Class FixedShingleFilter

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    public final class FixedShingleFilter
    extends TokenFilter
    A FixedShingleFilter constructs shingles (token n-grams) from a token stream. In other words, it creates combinations of tokens as a single token.

    Unlike the ShingleFilter, FixedShingleFilter only emits shingles of a fixed size, and never emits unigrams, even at the end of a TokenStream. In addition, if the filter encounters stacked tokens (eg synonyms), then it will output stacked shingles

    For example, the sentence "please divide this sentence into shingles" might be tokenized into shingles "please divide", "divide this", "this sentence", "sentence into", and "into shingles".

    This filter handles position increments > 1 by inserting filler tokens (tokens with termtext "_").

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

      • FixedShingleFilter

        public FixedShingleFilter​(TokenStream input,
                                  int shingleSize)
        Creates a FixedShingleFilter over an input token stream
        Parameters:
        input - the input stream
        shingleSize - the shingle size
      • FixedShingleFilter

        public FixedShingleFilter​(TokenStream input,
                                  int shingleSize,
                                  String tokenSeparator,
                                  String fillerToken)
        Creates a FixedShingleFilter over an input token stream
        Parameters:
        input - the input tokenstream
        shingleSize - the shingle size
        tokenSeparator - a String to use as a token separator
        fillerToken - a String to use to represent gaps in the input stream (due to eg stopwords)