Package org.apache.lucene.search.highlight

Class TokenSources

java.lang.Object
org.apache.lucene.search.highlight.TokenSources
public class TokenSources extends Object
Convenience methods for obtaining a TokenStream for use with the Highlighter - can obtain from term vectors with offsets and positions or from an Analyzer re-parsing the stored content.
See Also:

  • Method Details

    • getTokenStream

      public static TokenStream getTokenStream(String field, Fields tvFields, String text, Analyzer analyzer, int maxStartOffset) throws IOException
      Get a token stream from either un-inverting a term vector if possible, or by analyzing the text.

      WARNING: Don't call this if there is more than one value for this field. If there are, and if there are term vectors, then there is a single tokenstream with offsets suggesting all the field values were concatenated.

      Parameters:
      field - The field to either get term vectors from or to analyze the text from.
      tvFields - from IndexReader.getTermVectors(int). Possibly null. For performance, this instance should be re-used for the same document (e.g. when highlighting multiple fields).
      text - the text to analyze, failing term vector un-inversion
      analyzer - the analyzer to analyze text with, failing term vector un-inversion
      maxStartOffset - Terms with a startOffset greater than this aren't returned. Use -1 for no limit. Suggest using Highlighter.getMaxDocCharsToAnalyze() - 1.
      Returns:
      a token stream from either term vectors, or from analyzing the text. Never null.
      Throws:
      IOException

    • getTermVectorTokenStreamOrNull

      public static TokenStream getTermVectorTokenStreamOrNull(String field, Fields tvFields, int maxStartOffset) throws IOException
      Get a token stream by un-inverting the term vector. This method returns null if tvFields is null or if the field has no term vector, or if the term vector doesn't have offsets. Positions are recommended on the term vector but it isn't strictly required.
      Parameters:
      field - The field to get term vectors from.
      tvFields - from IndexReader.getTermVectors(int). Possibly null. For performance, this instance should be re-used for the same document (e.g. when highlighting multiple fields).
      maxStartOffset - Terms with a startOffset greater than this aren't returned. Use -1 for no limit. Suggest using Highlighter.getMaxDocCharsToAnalyze() - 1
      Returns:
      a token stream from term vectors. Null if no term vectors with the right options.
      Throws:
      IOException

    • getAnyTokenStream

      @Deprecated public static TokenStream getAnyTokenStream(IndexReader reader, int docId, String field, Document document, Analyzer analyzer) throws IOException
      Deprecated.
      A convenience method that tries to first get a TokenStreamFromTermVector for the specified docId, then, falls back to using the passed in Document to retrieve the TokenStream. This is useful when you already have the document, but would prefer to use the vector first.
      Parameters:
      reader - The IndexReader to use to try and get the vector from
      docId - The docId to retrieve.
      field - The field to retrieve on the document
      document - The document to fall back on
      analyzer - The analyzer to use for creating the TokenStream if the vector doesn't exist
      Returns:
      The TokenStream for the IndexableField on the Document
      Throws:
      IOException - if there was an error loading

    • getAnyTokenStream

      @Deprecated public static TokenStream getAnyTokenStream(IndexReader reader, int docId, String field, Analyzer analyzer) throws IOException
      Deprecated.
      A convenience method that tries a number of approaches to getting a token stream. The cost of finding there are no termVectors in the index is minimal (1000 invocations still registers 0 ms). So this "lazy" (flexible?) approach to coding is probably acceptable
      Returns:
      null if field not stored correctly
      Throws:
      IOException - If there is a low-level I/O error

    • getTokenStream

      @Deprecated public static TokenStream getTokenStream(Terms vector, boolean tokenPositionsGuaranteedContiguous) throws IOException
      Deprecated.
      Simply calls getTokenStream(org.apache.lucene.index.Terms) now.
      Throws:
      IOException

    • getTokenStream

      @Deprecated public static TokenStream getTokenStream(Terms tpv) throws IOException
      Deprecated.
      Returns a token stream generated from a Terms. This can be used to feed the highlighter with a pre-parsed token stream. The Terms must have offsets available. If there are no positions available, all tokens will have position increments reflecting adjacent tokens, or coincident when terms share a start offset. If there are stopwords filtered from the index, you probably want to ensure term vectors have positions so that phrase queries won't match across stopwords.
      Throws:
      IllegalArgumentException - if no offsets are available
      IOException

    • getTokenStreamWithOffsets

      @Deprecated public static TokenStream getTokenStreamWithOffsets(IndexReader reader, int docId, String field) throws IOException
      Deprecated.
      Returns a TokenStream with positions and offsets constructed from field termvectors. If the field has no termvectors or offsets are not included in the termvector, return null. See getTokenStream(org.apache.lucene.index.Terms) for an explanation of what happens when positions aren't present.
      Parameters:
      reader - the IndexReader to retrieve term vectors from
      docId - the document to retrieve termvectors for
      field - the field to retrieve termvectors for
      Returns:
      a TokenStream, or null if offsets are not available
      Throws:
      IOException - If there is a low-level I/O error
      See Also:

    • getTokenStream

      @Deprecated public static TokenStream getTokenStream(IndexReader reader, int docId, String field, Analyzer analyzer) throws IOException
      Deprecated.
      Throws:
      IOException

    • getTokenStream

      @Deprecated public static TokenStream getTokenStream(Document doc, String field, Analyzer analyzer)
      Deprecated.

    • getTokenStream

      @Deprecated public static TokenStream getTokenStream(String field, String contents, Analyzer analyzer)
      Deprecated.