ReqOptSumScorer.java

package doser.lucene.query;

/*
 * 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 java.util.ArrayList;
import java.util.Collection;

import org.apache.lucene.search.Scorer;

/**
 * A Scorer for queries with a required part and an optional part. Delays
 * skipTo() on the optional part until a score() is needed. <br>
 * This <code>Scorer</code> implements {@link Scorer#advance(int)}.
 */
class ReqOptSumScorer extends Scorer {
	private Scorer optScorer;
	/**
	 * The scorers passed from the constructor. These are set to null as soon as
	 * their next() or skipTo() returns false.
	 */
	private final Scorer reqScorer;

	/**
	 * Construct a <code>ReqOptScorer</code>.
	 * 
	 * @param reqScorer
	 *            The required scorer. This must match.
	 * @param optScorer
	 *            The optional scorer. This is used for scoring only.
	 */
	public ReqOptSumScorer(final Scorer reqScorer, final Scorer optScorer) {
		super(reqScorer.getWeight());
		assert reqScorer != null;
		assert optScorer != null;
		this.reqScorer = reqScorer;
		this.optScorer = optScorer;
	}

	@Override
	public int advance(final int target) throws IOException {
		return reqScorer.advance(target);
	}

	@Override
	public long cost() {
		return reqScorer.cost();
	}

	@Override
	public int docID() {
		return reqScorer.docID();
	}

	@Override
	public int freq() throws IOException {
		// we might have deferred advance()
		this.score();
		return ((optScorer != null) && (optScorer.docID() == reqScorer.docID())) ? 2
				: 1;
	}

	@Override
	public Collection<ChildScorer> getChildren() {
		final ArrayList<ChildScorer> children = new ArrayList<ChildScorer>(2);
		children.add(new ChildScorer(reqScorer, "MUST"));
		children.add(new ChildScorer(optScorer, "SHOULD"));
		return children;
	}

	@Override
	public int nextDoc() throws IOException {
		return reqScorer.nextDoc();
	}

	/**
	 * Returns the score of the current document matching the query. Initially
	 * invalid, until {@link #nextDoc()} is called the first time.
	 * 
	 * @return The score of the required scorer, eventually increased by the
	 *         score of the optional scorer when it also matches the current
	 *         document.
	 */
	@Override
	public float score() throws IOException {
		// TODO: sum into a double and cast to float if we ever send required
		// clauses to BS1
		final int curDoc = reqScorer.docID();
		final float reqScore = reqScorer.score();
		if (optScorer == null) {
			return reqScore;
		}

		int optScorerDoc = optScorer.docID();
		if ((optScorerDoc < curDoc)
				&& ((optScorerDoc = optScorer.advance(curDoc)) == NO_MORE_DOCS)) {
			optScorer = null;
			return reqScore;
		}

		return optScorerDoc == curDoc ? reqScore + optScorer.score() : reqScore;
	}
}

// import java.io.IOException;
// import java.util.ArrayList;
// import java.util.Collection;
//
// import org.apache.lucene.search.Scorer;
//
//
// /**
// * A Scorer for queries with a required part and an optional part. Delays
// * skipTo() on the optional part until a score() is needed. <br>
// * This <code>Scorer</code> implements {@link Scorer#advance(int)}.
// */
// class ReqOptSumScorer extends Scorer {
// /**
// * The scorers passed from the constructor. These are set to null as soon as
// * their next() or skipTo() returns false.
// */
// private Scorer reqScorer;
// private Scorer optScorer;
//
// /**
// * Construct a <code>ReqOptScorer</code>.
// *
// * @param reqScorer
// * The required scorer. This must match.
// * @param optScorer
// * The optional scorer. This is used for scoring only.
// */
// public ReqOptSumScorer(Scorer reqScorer, Scorer optScorer) {
// super(reqScorer.getWeight());
// assert reqScorer != null;
// assert optScorer != null;
// this.reqScorer = reqScorer;
// this.optScorer = optScorer;
// }
//
// @Override
// public int nextDoc() throws IOException {
// return reqScorer.nextDoc();
// }
//
// @Override
// public int advance(int target) throws IOException {
// return reqScorer.advance(target);
// }
//
// @Override
// public int docID() {
// return reqScorer.docID();
// }
//
// /**
// * Returns the score of the current document matching the query. Initially
// * invalid, until {@link #nextDoc()} is called the first time.
// *
// * @return The score of the required scorer, eventually increased by the
// * score of the optional scorer when it also matches the current
// * document.
// */
// @Override
// public float score() throws IOException {
// // TODO: sum into a double and cast to float if we ever send required
// // clauses to BS1
// int curDoc = reqScorer.docID();
// float reqScore = reqScorer.score();
// if (optScorer == null) {
// return reqScore;
// }
//
// int optScorerDoc = optScorer.docID();
// if (optScorerDoc < curDoc
// && (optScorerDoc = optScorer.advance(curDoc)) == NO_MORE_DOCS) {
// optScorer = null;
// return reqScore;
// }
// return optScorerDoc == curDoc ? reqScore + optScorer.score() : reqScore;
// }
//
// @Override
// public int freq() throws IOException {
// // we might have deferred advance()
// score();
// return (optScorer != null && optScorer.docID() == reqScorer.docID()) ? 2
// : 1;
// }
//
// @Override
// public Collection<ChildScorer> getChildren() {
// ArrayList<ChildScorer> children = new ArrayList<ChildScorer>(2);
// children.add(new ChildScorer(reqScorer, "MUST"));
// children.add(new ChildScorer(optScorer, "SHOULD"));
// return children;
// }
// }