Interface PositionIncrementAttribute

  • All Superinterfaces:
    All Known Implementing Classes:
    PackedTokenAttributeImpl, PositionIncrementAttributeImpl, Token

    public interface PositionIncrementAttribute
    extends Attribute
    Determines the position of this token relative to the previous Token in a TokenStream, used in phrase searching.

    The default value is one.

    Some common uses for this are:

    • Set it to zero to put multiple terms in the same position. This is useful if, e.g., a word has multiple stems. Searches for phrases including either stem will match. In this case, all but the first stem's increment should be set to zero: the increment of the first instance should be one. Repeating a token with an increment of zero can also be used to boost the scores of matches on that token.
    • Set it to values greater than one to inhibit exact phrase matches. If, for example, one does not want phrases to match across removed stop words, then one could build a stop word filter that removes stop words and also sets the increment to the number of stop words removed before each non-stop word. Then exact phrase queries will only match when the terms occur with no intervening stop words.
    See Also: