File System Utilities

/**
 * Hadoop FileSystem utility functions
 * Provides conversion utilities and FileSystem management
 */
public class HadoopFSUtils {
    
    /** Prepare Hadoop configuration with Hudi-specific settings */
    public static Configuration prepareHadoopConf(Configuration conf);
    
    /** Get storage configuration from Hadoop configuration */
    public static StorageConfiguration<Configuration> getStorageConf(Configuration conf);
    
    /** Get default storage configuration */
    public static StorageConfiguration<Configuration> getStorageConf();
    
    /** Get storage configuration with copy of Hadoop configuration */
    public static StorageConfiguration<Configuration> getStorageConfWithCopy(Configuration conf);
    
    /** Get FileSystem for path string with storage configuration */
    public static <T> FileSystem getFs(String pathStr, StorageConfiguration<T> storageConf);
    
    /** Get FileSystem for Hadoop Path with storage configuration */
    public static <T> FileSystem getFs(Path path, StorageConfiguration<T> storageConf);
    
    /** Get FileSystem for path string with Hadoop configuration */
    public static FileSystem getFs(String pathStr, Configuration conf);
    
    /** Get FileSystem for Hadoop Path with configuration */
    public static FileSystem getFs(Path path, Configuration conf);
    
    /** Get FileSystem for StoragePath with configuration */
    public static FileSystem getFs(StoragePath path, Configuration conf);
    
    /** Get FileSystem with newCopy option */
    public static <T> FileSystem getFs(String pathStr, StorageConfiguration<T> storageConf, boolean newCopy);
    
    /** Get FileSystem for Path with newCopy option */
    public static <T> FileSystem getFs(Path path, StorageConfiguration<T> storageConf, boolean newCopy);
    
    /** Get FileSystem with local default option */
    public static FileSystem getFs(String pathStr, Configuration conf, boolean localByDefault);
    
    /** Add scheme to local path if missing */
    public static Path addSchemeIfLocalPath(String path);
    
    /** Convert StoragePath to Hadoop Path */
    public static Path convertToHadoopPath(StoragePath path);
    
    /** Convert Hadoop Path to StoragePath */
    public static StoragePath convertToStoragePath(Path path);
    
    /** Convert FileStatus to StoragePathInfo */
    public static StoragePathInfo convertToStoragePathInfo(FileStatus fileStatus);
    
    /** Convert FileStatus to StoragePathInfo with locations */
    public static StoragePathInfo convertToStoragePathInfo(FileStatus fileStatus, String[] locations);
    
    /** Convert StoragePathInfo to Hadoop FileStatus */
    public static FileStatus convertToHadoopFileStatus(StoragePathInfo pathInfo);
    
    /** Get FSDataInputStream with buffer settings */
    public static FSDataInputStream getFSDataInputStream(FileSystem fs, StoragePath path, int bufferSize, boolean wrapStream);
    
    /** Check if FileSystem is Google Cloud Storage */
    public static boolean isGCSFileSystem(FileSystem fs);
    
    /** Check if FileSystem is Cloudera Hadoop Distribution */
    public static boolean isCHDFileSystem(FileSystem fs);
    
    /** Register file system for path */
    public static Configuration registerFileSystem(StoragePath file, Configuration conf);
    
    /** Get file size from FileSystem */
    public static long getFileSize(FileSystem fs, Path path);
    
    /** Get relative partition path */
    public static String getRelativePartitionPath(Path basePath, Path fullPartitionPath);
    
    /** Get file ID from log path */
    public static String getFileIdFromLogPath(Path path);
    
    /** Get delta commit time from log path */
    public static String getDeltaCommitTimeFromLogPath(Path path);
    
    /** Get file ID from file path */
    public static String getFileIdFromFilePath(Path filePath);
    
    /** Check if path is base file */
    public static boolean isBaseFile(Path path);
    
    /** Check if path is log file */
    public static boolean isLogFile(Path logPath);
    
    /** Check if path is data file */
    public static boolean isDataFile(Path path);
    
    /** Get all data files in partition */
    public static FileStatus[] getAllDataFilesInPartition(FileSystem fs, Path partitionPath);
    
    /** Construct absolute path in Hadoop */
    public static Path constructAbsolutePathInHadoopPath(String basePath, String relativePartitionPath);
    
    /** Get DFS full partition path */
    public static String getDFSFullPartitionPath(FileSystem fs, Path fullPartitionPath);
    
    /** Parallelize files processing */
    public static <T> Map<String, T> parallelizeFilesProcess(Configuration configuration, List<String> filePathList, 
                                                            SerializableFunction<String, T> func, int parallelism);
    
    /** Get file status at level */
    public static List<FileStatus> getFileStatusAtLevel(Configuration configuration, Path path, int level, 
                                                       int parallelism, String[] subPathFilters, List<Path> subPaths);
    
    /** Delete files in parallel */
    public static Map<String, Boolean> deleteFilesParallelize(Configuration configuration, List<String> filePathList, 
                                                              int parallelism);
}

