Class Hardwood

java.lang.Object

dev.hardwood.Hardwood

All Implemented Interfaces:

AutoCloseable

public class Hardwood
extends Object
implements AutoCloseable

Entry point for reading Parquet files with a shared thread pool.

Use this when reading multiple files to share the executor across readers:

try (Hardwood hardwood = Hardwood.create()) {
    ParquetFileReader file1 = hardwood.open(path1);
    ParquetFileReader file2 = hardwood.open(path2);
    // ...
}

For single-file usage, ParquetFileReader.open(Path) is simpler.

Method Summary

Modifier and Type	Method	Description
void	close()
static Hardwood	create()	Create a new Hardwood instance with a thread pool sized to available processors.
static Hardwood	create(int threads)	Create a new Hardwood instance with a thread pool of the specified size.
ParquetFileReader	open(Path path)	Open a Parquet file for reading.
MultiFileParquetReader	openAll(Path first, Path... furtherPaths)	Open multiple Parquet files for reading with cross-file prefetching.
MultiFileParquetReader	openAll(List<Path> paths)	Open multiple Parquet files for reading with cross-file prefetching.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

create

public static Hardwood create()

Create a new Hardwood instance with a thread pool sized to available processors.

create

public static Hardwood create(int threads)

Create a new Hardwood instance with a thread pool of the specified size.

open

public ParquetFileReader open(Path path)
                       throws IOException

Open a Parquet file for reading.

Throws:

IOException

openAll

public MultiFileParquetReader openAll(List<Path> paths)
                               throws IOException

Open multiple Parquet files for reading with cross-file prefetching.

Returns a MultiFileParquetReader that reads the schema from the first file and provides factory methods for row-oriented (MultiFileParquetReader.createRowReader(ColumnProjection)) or column-oriented (MultiFileParquetReader.createColumnReaders(ColumnProjection)) access.

Parameters:

paths - the Parquet files to read (must not be empty)

Returns:

a MultiFileParquetReader for the given files

Throws:

IOException - if the first file cannot be opened or read

IllegalArgumentException - if the paths list is empty

openAll

public MultiFileParquetReader openAll(Path first,
 Path... furtherPaths)
                               throws IOException

Open multiple Parquet files for reading with cross-file prefetching.

Parameters:

first - the first Parquet file to read

furtherPaths - additional Parquet files to read

Returns:

a MultiFileParquetReader for the given files

Throws:

IOException - if the first file cannot be opened or read

close

public void close()

Specified by:

close in interface AutoCloseable