package org.apache.lucene.search.highlight;

/**
 * Copyright 2002-2004 The Apache Software Foundation
 *
 * Licensed 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 org.apache.lucene.analysis.Token;

/**
 * Adds to the score for a fragment based on its tokens
 * 
 * @author mark@searcharea.co.uk
 */
public interface Scorer
{
	/**
	 * called when a new fragment is started for consideration
	 * 
	 * @param newFragment
	 */
	public void startFragment(TextFragment newFragment);

	/**
	 * Called for each token in the current fragment
	 * 
	 * @param token
	 *        The token to be scored
	 * @return 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)
	 */
	public float getTokenScore(Token token);

	/**
	 * 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 tokens passed to getTokenScore().
	 */
	public float getFragmentScore();

}
