| /* |
| * 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.cassandra.db.lifecycle; |
| |
| import java.io.File; |
| |
| import org.apache.cassandra.io.util.FileUtils; |
| import org.apache.cassandra.utils.CLibrary; |
| |
| /** |
| * Because a column family may have sstables on different disks and disks can |
| * be removed, we duplicate log files into many replicas so as to have a file |
| * in each folder where sstables exist. |
| * |
| * Each replica contains the exact same content but we do allow for final |
| * partial records in case we crashed after writing to one replica but |
| * before compliting the write to another replica. |
| * |
| * @see LogFile |
| */ |
| final class LogReplica |
| { |
| private final File file; |
| private int folderDescriptor; |
| |
| static LogReplica create(File folder, String fileName) |
| { |
| return new LogReplica(new File(fileName), CLibrary.tryOpenDirectory(folder.getPath())); |
| } |
| |
| static LogReplica open(File file) |
| { |
| return new LogReplica(file, CLibrary.tryOpenDirectory(file.getParentFile().getPath())); |
| } |
| |
| LogReplica(File file, int folderDescriptor) |
| { |
| this.file = file; |
| this.folderDescriptor = folderDescriptor; |
| } |
| |
| File file() |
| { |
| return file; |
| } |
| |
| void append(LogRecord record) |
| { |
| boolean existed = exists(); |
| FileUtils.appendAndSync(file, record.toString()); |
| |
| // If the file did not exist before appending the first |
| // line, then sync the folder as well since now it must exist |
| if (!existed) |
| syncFolder(); |
| } |
| |
| void syncFolder() |
| { |
| if (folderDescriptor >= 0) |
| CLibrary.trySync(folderDescriptor); |
| } |
| |
| void delete() |
| { |
| LogTransaction.delete(file); |
| syncFolder(); |
| } |
| |
| boolean exists() |
| { |
| return file.exists(); |
| } |
| |
| void close() |
| { |
| if (folderDescriptor >= 0) |
| { |
| CLibrary.tryCloseFD(folderDescriptor); |
| folderDescriptor = -1; |
| } |
| } |
| |
| @Override |
| public String toString() |
| { |
| return String.format("[%s] ", file); |
| } |
| } |