/*
 * 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.queries.intervals;

import java.io.IOException;

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

A DocIdSetIterator that also allows iteration over matching intervals in a document. Once the iterator is positioned on a document by calling DocIdSetIterator.advance(int) or DocIdSetIterator.nextDoc(), intervals may be retrieved by calling nextInterval() until NO_MORE_INTERVALS is returned. The limits of the current interval are returned by start() and end(). When the iterator has been moved to a new document, but before nextInterval() has been called, both these methods return -1. Note that it is possible for a document to return NO_MORE_INTERVALS on the first call to nextInterval()
/** * A {@link DocIdSetIterator} that also allows iteration over matching * intervals in a document. * * Once the iterator is positioned on a document by calling {@link #advance(int)} * or {@link #nextDoc()}, intervals may be retrieved by calling {@link #nextInterval()} * until {@link #NO_MORE_INTERVALS} is returned. * * The limits of the current interval are returned by {@link #start()} and {@link #end()}. * When the iterator has been moved to a new document, but before {@link #nextInterval()} * has been called, both these methods return {@code -1}. * * Note that it is possible for a document to return {@link #NO_MORE_INTERVALS} * on the first call to {@link #nextInterval()} */
public abstract class IntervalIterator extends DocIdSetIterator {
When returned from nextInterval(), indicates that there are no more matching intervals on the current document
/** * When returned from {@link #nextInterval()}, indicates that there are no more * matching intervals on the current document */
public static final int NO_MORE_INTERVALS = Integer.MAX_VALUE;
The start of the current interval Returns -1 if nextInterval() has not yet been called and NO_MORE_INTERVALS once the iterator is exhausted.
/** * The start of the current interval * * Returns -1 if {@link #nextInterval()} has not yet been called and {@link #NO_MORE_INTERVALS} * once the iterator is exhausted. */
public abstract int start();
The end of the current interval Returns -1 if nextInterval() has not yet been called and NO_MORE_INTERVALS once the iterator is exhausted.
/** * The end of the current interval * * Returns -1 if {@link #nextInterval()} has not yet been called and {@link #NO_MORE_INTERVALS} * once the iterator is exhausted. */
public abstract int end();
The number of gaps within the current interval Note that this returns the number of gaps between the immediate sub-intervals of this interval, and does not include the gaps inside those sub-intervals. Should not be called before nextInterval(), or after it has returned NO_MORE_INTERVALS
/** * The number of gaps within the current interval * * Note that this returns the number of gaps between the immediate sub-intervals * of this interval, and does not include the gaps inside those sub-intervals. * * Should not be called before {@link #nextInterval()}, or after it has returned * {@link #NO_MORE_INTERVALS} */
public abstract int gaps();
The width of the current interval
/** * The width of the current interval */
public int width() { return end() - start() + 1; }
Advance the iterator to the next interval
Returns:the start of the next interval, or NO_MORE_INTERVALS if there are no more intervals on the current document
/** * Advance the iterator to the next interval * * @return the start of the next interval, or {@link IntervalIterator#NO_MORE_INTERVALS} if * there are no more intervals on the current document */
public abstract int nextInterval() throws IOException;
An indication of the average cost of iterating over all intervals in a document
See Also:
  • matchCost.matchCost()
/** * An indication of the average cost of iterating over all intervals in a document * * @see TwoPhaseIterator#matchCost() */
public abstract float matchCost(); @Override public String toString() { return docID() + ":[" + start() + "->" + end() + "]"; } }