/**
 * Add scheme to local path if missing
 * @param path - Path string that may need scheme
 * @return Hadoop Path with proper scheme
 */
public static Path addSchemeIfLocalPath(String path);

/**
 * Convert StoragePath to Hadoop Path
 * @param path - Hudi StoragePath
 * @return Equivalent Hadoop Path
 */
public static Path convertToHadoopPath(StoragePath path);

/**
 * Convert Hadoop Path to StoragePath
 * @param path - Hadoop Path
 * @return Equivalent Hudi StoragePath
 */
public static StoragePath convertToStoragePath(Path path);

/**
 * Convert Hadoop FileStatus to StoragePathInfo
 * @param fileStatus - Hadoop FileStatus
 * @return Equivalent StoragePathInfo
 */
public static StoragePathInfo convertToStoragePathInfo(FileStatus fileStatus);

/**
 * Convert StoragePathInfo to Hadoop FileStatus
 * @param pathInfo - Hudi StoragePathInfo
 * @return Equivalent Hadoop FileStatus
 */
public static FileStatus convertToHadoopFileStatus(StoragePathInfo pathInfo);

/**
 * Convert HoodiePath to Hadoop Path (legacy)
 * @param path - Legacy HoodiePath
 * @return Hadoop Path
 */
public static Path toPath(HoodiePath path);

/**
 * Convert Hadoop Path to HoodiePath (legacy)
 * @param path - Hadoop Path
 * @return Legacy HoodiePath
 */
public static HoodiePath fromPath(Path path);

/**
 * Convert HoodieFSPermission to Hadoop FsPermission
 * @param fsPermission - Hudi file system permission
 * @return Hadoop FsPermission
 */
public static FsPermission toFSPermission(HoodieFSPermission fsPermission);

/**
 * Convert Hadoop FsPermission to HoodieFSPermission
 * @param fsPermission - Hadoop file system permission
 * @return Hudi HoodieFSPermission
 */
public static HoodieFSPermission fromFSPermission(FsPermission fsPermission);

/**
 * Convert Hadoop FileStatus to HoodieFileStatus
 * @param fileStatus - Hadoop FileStatus
 * @return Hudi HoodieFileStatus
 */
public static HoodieFileStatus fromFileStatus(FileStatus fileStatus);

/**
 * Get FSDataInputStream with buffering options
 * @param fs - Hadoop FileSystem
 * @param filePath - Storage path to read
 * @param bufferSize - Buffer size for reading
 * @param wrapStream - Whether to wrap the stream
 * @return FSDataInputStream for reading
 */
public static FSDataInputStream getFSDataInputStream(FileSystem fs, StoragePath filePath, 
                                                    int bufferSize, boolean wrapStream);

/**
 * Get file size from FileSystem
 * @param fs - Hadoop FileSystem
 * @param path - Hadoop Path to check
 * @return File size in bytes
 */
public static long getFileSize(FileSystem fs, Path path);

/**
 * Get relative partition path
 * @param basePath - Base path of the table
 * @param fullPartitionPath - Full path to the partition
 * @return Relative partition path string
 */
public static String getRelativePartitionPath(Path basePath, Path fullPartitionPath);

/**
 * Register FileSystem for the given file
 * @param file - Storage path for file
 * @param conf - Hadoop configuration
 * @return Updated configuration with registered FileSystem
 */
public static Configuration registerFileSystem(StoragePath file, Configuration conf);

/**
 * Check if FileSystem is Google Cloud Storage
 * @param fs - FileSystem to check
 * @return true if GCS FileSystem
 */
public static boolean isGCSFileSystem(FileSystem fs);

/**
 * Check if FileSystem is Cloudera CHD FileSystem
 * @param fs - FileSystem to check
 * @return true if CHD FileSystem
 */
public static boolean isCHDFileSystem(FileSystem fs);

/**
 * Extract file ID from log file path
 * @param path - Hadoop Path to log file
 * @return File ID string
 */
public static String getFileIdFromLogPath(Path path);

/**
 * Extract delta commit time from log file path
 * @param path - Hadoop Path to log file
 * @return Delta commit time string
 */
public static String getDeltaCommitTimeFromLogPath(Path path);

/**
 * Extract file ID from any file path
 * @param filePath - Hadoop Path to file
 * @return File ID string
 */
public static String getFileIdFromFilePath(Path filePath);

/**
 * Check if path points to a base file
 * @param path - Hadoop Path to check
 * @return true if base file
 */
public static boolean isBaseFile(Path path);

/**
 * Check if path points to a log file
 * @param logPath - Hadoop Path to check
 * @return true if log file
 */
public static boolean isLogFile(Path logPath);

/**
 * Check if path points to a data file (base or log)
 * @param path - Hadoop Path to check
 * @return true if data file
 */
public static boolean isDataFile(Path path);

