Class ParquetFileReader

java.lang.Object

dev.hardwood.reader.ParquetFileReader

All Implemented Interfaces:

AutoCloseable

public class ParquetFileReader
extends Object
implements AutoCloseable

Reader for individual Parquet files.

For single-file usage:

try (ParquetFileReader reader = ParquetFileReader.open(path)) {
    RowReader rows = reader.createRowReader();
    // ...
}

For multi-file usage with shared thread pool, use Hardwood.

Method Summary

Modifier and Type	Method	Description
void	close()
ColumnReader	createColumnReader(int columnIndex)	Create a ColumnReader for a column by index, spanning all row groups.
ColumnReader	createColumnReader(String columnName)	Create a ColumnReader for a named column, spanning all row groups.
RowReader	createRowReader()	Create a RowReader that iterates over all rows in all row groups.
RowReader	createRowReader(ColumnProjection projection)	Create a RowReader that iterates over selected columns in all row groups.
FileMetaData	getFileMetaData()
FileSchema	getFileSchema()
static ParquetFileReader	open(Path path)	Open a Parquet file with a dedicated context.
static ParquetFileReader	open(Path path, HardwoodContext context)	Open a Parquet file with a shared context.

Methods inherited from class Object

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

Method Details

open

public static ParquetFileReader open(Path path)
                              throws IOException

Open a Parquet file with a dedicated context. The context is closed when this reader is closed.

Throws:

IOException

open

public static ParquetFileReader open(Path path,
 HardwoodContext context)
                              throws IOException

Open a Parquet file with a shared context. The context is NOT closed when this reader is closed.

Throws:

IOException

getFileMetaData

public FileMetaData getFileMetaData()

getFileSchema

public FileSchema getFileSchema()

createColumnReader

public ColumnReader createColumnReader(String columnName)

Create a ColumnReader for a named column, spanning all row groups.

createColumnReader

public ColumnReader createColumnReader(int columnIndex)

Create a ColumnReader for a column by index, spanning all row groups.

createRowReader

public RowReader createRowReader()

Create a RowReader that iterates over all rows in all row groups.

createRowReader

public RowReader createRowReader(ColumnProjection projection)

Create a RowReader that iterates over selected columns in all row groups.

Parameters:

projection - specifies which columns to read

Returns:

a RowReader for the selected columns

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Throws:

IOException