org.apache.parquet.io

Class SeekableInputStream

java.lang.Object

java.io.InputStream

org.apache.parquet.io.SeekableInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

DelegatingSeekableInputStream

public abstract class SeekableInputStream
extends InputStream

SeekableInputStream is an interface with the methods needed by Parquet to read data from a file or Hadoop data stream.

Constructor Summary

Constructors

Constructor and Description
SeekableInputStream()

Method Summary

Modifier and Type	Method and Description
abstract long	getPos() Return the current position in the InputStream.
abstract int	read(ByteBuffer buf) Read buf.remaining() bytes of data into a ByteBuffer.
abstract void	readFully(byte[] bytes) Read a byte array of data, from position 0 to the end of the array.
abstract void	readFully(byte[] bytes, int start, int len) Read len bytes of data into an array, at position start.
abstract void	readFully(ByteBuffer buf) Read buf.remaining() bytes of data into a ByteBuffer.
void	readVectored(List<ParquetFileRange> ranges, ByteBufferAllocator allocator) Read a set of disjoint file ranges in a vectored manner.
boolean	readVectoredAvailable(ByteBufferAllocator allocator) Is the readVectored(List, ByteBufferAllocator) method available?
abstract void	seek(long newPos) Seek to a new position in the InputStream.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

SeekableInputStream

public SeekableInputStream()

Method Detail

getPos

public abstract long getPos()
                     throws IOException

Return the current position in the InputStream.

Returns:

current position in bytes from the start of the stream

Throws:

IOException - If the underlying stream throws IOException

seek

public abstract void seek(long newPos)
                   throws IOException

Seek to a new position in the InputStream.

Parameters:

newPos - the new position to seek to

Throws:

IOException - If the underlying stream throws IOException

readFully

public abstract void readFully(byte[] bytes)
                        throws IOException

Read a byte array of data, from position 0 to the end of the array.

This method is equivalent to read(bytes, 0, bytes.length).

This method will block until len bytes are available to copy into the array, or will throw EOFException if the stream ends before the array is full.

Parameters:

bytes - a byte array to fill with data from the stream

Throws:

IOException - If the underlying stream throws IOException

EOFException - If the stream has fewer bytes left than are needed to fill the array, bytes.length

readFully

public abstract void readFully(byte[] bytes,
                               int start,
                               int len)
                        throws IOException

Read len bytes of data into an array, at position start.

This method will block until len bytes are available to copy into the array, or will throw EOFException if the stream ends before the array is full.

Parameters:

bytes - a byte array to fill with data from the stream

start - the starting position in the byte array for data

len - the length of bytes to read into the byte array

Throws:

IOException - If the underlying stream throws IOException

EOFException - If the stream has fewer than len bytes left

read

public abstract int read(ByteBuffer buf)
                  throws IOException

Read buf.remaining() bytes of data into a ByteBuffer.

This method will copy available bytes into the buffer, reading at most buf.remaining() bytes. The number of bytes actually copied is returned by the method, or -1 is returned to signal that the end of the underlying stream has been reached.

Parameters:

buf - a byte buffer to fill with data from the stream

Returns:

the number of bytes read or -1 if the stream ended

Throws:

IOException - If the underlying stream throws IOException

readFully

public abstract void readFully(ByteBuffer buf)
                        throws IOException

Read buf.remaining() bytes of data into a ByteBuffer.

This method will block until buf.remaining() bytes are available to copy into the buffer, or will throw EOFException if the stream ends before the buffer is full.

Parameters:

buf - a byte buffer to fill with data from the stream

Throws:

IOException - If the underlying stream throws IOException

EOFException - If the stream has fewer bytes left than are needed to fill the buffer, buf.remaining()

readVectored

public void readVectored(List<ParquetFileRange> ranges,
                         ByteBufferAllocator allocator)
                  throws IOException

Read a set of disjoint file ranges in a vectored manner.

Parameters:

ranges - a list of non-overlapping file ranges to read

allocator - the allocator to use for allocating ByteBuffers

Throws:

UnsupportedOperationException - if not available in this class/runtime (default)

EOFException - if a range is past the known end of the file.

IOException - any IO problem initiating the read operations.

IllegalArgumentException - if there are overlapping ranges or a range element is invalid

readVectoredAvailable

public boolean readVectoredAvailable(ByteBufferAllocator allocator)

Is the readVectored(List, ByteBufferAllocator) method available?

Parameters:

allocator - the allocator to use for allocating ByteBuffers

Returns:

True if the operation is considered available for this allocator in the hadoop runtime.