- /**
- * 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.hadoop.contrib.index.lucene;
- import java.io.IOException;
- import org.apache.lucene.store.Directory;
- /**
- * This class copies some methods from Lucene's SegmentInfos since that class
- * is not public.
- */
- public final class LuceneUtil {
- static final class IndexFileNames {
- /** Name of the index segment file */
- static final String SEGMENTS = "segments";
- /** Name of the generation reference file name */
- static final String SEGMENTS_GEN = "segments.gen";
- }
- /**
- * Check if the file is a segments_N file
- * @param name
- * @return true if the file is a segments_N file
- */
- public static boolean isSegmentsFile(String name) {
- return name.startsWith(IndexFileNames.SEGMENTS)
- && !name.equals(IndexFileNames.SEGMENTS_GEN);
- }
- /**
- * Check if the file is the segments.gen file
- * @param name
- * @return true if the file is the segments.gen file
- */
- public static boolean isSegmentsGenFile(String name) {
- return name.equals(IndexFileNames.SEGMENTS_GEN);
- }
- /**
- * Get the generation (N) of the current segments_N file in the directory.
- *
- * @param directory -- directory to search for the latest segments_N file
- */
- public static long getCurrentSegmentGeneration(Directory directory)
- throws IOException {
- String[] files = directory.list();
- if (files == null)
- throw new IOException("cannot read directory " + directory
- + ": list() returned null");
- return getCurrentSegmentGeneration(files);
- }
- /**
- * Get the generation (N) of the current segments_N file from a list of
- * files.
- *
- * @param files -- array of file names to check
- */
- public static long getCurrentSegmentGeneration(String[] files) {
- if (files == null) {
- return -1;
- }
- long max = -1;
- for (int i = 0; i < files.length; i++) {
- String file = files[i];
- if (file.startsWith(IndexFileNames.SEGMENTS)
- && !file.equals(IndexFileNames.SEGMENTS_GEN)) {
- long gen = generationFromSegmentsFileName(file);
- if (gen > max) {
- max = gen;
- }
- }
- }
- return max;
- }
- /**
- * Parse the generation off the segments file name and return it.
- */
- public static long generationFromSegmentsFileName(String fileName) {
- if (fileName.equals(IndexFileNames.SEGMENTS)) {
- return 0;
- } else if (fileName.startsWith(IndexFileNames.SEGMENTS)) {
- return Long.parseLong(
- fileName.substring(1 + IndexFileNames.SEGMENTS.length()),
- Character.MAX_RADIX);
- } else {
- throw new IllegalArgumentException("fileName "" + fileName
- + "" is not a segments file");
- }
- }
- }