin interfaceClassifier<BytesRef>- Parameters:
text- a String containing text to be classifiedmax- the number of return list elements- Returns:
- the whole list of
ClassificationResult, the classes and scores. Cut for "max" number of elements. Returnsnullif the classifier can't make lists. - Throws:
IOException- If there is a low-level I/O error.
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