/**
 * Get all data files in a partition
 * @param fs - Hadoop FileSystem
 * @param partitionPath - Path to partition directory
 * @return Array of FileStatus for data files
 */
public static FileStatus[] getAllDataFilesInPartition(FileSystem fs, Path partitionPath);

/**
 * Recover DFS file lease for write operations
 * @param dfs - DistributedFileSystem instance
 * @param p - Path to file with lease issues
 * @return true if lease recovery succeeded
 */
public static boolean recoverDFSFileLease(DistributedFileSystem dfs, Path p);

/**
 * Wrapper FileSystem with consistency guarantees
 * Ensures file operations respect consistency requirements
 */
public class HoodieWrapperFileSystem extends FileSystem {
    
    /** Create wrapper with FileSystem and consistency guard */
    public HoodieWrapperFileSystem(FileSystem fs, ConsistencyGuard consistencyGuard);
    
    // Extends all FileSystem interface methods with consistency checks
    // All standard FileSystem operations are available with consistency guarantees
}

/**
 * FileSystem wrapper with retry capabilities
 * Automatically retries failed operations with configurable parameters
 */
public class HoodieRetryWrapperFileSystem extends FileSystem {
    
    /** Create retry wrapper with configuration */
    public HoodieRetryWrapperFileSystem(FileSystem fs, long maxRetryIntervalMs, 
                                       int maxRetryNumbers, long initialRetryIntervalMs, 
                                       String retryExceptions);
    
    // Extends all FileSystem interface methods with retry logic
    // Operations are automatically retried on transient failures
}

/**
 * Seekable data input stream for Hadoop
 * Provides random access capabilities for file reading
 */
public class HadoopSeekableDataInputStream implements SeekableDataInputStream {
    
    /** Create seekable stream from FSDataInputStream */
    public HadoopSeekableDataInputStream(FSDataInputStream fsDataInputStream);
    
    /** Read single byte */
    public int read();
    
    /** Read bytes into buffer */
    public int read(byte[] b, int off, int len);
    
    /** Seek to specific position */
    public void seek(long pos);
    
    /** Get current position */
    public long getPos();
    
    /** Close the stream */
    public void close();
}

/**
 * Serializable wrapper for FileStatus
 * Allows FileStatus to be serialized for distributed operations
 */
public class HoodieSerializableFileStatus implements Serializable {
    // Standard FileStatus interface methods with Serializable support
    public Path getPath();
    public long getLen();
    public boolean isDirectory();
    public long getModificationTime();
    public FsPermission getPermission();
}

/**
 * Path implementation with caching capabilities
 * Optimizes path operations through intelligent caching
 */
public class CachingPath extends Path {
    // Extended Path functionality with caching optimizations
    public CachingPath(String pathString);
    public CachingPath(Path parent, String child);
}

import org.apache.hudi.hadoop.fs.HadoopFSUtils;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.Configuration;

// Basic FileSystem operations
Configuration conf = new Configuration();
conf.set("fs.defaultFS", "hdfs://namenode:8020");

// Get FileSystem instance
FileSystem fs = HadoopFSUtils.getFs("hdfs://namenode:8020/data", conf);

// Path conversions
StoragePath storagePath = new StoragePath("hdfs://namenode:8020/data/table");
Path hadoopPath = HadoopFSUtils.convertToHadoopPath(storagePath);
StoragePath backToStorage = HadoopFSUtils.convertToStoragePath(hadoopPath);

// File identification
Path logFile = new Path("/data/table/.hoodie/20231201120000.deltacommit.log");
boolean isLog = HadoopFSUtils.isLogFile(logFile);
String fileId = HadoopFSUtils.getFileIdFromLogPath(logFile);
String commitTime = HadoopFSUtils.getDeltaCommitTimeFromLogPath(logFile);

// Get all data files in partition
Path partitionPath = new Path("/data/table/year=2023/month=12");
FileStatus[] dataFiles = HadoopFSUtils.getAllDataFilesInPartition(fs, partitionPath);

// Using wrapper FileSystem with consistency
ConsistencyGuard guard = new OptimisticConsistencyGuard(fs, conf);
HoodieWrapperFileSystem wrapperFs = new HoodieWrapperFileSystem(fs, guard);

// Using retry wrapper
HoodieRetryWrapperFileSystem retryFs = new HoodieRetryWrapperFileSystem(
    fs, 
    5000L, // maxRetryIntervalMs
    3,     // maxRetryNumbers  
    1000L, // initialRetryIntervalMs
    "java.io.IOException" // retryExceptions
);

// Seekable stream operations
Path dataFile = new Path("/data/table/file.parquet");
FSDataInputStream fsInput = fs.open(dataFile);
HadoopSeekableDataInputStream seekableInput = new HadoopSeekableDataInputStream(fsInput);

// Random access reading
seekableInput.seek(1024); // Seek to position 1024
int data = seekableInput.read();
long currentPos = seekableInput.getPos();
seekableInput.close();