| /* |
| * 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; |
| |
| /** |
| * Wraps an IntervalIterator and extends the bounds of its intervals |
| * |
| * Useful for specifying gaps in an ordered iterator; if you want to match |
| * `a b [2 spaces] c`, you can search for phrase(a, extended(b, 0, 2), c) |
| * |
| * An interval with prefix bounds extended by n will skip over matches that |
| * appear in positions lower than n |
| */ |
| class ExtendedIntervalIterator extends IntervalIterator { |
| |
| private final IntervalIterator in; |
| private final int before; |
| private final int after; |
| |
| private boolean positioned; |
| |
| /** |
| * Create a new ExtendedIntervalIterator |
| * @param in the iterator to wrap |
| * @param before the number of positions to extend before the delegated interval |
| * @param after the number of positions to extend beyond the delegated interval |
| */ |
| ExtendedIntervalIterator(IntervalIterator in, int before, int after) { |
| this.in = in; |
| this.before = before; |
| this.after = after; |
| } |
| |
| @Override |
| public int start() { |
| if (positioned == false) { |
| return -1; |
| } |
| int start = in.start(); |
| if (start == NO_MORE_INTERVALS) { |
| return NO_MORE_INTERVALS; |
| } |
| return Math.max(0, start - before); |
| } |
| |
| @Override |
| public int end() { |
| if (positioned == false) { |
| return -1; |
| } |
| int end = in.end(); |
| if (end == NO_MORE_INTERVALS) { |
| return NO_MORE_INTERVALS; |
| } |
| end += after; |
| if (end < 0 || end == NO_MORE_INTERVALS) { |
| // overflow |
| end = NO_MORE_INTERVALS - 1; |
| } |
| return end; |
| } |
| |
| @Override |
| public int gaps() { |
| return in.gaps(); |
| } |
| |
| @Override |
| public int nextInterval() throws IOException { |
| positioned = true; |
| in.nextInterval(); |
| return start(); |
| } |
| |
| @Override |
| public float matchCost() { |
| return in.matchCost(); |
| } |
| |
| @Override |
| public int docID() { |
| return in.docID(); |
| } |
| |
| @Override |
| public int nextDoc() throws IOException { |
| positioned = false; |
| return in.nextDoc(); |
| } |
| |
| @Override |
| public int advance(int target) throws IOException { |
| positioned = false; |
| return in.advance(target); |
| } |
| |
| @Override |
| public long cost() { |
| return in.cost(); |
| } |
| } |