Package org.apache.lucene.search.highlight

# Interface Scorer

All Known Implementing Classes:
  `QueryScorer`, `QueryTermScorer`

public interface Scorer
A Scorer is responsible for scoring a stream of tokens. These token scores can then be used to compute `TextFragment` scores.

## Method Summary

Modifier and Type
Method
Description
`float`
`getFragmentScore()`
Called when the `Highlighter` has no more tokens for the current fragment - the Scorer returns the weighting it has derived for the most recent fragment, typically based on the results of `getTokenScore()`.
`float`
`getTokenScore()`
Called for each token in the current fragment.
`TokenStream`
`init(TokenStream tokenStream)`
Called to init the Scorer with a `TokenStream`.
`void`
`startFragment(TextFragment newFragment)`
Called when a new fragment is started for consideration.

## Method Details

### init

TokenStream init(TokenStream tokenStream) throws IOException
Called to init the Scorer with a `TokenStream`. You can grab references to the attributes you are interested in here and access them from `getTokenScore()`.

Parameters:
  `tokenStream` - the `TokenStream` that will be scored.
Returns:
  either a `TokenStream` that the Highlighter should continue using (eg if you read the tokenSream in this method) or null to continue using the same `TokenStream` that was passed in.
Throws:
  `IOException` - If there is a low-level I/O error

### startFragment

void startFragment(TextFragment newFragment)
Called when a new fragment is started for consideration.

Parameters:
  `newFragment` - the fragment that will be scored next

### getTokenScore

float getTokenScore()
Called for each token in the current fragment. The `Highlighter` will increment the `TokenStream` passed to init on every call.

Returns:
  a score which is passed to the `Highlighter` class to influence the mark-up of the text (this return value is NOT used to score the fragment)

### getFragmentScore

float getFragmentScore()
Called when the `Highlighter` has no more tokens for the current fragment - the Scorer returns the weighting it has derived for the most recent fragment, typically based on the results of `getTokenScore()`.