org.apache.lucene.search.spans.TermSpans.java Source code

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Here is the source code for org.apache.lucene.search.spans.TermSpans.java

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

import java.io.IOException;
import java.util.Objects;

import org.apache.lucene.index.PostingsEnum;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.LeafSimScorer;

/**
 * Expert:
 * Public for extension only.
 * This does not work correctly for terms that indexed at position Integer.MAX_VALUE.
 */
public class TermSpans extends Spans {
    protected final PostingsEnum postings;
    protected final Term term;
    protected int doc;
    protected int freq;
    protected int count;
    protected int position;
    protected boolean readPayload;
    private final float positionsCost;

    public TermSpans(LeafSimScorer scorer, PostingsEnum postings, Term term, float positionsCost) {
        this.postings = Objects.requireNonNull(postings);
        this.term = Objects.requireNonNull(term);
        this.doc = -1;
        this.position = -1;
        assert positionsCost > 0; // otherwise the TermSpans should not be created.
        this.positionsCost = positionsCost;
    }

    @Override
    public int nextDoc() throws IOException {
        doc = postings.nextDoc();
        if (doc != DocIdSetIterator.NO_MORE_DOCS) {
            freq = postings.freq();
            assert freq >= 1;
            count = 0;
        }
        position = -1;
        return doc;
    }

    @Override
    public int advance(int target) throws IOException {
        assert target > doc;
        doc = postings.advance(target);
        if (doc != DocIdSetIterator.NO_MORE_DOCS) {
            freq = postings.freq();
            assert freq >= 1;
            count = 0;
        }
        position = -1;
        return doc;
    }

    @Override
    public int docID() {
        return doc;
    }

    @Override
    public int nextStartPosition() throws IOException {
        if (count == freq) {
            assert position != NO_MORE_POSITIONS;
            return position = NO_MORE_POSITIONS;
        }
        int prevPosition = position;
        position = postings.nextPosition();
        assert position >= prevPosition : "prevPosition=" + prevPosition + " > position=" + position;
        assert position != NO_MORE_POSITIONS; // int endPosition not possible
        count++;
        readPayload = false;
        return position;
    }

    @Override
    public int startPosition() {
        return position;
    }

    @Override
    public int endPosition() {
        return (position == -1) ? -1 : (position != NO_MORE_POSITIONS) ? position + 1 : NO_MORE_POSITIONS;
    }

    @Override
    public int width() {
        return 0;
    }

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

    @Override
    public void collect(SpanCollector collector) throws IOException {
        collector.collectLeaf(postings, position, term);
    }

    @Override
    public float positionsCost() {
        return positionsCost;
    }

    @Override
    public String toString() {
        return "spans(" + term.toString() + ")@"
                + (doc == -1 ? "START"
                        : (doc == NO_MORE_DOCS) ? "ENDDOC"
                                : doc + " - " + (position == NO_MORE_POSITIONS ? "ENDPOS" : position));
    }

    public PostingsEnum getPostings() {
        return postings;
    }
}