Package org.apache.lucene.search.highlight

Class TokenStreamFromTermVector

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.search.highlight.TokenStreamFromTermVector
All Implemented Interfaces:
Closeable, AutoCloseable
public final class TokenStreamFromTermVector extends TokenStream
TokenStream created from a term vector field. The term vector requires positions and/or offsets (either). If you want payloads add PayloadAttributeImpl (as you would normally) but don't assume the attribute is already added just because you know the term vector has payloads, since the first call to incrementToken() will observe if you asked for them and if not then won't get them. This TokenStream supports an efficient reset(), so there's no need to wrap with a caching impl.

The implementation will create an array of tokens indexed by token position. As long as there aren't massive jumps in positions, this is fine. And it assumes there aren't large numbers of tokens at the same position, since it adds them to a linked-list per position in O(N^2) complexity. When there aren't positions in the term vector, it divides the startOffset by 8 to use as a temporary substitute. In that case, tokens with the same startOffset will occupy the same final position; otherwise tokens become adjacent.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

  • Constructor Details

    • TokenStreamFromTermVector

      public TokenStreamFromTermVector(Terms vector, int maxStartOffset) throws IOException
      Constructor. The uninversion doesn't happen here; it's delayed till the first call to incrementToken.
      Parameters:
      vector - Terms that contains the data for creating the TokenStream. Must have positions and/or offsets.
      maxStartOffset - if a token's start offset exceeds this then the token is not added. -1 disables the limit.
      Throws:
      IOException

  • Method Details