| package org.apache.lucene.index; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.util.List; |
| |
| |
| /** |
| * Common util methods for dealing with {@link IndexReader}s and {@link IndexReaderContext}s. |
| * |
| * @lucene.internal |
| */ |
| public final class ReaderUtil { |
| |
| private ReaderUtil() {} // no instance |
| |
| /** |
| * Walks up the reader tree and return the given context's top level reader |
| * context, or in other words the reader tree's root context. |
| */ |
| public static IndexReaderContext getTopLevelContext(IndexReaderContext context) { |
| while (context.parent != null) { |
| context = context.parent; |
| } |
| return context; |
| } |
| |
| /** |
| * Returns index of the searcher/reader for document <code>n</code> in the |
| * array used to construct this searcher/reader. |
| */ |
| public static int subIndex(int n, int[] docStarts) { // find |
| // searcher/reader for doc n: |
| int size = docStarts.length; |
| int lo = 0; // search starts array |
| int hi = size - 1; // for first element less than n, return its index |
| while (hi >= lo) { |
| int mid = (lo + hi) >>> 1; |
| int midValue = docStarts[mid]; |
| if (n < midValue) |
| hi = mid - 1; |
| else if (n > midValue) |
| lo = mid + 1; |
| else { // found a match |
| while (mid + 1 < size && docStarts[mid + 1] == midValue) { |
| mid++; // scan to last match |
| } |
| return mid; |
| } |
| } |
| return hi; |
| } |
| |
| /** |
| * Returns index of the searcher/reader for document <code>n</code> in the |
| * array used to construct this searcher/reader. |
| */ |
| public static int subIndex(int n, List<LeafReaderContext> leaves) { // find |
| // searcher/reader for doc n: |
| int size = leaves.size(); |
| int lo = 0; // search starts array |
| int hi = size - 1; // for first element less than n, return its index |
| while (hi >= lo) { |
| int mid = (lo + hi) >>> 1; |
| int midValue = leaves.get(mid).docBase; |
| if (n < midValue) |
| hi = mid - 1; |
| else if (n > midValue) |
| lo = mid + 1; |
| else { // found a match |
| while (mid + 1 < size && leaves.get(mid + 1).docBase == midValue) { |
| mid++; // scan to last match |
| } |
| return mid; |
| } |
| } |
| return hi; |
| } |
| } |