package org.apache.lucene.search.highlight;
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.io.IOException;
import org.apache.lucene.analysis.TokenStream;
/**
* A Scorer is responsible for scoring a stream of tokens. These token scores
* can then be used to compute {@link TextFragment} scores.
*/
public interface Scorer {
/**
* Called to init the Scorer with a {@link TokenStream}. You can grab references to
* the attributes you are interested in here and access them from {@link #getTokenScore()}.
*
* @param tokenStream the {@link TokenStream} that will be scored.
* @return either a {@link TokenStream} that the Highlighter should continue using (eg
* if you read the tokenSream in this method) or null to continue
* using the same {@link TokenStream} that was passed in.
* @throws IOException
*/
public TokenStream init(TokenStream tokenStream) throws IOException;
/**
* Called when a new fragment is started for consideration.
*
* @param newFragment the fragment that will be scored next
*/
public void startFragment(TextFragment newFragment);
/**
* Called for each token in the current fragment. The {@link Highlighter} will
* increment the {@link TokenStream} passed to init on every call.
*
* @return a score which is passed to the {@link Highlighter} class to influence the
* mark-up of the text (this return value is NOT used to score the
* fragment)
*/
public float getTokenScore();
/**
* Called when the {@link 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 {@link #getTokenScore()}.
*
*/
public float getFragmentScore();
}