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:
  - `TokenStreamFromTermVector`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static TokenStream`
  `getAnyTokenStream(IndexReader reader, int docId, String field, Analyzer analyzer)`
  Deprecated.
  `static TokenStream`
  `getAnyTokenStream(IndexReader reader, int docId, String field, Document document, Analyzer analyzer)`
  Deprecated.
  `static TokenStream`
  `getTermVectorTokenStreamOrNull(String field, Fields tvFields, int maxStartOffset)`
  Get a token stream by un-inverting the term vector.
  `static TokenStream`
  `getTokenStream(String field, String contents, Analyzer analyzer)`
  Deprecated.
  `static TokenStream`
  `getTokenStream(String field, Fields tvFields, String text, Analyzer analyzer, int maxStartOffset)`
  Get a token stream from either un-inverting a term vector if possible, or by analyzing the text.
  `static TokenStream`
  `getTokenStream(Document doc, String field, Analyzer analyzer)`
  Deprecated.
  `static TokenStream`
  `getTokenStream(IndexReader reader, int docId, String field, Analyzer analyzer)`
  Deprecated.
  `static TokenStream`
  `getTokenStream(Terms tpv)`
  Deprecated.
  `static TokenStream`
  `getTokenStream(Terms vector, boolean tokenPositionsGuaranteedContiguous)`
  Deprecated.
  `static TokenStream`
  `getTokenStreamWithOffsets(IndexReader reader, int docId, String field)`
  Deprecated.

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

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

- ## 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 `TermVectors.get(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 `TermVectors.get(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(org.apache.lucene.index.Terms)`

  - ### 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.