| /* |
| * 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.qpid.server.store; |
| |
| import java.io.File; |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.nio.channels.FileChannel; |
| import java.nio.channels.FileLock; |
| import java.nio.channels.OverlappingFileLockException; |
| import java.nio.file.Files; |
| import java.nio.file.Path; |
| |
| import com.fasterxml.jackson.databind.ObjectMapper; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.qpid.server.util.BaseAction; |
| import org.apache.qpid.server.util.FileHelper; |
| import org.apache.qpid.util.FileUtils; |
| |
| public abstract class AbstractJsonFileStore |
| { |
| private static final Logger LOGGER = LoggerFactory.getLogger(AbstractJsonFileStore.class); |
| |
| private final FileHelper _fileHelper; |
| |
| private String _directoryName; |
| private FileLock _fileLock; |
| private String _configFileName; |
| private String _backupFileName; |
| private String _tempFileName; |
| private String _lockFileName; |
| |
| protected AbstractJsonFileStore() |
| { |
| _fileHelper = new FileHelper(); |
| } |
| |
| abstract protected ObjectMapper getSerialisationObjectMapper(); |
| // abstract protected ObjectMapper getDeserialisationObjectMapper(); |
| |
| protected void setup(String name, |
| String storePath, |
| String posixFileAttributes, |
| Object initialData) |
| { |
| if(storePath == null) |
| { |
| throw new StoreException("Cannot determine path for configuration storage"); |
| } |
| File fileFromSettings = new File(storePath); |
| File parentFromSettings = fileFromSettings.getAbsoluteFile().getParentFile(); |
| boolean isFile = fileFromSettings.exists() && fileFromSettings.isFile(); |
| if(!isFile) |
| { |
| if(fileFromSettings.exists()) |
| { |
| isFile = false; |
| } |
| else if(fileFromSettings.getName().endsWith(File.separator)) |
| { |
| isFile = false; |
| } |
| else if(fileFromSettings.getName().endsWith(".json")) |
| { |
| isFile = true; |
| } |
| else if(parentFromSettings.isDirectory() && fileFromSettings.getName().contains(".")) |
| { |
| isFile = true; |
| } |
| } |
| if(isFile) |
| { |
| _directoryName = parentFromSettings.getAbsolutePath(); |
| _configFileName = fileFromSettings.getName(); |
| _backupFileName = fileFromSettings.getName() + ".bak"; |
| _tempFileName = fileFromSettings.getName() + ".tmp"; |
| |
| _lockFileName = fileFromSettings.getName() + ".lck"; |
| } |
| else |
| { |
| _directoryName = storePath; |
| _configFileName = name + ".json"; |
| _backupFileName = name + ".bak"; |
| _tempFileName = name + ".tmp"; |
| |
| _lockFileName = name + ".lck"; |
| } |
| |
| |
| checkDirectoryIsWritable(_directoryName); |
| getFileLock(); |
| |
| Path storeFile = new File(_directoryName, _configFileName).toPath(); |
| Path backupFile = new File(_directoryName, _backupFileName).toPath(); |
| if(!Files.exists(storeFile)) |
| { |
| if(!Files.exists(backupFile)) |
| { |
| try |
| { |
| storeFile = _fileHelper.createNewFile(storeFile, posixFileAttributes); |
| getSerialisationObjectMapper().writeValue(storeFile.toFile(), initialData); |
| } |
| catch (IOException e) |
| { |
| throw new StoreException("Could not write configuration file " + storeFile, e); |
| } |
| } |
| else |
| { |
| try |
| { |
| _fileHelper.atomicFileMoveOrReplace(backupFile, storeFile); |
| } |
| catch (IOException e) |
| { |
| throw new StoreException("Could not move backup to configuration file " + storeFile, e); |
| } |
| } |
| } |
| |
| try |
| { |
| Files.deleteIfExists(backupFile); |
| } |
| catch (IOException e) |
| { |
| throw new StoreException("Could not delete backup file " + backupFile, e); |
| } |
| } |
| |
| protected void cleanup() |
| { |
| releaseFileLock(); |
| } |
| |
| private void getFileLock() |
| { |
| File lockFile = new File(_directoryName, _lockFileName); |
| try |
| { |
| lockFile.createNewFile(); |
| lockFile.deleteOnExit(); |
| |
| @SuppressWarnings("resource") |
| FileOutputStream out = new FileOutputStream(lockFile); |
| FileChannel channel = out.getChannel(); |
| _fileLock = channel.tryLock(); |
| } |
| catch (IOException ioe) |
| { |
| throw new StoreException("Cannot create the lock file " + lockFile.getName(), ioe); |
| } |
| catch(OverlappingFileLockException e) |
| { |
| _fileLock = null; |
| } |
| |
| if(_fileLock == null) |
| { |
| throw new StoreException("Cannot get lock on file " + lockFile.getAbsolutePath() + ". Is another instance running?"); |
| } |
| } |
| |
| private void checkDirectoryIsWritable(String directoryName) |
| { |
| File dir = new File(directoryName); |
| if(dir.exists()) |
| { |
| if(dir.isDirectory()) |
| { |
| if(!dir.canWrite()) |
| { |
| throw new StoreException("Configuration path " + directoryName + " exists, but is not writable"); |
| } |
| |
| } |
| else |
| { |
| throw new StoreException("Configuration path " + directoryName + " exists, but is not a directory"); |
| } |
| } |
| else if(!dir.mkdirs()) |
| { |
| throw new StoreException("Cannot create directory " + directoryName); |
| } |
| } |
| |
| protected void save(final Object data) |
| { |
| try |
| { |
| Path tmpFile = new File(_directoryName, _tempFileName).toPath(); |
| _fileHelper.writeFileSafely( new File(_directoryName, _configFileName).toPath(), |
| new File(_directoryName, _backupFileName).toPath(), |
| tmpFile, |
| new BaseAction<File, IOException>() |
| { |
| @Override |
| public void performAction(File file) throws IOException |
| { |
| getSerialisationObjectMapper().writeValue(file, data); |
| } |
| }); |
| } |
| catch (IOException e) |
| { |
| throw new StoreException("Cannot save to store", e); |
| } |
| } |
| |
| private void releaseFileLock() |
| { |
| if (_fileLock != null) |
| { |
| try |
| { |
| _fileLock.release(); |
| _fileLock.channel().close(); |
| } |
| catch (IOException e) |
| { |
| throw new StoreException("Failed to release lock " + _fileLock, e); |
| } |
| finally |
| { |
| _fileLock = null; |
| } |
| } |
| } |
| |
| protected File getConfigFile() |
| { |
| return new File(_directoryName, _configFileName); |
| } |
| |
| protected void delete(final String storePath) |
| { |
| if (storePath != null) |
| { |
| if (LOGGER.isDebugEnabled()) |
| { |
| LOGGER.debug("Deleting store " + storePath); |
| } |
| |
| File configFile = new File(storePath); |
| if (!FileUtils.delete(configFile, true)) |
| { |
| LOGGER.info("Failed to delete the store at location " + storePath); |
| } |
| } |
| |
| _configFileName = null; |
| _directoryName = null; |
| } |
| } |