org.apache.bookkeeper.util.LedgerDirUtil Maven / Gradle / Ivy
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*
* 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.bookkeeper.util;
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.lang3.tuple.Pair;
public class LedgerDirUtil {
public static final Pattern FILE_PATTERN = Pattern.compile("^([0-9a-fA-F]+)\\.log$");
public static final Pattern COMPACTED_FILE_PATTERN =
Pattern.compile("^([0-9a-fA-F]+)\\.log\\.([0-9a-fA-F]+)\\.compacted$");
public static List logIdsInDirectory(File directory) {
List ids = new ArrayList<>();
if (directory.exists() && directory.isDirectory()) {
File[] files = directory.listFiles();
if (files != null && files.length > 0) {
for (File f : files) {
Matcher m = FILE_PATTERN.matcher(f.getName());
if (m.matches()) {
int logId = Integer.parseUnsignedInt(m.group(1), 16);
ids.add(logId);
}
}
}
}
return ids;
}
public static List compactedLogIdsInDirectory(File directory) {
List ids = new ArrayList<>();
if (directory.exists() && directory.isDirectory()) {
File[] files = directory.listFiles();
if (files != null && files.length > 0) {
for (File f : files) {
Matcher m = COMPACTED_FILE_PATTERN.matcher(f.getName());
if (m.matches()) {
int logId = Integer.parseUnsignedInt(m.group(1), 16);
ids.add(logId);
}
}
}
}
return ids;
}
/**
* O(nlogn) algorithm to find largest contiguous gap between
* integers in a passed list. n should be relatively small.
* Entry logs should be about 1GB in size, so even if the node
* stores a PB, there should be only 1000000 entry logs.
*/
public static Pair findLargestGap(List currentIds) {
if (currentIds.isEmpty()) {
return Pair.of(0, Integer.MAX_VALUE);
}
Collections.sort(currentIds);
int nextIdCandidate = 0;
int maxIdCandidate = currentIds.get(0);
int maxGap = maxIdCandidate - nextIdCandidate;
for (int i = 0; i < currentIds.size(); i++) {
int gapStart = currentIds.get(i) + 1;
int j = i + 1;
int gapEnd = Integer.MAX_VALUE;
if (j < currentIds.size()) {
gapEnd = currentIds.get(j);
}
int gapSize = gapEnd - gapStart;
if (gapSize > maxGap) {
maxGap = gapSize;
nextIdCandidate = gapStart;
maxIdCandidate = gapEnd;
}
}
return Pair.of(nextIdCandidate, maxIdCandidate);
}
}