/*
 * 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
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 */
package org.apache.lucene.search.spans;


import java.io.IOException;
import java.util.List;

import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.ConjunctionDISI;
import org.apache.lucene.search.TwoPhaseIterator;

Common super class for multiple sub spans required in a document.
/** * Common super class for multiple sub spans required in a document. */
abstract class ConjunctionSpans extends Spans { final Spans[] subSpans; // in query order final DocIdSetIterator conjunction; // use to move to next doc with all clauses boolean atFirstInCurrentDoc; // a first start position is available in current doc for nextStartPosition boolean oneExhaustedInCurrentDoc; // one subspans exhausted in current doc ConjunctionSpans(List<Spans> subSpans) { if (subSpans.size() < 2) { throw new IllegalArgumentException("Less than 2 subSpans.size():" + subSpans.size()); } this.subSpans = subSpans.toArray(new Spans[subSpans.size()]); this.conjunction = ConjunctionDISI.intersectSpans(subSpans); this.atFirstInCurrentDoc = true; // ensure for doc -1 that start/end positions are -1 } @Override public int docID() { return conjunction.docID(); } @Override public long cost() { return conjunction.cost(); } @Override public int nextDoc() throws IOException { return (conjunction.nextDoc() == NO_MORE_DOCS) ? NO_MORE_DOCS : toMatchDoc(); } @Override public int advance(int target) throws IOException { return (conjunction.advance(target) == NO_MORE_DOCS) ? NO_MORE_DOCS : toMatchDoc(); } int toMatchDoc() throws IOException { oneExhaustedInCurrentDoc = false; while (true) { if (twoPhaseCurrentDocMatches()) { return docID(); } if (conjunction.nextDoc() == NO_MORE_DOCS) { return NO_MORE_DOCS; } } } abstract boolean twoPhaseCurrentDocMatches() throws IOException;
Return a TwoPhaseIterator view of this ConjunctionSpans.
/** * Return a {@link TwoPhaseIterator} view of this ConjunctionSpans. */
@Override public TwoPhaseIterator asTwoPhaseIterator() { float totalMatchCost = 0; // Compute the matchCost as the total matchCost/positionsCostant of the sub spans. for (Spans spans : subSpans) { TwoPhaseIterator tpi = spans.asTwoPhaseIterator(); if (tpi != null) { totalMatchCost += tpi.matchCost(); } else { totalMatchCost += spans.positionsCost(); } } final float matchCost = totalMatchCost; return new TwoPhaseIterator(conjunction) { @Override public boolean matches() throws IOException { return twoPhaseCurrentDocMatches(); } @Override public float matchCost() { return matchCost; } }; } @Override public float positionsCost() { throw new UnsupportedOperationException(); // asTwoPhaseIterator never returns null here. } public Spans[] getSubSpans() { return subSpans; } }