org.apache.lucene.analysis.tokenattributes
Interface PositionIncrementAttribute

All Superinterfaces:

Attribute

All Known Implementing Classes:

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:

DocsAndPositionsEnum

Method Summary

int	getPositionIncrement() Returns the position increment of this Token.
void	setPositionIncrement(int positionIncrement) Set the position increment.

Method Detail

setPositionIncrement

void setPositionIncrement(int positionIncrement)

Set the position increment. The default value is one.

Parameters:

positionIncrement - the distance from the prior term

Throws:

IllegalArgumentException - if positionIncrement is negative.

See Also:

getPositionIncrement()

getPositionIncrement

int getPositionIncrement()

Returns the position increment of this Token.

See Also:

setPositionIncrement(int)