File System Integration

/**
 * Primary factory for file system-based tables
 * Implements dynamic table factory pattern for Flink SQL integration
 */
class FileSystemTableFactory 
    implements DynamicTableSourceFactory, DynamicTableSinkFactory {
    
    /** Create dynamic table source for reading from file systems */
    DynamicTableSource createDynamicTableSource(Context context);
    
    /** Create dynamic table sink for writing to file systems */
    DynamicTableSink createDynamicTableSink(Context context);
    
    /** Get factory identifier */
    String factoryIdentifier();
    
    /** Get required context properties */
    Set<ConfigOption<?>> requiredOptions();
    
    /** Get optional context properties */
    Set<ConfigOption<?>> optionalOptions();
}

/** Main table source implementation for file systems */
class FileSystemTableSource extends AbstractFileSystemTable 
    implements ScanTableSource, PartitionableTableSource, LimitableTableSource {
    
    FileSystemTableSource(
        ObjectIdentifier tableIdentifier,
        CatalogTable catalogTable,
        Map<String, String> properties,
        ReadableConfig tableOptions
    );
    
    /** Get scan runtime provider */
    ScanRuntimeProvider getScanRuntimeProvider(ScanContext scanContext);
    
    /** Apply limit push-down optimization */
    Result applyLimit(long limit);
}

/** Main table sink implementation for file systems */
class FileSystemTableSink extends AbstractFileSystemTable 
    implements DynamicTableSink, PartitionableTableSink {
    
    FileSystemTableSink(
        ObjectIdentifier tableIdentifier,
        CatalogTable catalogTable,
        Map<String, String> properties,
        ReadableConfig tableOptions
    );
    
    /** Get sink runtime provider */
    SinkRuntimeProvider getSinkRuntimeProvider(Context context);
    
    /** Apply static partition insertion */
    void applyStaticPartition(Map<String, String> partition);
}

/** Base class for file system tables */
abstract class AbstractFileSystemTable implements DynamicTableSource, DynamicTableSink {
    /** Get table schema */
    TableSchema getTableSchema();
    
    /** Get partition keys */
    List<String> getPartitionKeys();
    
    /** Copy table with new properties */
    abstract AbstractFileSystemTable copy(Map<String, String> newProperties);
}

/**
 * Factory for file system instances
 * Enables support for different storage systems (HDFS, S3, local, etc.)
 */
interface FileSystemFactory extends Serializable {
    /** Create file system instance */
    FileSystem create(URI fsUri) throws IOException;
}

/**
 * Interface for computing partitions
 * Determines which partition a record belongs to
 */
interface PartitionComputer<T> {
    /** Compute partition path for given record */
    String generatePartValues(T record) throws Exception;
    
    /** Get partition field names */
    String[] getPartitionFieldNames();
}

/**
 * Interface for writing partitioned data
 * Handles the actual writing of records to partition-specific locations
 */
interface PartitionWriter<T> {
    /** Write a record to the appropriate partition */
    void write(T record) throws Exception;
    
    /** Close the writer and finalize writes */
    void close() throws Exception;
    
    /** Get commit information */
    List<PartitionCommitInfo> getCommitInfos();
}

/**
 * Interface for reading partitions
 * Provides partition-aware reading capabilities
 */
interface PartitionReader<P, OUT> {
    /** Read partition data */
    OUT read(P partition) throws Exception;
    
    /** Get partition metadata */
    P[] getPartitions() throws Exception;
}

/** Partition computer implementation for row data */
class RowDataPartitionComputer implements PartitionComputer<RowData> {
    RowDataPartitionComputer(
        String defaultPartValue,
        String[] partitionColumns,
        LogicalType[] partitionTypes,
        String[] fieldNames,
        LogicalType[] fieldTypes
    );
}

/** Dynamic partition writer implementation */
class DynamicPartitionWriter<T> implements PartitionWriter<T> {
    DynamicPartitionWriter(
        PartitionComputer<T> computer,
        PartitionWriterFactory<T> factory,
        FileSystemCommitter committer
    );
    
    /** Write record to dynamically determined partition */
    void write(T record) throws Exception;
}

/** Grouped partition writer implementation */
class GroupedPartitionWriter<T> implements PartitionWriter<T> {
    GroupedPartitionWriter(
        PartitionComputer<T> computer,
        PartitionWriterFactory<T> factory,
        long maxOpenWriters
    );
    
