/*
* 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 org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.TwoPhaseIterator;
Iterates through combinations of start/end positions per-doc.
Each start/end position represents a range of term positions within the current document.
These are enumerated in order, by increasing document number, within that by
increasing start position and finally by increasing end position.
/** Iterates through combinations of start/end positions per-doc.
* Each start/end position represents a range of term positions within the current document.
* These are enumerated in order, by increasing document number, within that by
* increasing start position and finally by increasing end position.
*/
public abstract class Spans extends DocIdSetIterator {
public static final int NO_MORE_POSITIONS = Integer.MAX_VALUE;
Returns the next start position for the current doc. There is always at least one start/end position per doc. After the last start/end position at the current doc this returns NO_MORE_POSITIONS. /**
* Returns the next start position for the current doc.
* There is always at least one start/end position per doc.
* After the last start/end position at the current doc this returns {@link #NO_MORE_POSITIONS}.
*/
public abstract int nextStartPosition() throws IOException;
Returns the start position in the current doc, or -1 when nextStartPosition was not yet called on the current doc. After the last start/end position at the current doc this returns NO_MORE_POSITIONS. /**
* Returns the start position in the current doc, or -1 when {@link #nextStartPosition} was not yet called on the current doc.
* After the last start/end position at the current doc this returns {@link #NO_MORE_POSITIONS}.
*/
public abstract int startPosition();
Returns the end position for the current start position, or -1 when nextStartPosition was not yet called on the current doc. After the last start/end position at the current doc this returns NO_MORE_POSITIONS. /**
* Returns the end position for the current start position, or -1 when {@link #nextStartPosition} was not yet called on the current doc.
* After the last start/end position at the current doc this returns {@link #NO_MORE_POSITIONS}.
*/
public abstract int endPosition();
Return the width of the match, which is typically used to sloppy freq. It is only legal
to call this method when the iterator is on a valid doc ID and positioned.
The return value must be positive, and lower values means that the match is
better.
/**
* Return the width of the match, which is typically used to sloppy freq. It is only legal
* to call this method when the iterator is on a valid doc ID and positioned.
* The return value must be positive, and lower values means that the match is
* better.
*/
public abstract int width();
Collect postings data from the leaves of the current Spans. This method should only be called after nextStartPosition(), and before NO_MORE_POSITIONS has been reached. Params: - collector – a SpanCollector
@lucene.experimental
/**
* Collect postings data from the leaves of the current Spans.
*
* This method should only be called after {@link #nextStartPosition()}, and before
* {@link #NO_MORE_POSITIONS} has been reached.
*
* @param collector a SpanCollector
*
* @lucene.experimental
*/
public abstract void collect(SpanCollector collector) throws IOException;
Return an estimation of the cost of using the positions of this Spans for any single document, but only after asTwoPhaseIterator returned null. Otherwise this method should not be called. The returned value is independent of the current document. @lucene.experimental
/**
* Return an estimation of the cost of using the positions of
* this {@link Spans} for any single document, but only after
* {@link #asTwoPhaseIterator} returned {@code null}.
* Otherwise this method should not be called.
* The returned value is independent of the current document.
*
* @lucene.experimental
*/
public abstract float positionsCost();
Optional method: Return a TwoPhaseIterator view of this Scorer. A return value of null indicates that two-phase iteration is not supported. See Also:
/**
* Optional method: Return a {@link TwoPhaseIterator} view of this
* {@link Scorer}. A return value of {@code null} indicates that
* two-phase iteration is not supported.
* @see Scorer#twoPhaseIterator()
*/
public TwoPhaseIterator asTwoPhaseIterator() {
return null;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
Class<? extends Spans> clazz = getClass();
sb.append(clazz.isAnonymousClass() ? clazz.getName() : clazz.getSimpleName());
sb.append("(doc=").append(docID());
sb.append(",start=").append(startPosition());
sb.append(",end=").append(endPosition());
sb.append(")");
return sb.toString();
}
Called before the current doc's frequency is calculated
/**
* Called before the current doc's frequency is calculated
*/
protected void doStartCurrentDoc() throws IOException {}
Called each time the scorer's SpanScorer is advanced during frequency calculation
/**
* Called each time the scorer's SpanScorer is advanced during frequency calculation
*/
protected void doCurrentSpans() throws IOException {}
}