Java tutorial
/* * 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.statelib.impl.rocksdb.checkpoint.fs; import com.google.common.collect.Lists; import com.google.common.io.MoreFiles; import com.google.common.io.RecursiveDeleteOption; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.nio.file.Files; import java.nio.file.Paths; import java.nio.file.StandardCopyOption; import java.util.Collections; import java.util.List; import org.apache.bookkeeper.statelib.api.checkpoint.CheckpointStore; /** * Filesystem based checkpoint factory. */ public class FSCheckpointManager implements CheckpointStore { private final File rootPath; public FSCheckpointManager(File rootPath) { this.rootPath = rootPath; } private File getFullyQualifiedPath(String filePath) { return new File(rootPath, filePath); } @Override public List<String> listFiles(String filePath) throws IOException { String[] files = getFullyQualifiedPath(filePath).list(); if (null == files) { return Collections.emptyList(); } return Lists.newArrayList(files); } @Override public boolean fileExists(String filePath) throws IOException { return getFullyQualifiedPath(filePath).exists(); } @Override public long getFileLength(String filePath) throws IOException { return getFullyQualifiedPath(filePath).length(); } @Override public InputStream openInputStream(String filePath) throws IOException { return new FileInputStream(getFullyQualifiedPath(filePath)); } @Override public OutputStream openOutputStream(String filePath) throws IOException { return new FileOutputStream(getFullyQualifiedPath(filePath)); } @Override public void rename(String srcPath, String destPath) throws IOException { Files.move(Paths.get(getFullyQualifiedPath(srcPath).getAbsolutePath()), Paths.get(getFullyQualifiedPath(destPath).getAbsolutePath()), StandardCopyOption.ATOMIC_MOVE); } @Override public void deleteRecursively(String srcPath) throws IOException { MoreFiles.deleteRecursively(Paths.get(getFullyQualifiedPath(srcPath).getAbsolutePath()), RecursiveDeleteOption.ALLOW_INSECURE); } @Override public void delete(String srcPath) throws IOException { Files.delete(Paths.get(getFullyQualifiedPath(srcPath).getAbsolutePath())); } @Override public void createDirectories(String srcPath) throws IOException { Files.createDirectories(Paths.get(getFullyQualifiedPath(srcPath).getAbsolutePath())); } @Override public void close() { // no-op } }