    /** Write record using grouped partitioning strategy */
    void write(T record) throws Exception;
}

/** Single directory writer implementation */
class SingleDirectoryWriter<T> implements PartitionWriter<T> {
    SingleDirectoryWriter(
        OutputFormatFactory<T> formatFactory,
        Path outputDir,
        String filePrefix
    );
    
    /** Write record to single directory */
    void write(T record) throws Exception;
}

/**
 * Factory for partition writers
 * Creates partition-specific writers on demand
 */
interface PartitionWriterFactory<T> extends Serializable {
    /** Create writer for specific partition */
    PartitionWriter<T> createWriter(String partition) throws IOException;
}

/**
 * Interface for partition commit strategies
 * Determines when and how partitions should be committed
 */
interface PartitionCommitPolicy extends Serializable {
    /** Check if partition should be committed */
    boolean shouldCommit(Context context) throws Exception;
    
    /** Execute the commit operation */
    void commit(Context context) throws Exception;
    
    /** Context for commit operations */
    interface Context {
        /** Get partition path */
        String partition();
        
        /** Get partition commit trigger context */
        PartitionCommitTrigger.Context commitContext();
    }
}

/** Metastore-based commit policy implementation */
class MetastoreCommitPolicy implements PartitionCommitPolicy {
    MetastoreCommitPolicy(
        TableMetaStoreFactory metaStoreFactory,
        ObjectIdentifier tableIdentifier,
        List<String> partitionKeys
    );
}

/**
 * Factory for output formats
 * Enables integration with different file formats (Parquet, ORC, CSV, etc.)
 */
interface OutputFormatFactory<T> extends Serializable {
    /** Create output format for writing */
    OutputFormat<T> createOutputFormat(Path path);
    
    /** Get supported format options */
    Set<String> getSupportedOptions();
}

/** Committer for file system operations */
class FileSystemCommitter implements Serializable {
    FileSystemCommitter(
        FileSystemFactory fsFactory,
        TableMetaStoreFactory msFactory,
        boolean overwrite,
        Path tmpPath,
        int parallelism,
        List<PartitionCommitPolicy> policies
    );
    
    /** Commit pending files */
    void commitPartitions(List<PartitionCommitInfo> partitionCommitInfos) throws Exception;
    
    /** Get commit policies */
    List<PartitionCommitPolicy> getCommitPolicies();
}

/** Output format for file systems */
class FileSystemOutputFormat<T> extends RichOutputFormat<T> {
    FileSystemOutputFormat(
        OutputFormatFactory<T> formatFactory,
        PartitionComputer<T> computer,
        Path outputPath,
        String filePrefix,
        boolean overwrite
    );
}

/** Bulk format with limit support */
class LimitableBulkFormat<T> implements BulkFormat<T> {
    LimitableBulkFormat(BulkFormat<T> format, long limit);
    
    /** Create reader with limit */
    Reader<T> createReader(Configuration config, FileSourceSplit split) throws IOException;
}

/** Manage temporary partition files */
class PartitionTempFileManager {
    PartitionTempFileManager(
        FileSystemFactory fsFactory,
        Path tmpPath,
        int taskNumber,
        String prefix
    );
    
    /** Create temporary file for partition */
    Path createPartitionTempFile(String partition) throws IOException;
    
    /** List temporary files for partition */
    List<Path> listPartitionTempFiles(String partition) throws IOException;
}

/**
 * Load partition information
 * Discovers and loads partition metadata from storage
 */
interface PartitionLoader {
    /** Load all partitions */
    List<Partition> loadPartitions() throws Exception;
    
    /** Load specific partition */
    Partition loadPartition(Map<String, String> partitionSpec) throws Exception;
}

/**
 * Extract time from partitions
 * Enables time-based partition processing
 */
interface PartitionTimeExtractor extends Serializable {
    /** Extract timestamp from partition path */
    LocalDateTime extract(List<String> partitionKeys, List<String> partitionValues);
}

/**
 * Streaming file writer
 * Handles streaming writes with proper watermark and checkpoint integration
 */
class StreamingFileWriter<IN> extends AbstractStreamOperator<PartitionCommitInfo>
    implements OneInputStreamOperator<IN, PartitionCommitInfo> {
    
    StreamingFileWriter(
        long bucketCheckInterval,
        PartitionComputer<IN> computer,
        PartitionWriterFactory<IN> writerFactory,
        FileSystemCommitter committer
    );
    
    /** Process streaming input element */
    void processElement(StreamRecord<IN> element) throws Exception;
}

/** Streaming sink implementation */
class StreamingSink<IN> implements Sink<IN> {
    StreamingSink(
        PartitionComputer<IN> computer,
        PartitionWriterFactory<IN> writerFactory,
        FileSystemCommitter committer,
        long bucketCheckInterval
    );
    
    /** Create sink writer */
    SinkWriter<IN> createWriter(InitContext context) throws IOException;
}

/** Operator for committing partitions in streaming mode */
class PartitionCommitter extends AbstractStreamOperator<Void>
    implements OneInputStreamOperator<PartitionCommitInfo, Void> {
    
    PartitionCommitter(List<PartitionCommitPolicy> policies);
    
    /** Process partition commit info */
    void processElement(StreamRecord<PartitionCommitInfo> element) throws Exception;
}

/**
 * Trigger for partition commits
 * Determines when partitions should be committed based on various criteria
 */
interface PartitionCommitTrigger extends Serializable {
    /** Check if partition should be committed */
    boolean shouldCommit(Context context) throws Exception;
    
    /** Trigger context interface */
    interface Context {
        /** Get current processing time */
        long currentProcessingTime();
        
        /** Get current watermark */
        long currentWatermark();
        
        /** Get partition create time */
        long partitionCreateTime();
    }
}

/** Processing time-based commit trigger */
class ProcTimeCommitTrigger implements PartitionCommitTrigger {
    ProcTimeCommitTrigger(long delay);
}

/**
 * Operator for file compaction
 * Handles merging of small files into larger ones for better performance
 */
class CompactOperator<T> extends AbstractStreamOperator<CompactResult>
    implements OneInputStreamOperator<T, CompactResult> {
    
    CompactOperator(
        CompactReader<T> reader,
        CompactWriter<T> writer,
        long targetFileSize,
        long compactionInterval
    );
}

/** Coordinator for compaction operations */
class CompactCoordinator extends AbstractStreamOperator<CompactionUnit>
    implements OneInputStreamOperator<PartitionCommitInfo, CompactionUnit> {
    
    CompactCoordinator(long targetFileSize, int maxConcurrentCompactions);
    
    /** Process partition commit information for compaction */
    void processElement(StreamRecord<PartitionCommitInfo> element) throws Exception;
}

/**
 * Interface for compact read operations
 * Reads data from files targeted for compaction
 */
interface CompactReader<T> extends Serializable {
    /** Read data from compaction source */
    Iterator<T> read(CompactionUnit unit) throws Exception;
}

/**
 * Interface for compact write operations
 * Writes compacted data to optimized file layouts
 */
interface CompactWriter<T> extends Serializable {
    /** Write compacted data */
    void write(Iterator<T> data, CompactionUnit unit) throws Exception;
}

/** File writer for compaction operations */
class CompactFileWriter<T> implements CompactWriter<T> {
    CompactFileWriter(OutputFormatFactory<T> formatFactory);
}

/**
 * Factory for metastore integration
 * Enables metadata management and catalog operations
 */
interface TableMetaStoreFactory extends Serializable {
    /** Create table metastore instance */
    TableMetaStore createTableMetaStore() throws Exception;
    
    /** Get metastore configuration */
    Map<String, String> getMetaStoreConfig();
}

// Create file system table factory
FileSystemTableFactory factory = new FileSystemTableFactory();

// Configure table properties
Map<String, String> properties = new HashMap<>();
properties.put("connector", "filesystem");
properties.put("path", "/data/my-table");
properties.put("format", "parquet");

// Create table source
Context sourceContext = new TestContext(properties, schema);
DynamicTableSource source = factory.createDynamicTableSource(sourceContext);

// Create table sink
Context sinkContext = new TestContext(properties, schema);
DynamicTableSink sink = factory.createDynamicTableSink(sinkContext);

// Set up partition writer
PartitionComputer<RowData> computer = new RowDataPartitionComputer(
    "__DEFAULT_PARTITION__",
    new String[]{"year", "month"},
    new LogicalType[]{DataTypes.INT().getLogicalType(), DataTypes.INT().getLogicalType()},
    fieldNames,
    fieldTypes
);

// Create streaming file writer
StreamingFileWriter<RowData> streamingWriter = new StreamingFileWriter<>(
    60000L, // bucket check interval
    computer,
    writerFactory,
    committer
);