Package org.apache.lucene.store

Class ByteBuffersDataInput

java.lang.Object

org.apache.lucene.store.DataInput

org.apache.lucene.store.ByteBuffersDataInput

All Implemented Interfaces:

Cloneable, RandomAccessInput, Accountable

public final class ByteBuffersDataInput
extends DataInput
implements Accountable, RandomAccessInput

A DataInput implementing RandomAccessInput and reading data from a list of ByteBuffers.

Field Summary

Fields

Modifier and Type	Field	Description
private final int	blockBits
private final int	blockMask
private final ByteBuffer[]	blocks
private final long	offset
private long	pos
private final long	size

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
ByteBuffersDataInput(List<ByteBuffer> buffers)	Read data from a set of contiguous buffers.

Method Summary

Modifier and Type	Method	Description
private final int	blockIndex(long pos)
private final int	blockOffset(long pos)
private int	blockSize()
(package private) static int	determineBlockPage(List<ByteBuffer> buffers)
private static void	ensureAssumptions(List<ByteBuffer> buffers)
private static final boolean	isPowerOfTwo(int v)
long	position()
long	ramBytesUsed()	Return the memory usage of this object in bytes.
byte	readByte()	Reads and returns a single byte.
byte	readByte(long pos)	Reads a byte at the given position in the file
void	readBytes(byte[] arr, int off, int len)	Reads a specified number of bytes into an array at the specified offset.
void	readBytes(ByteBuffer buffer, int len)	Reads exactly len bytes into the given buffer.
int	readInt(long pos)	Reads an integer at the given position in the file
long	readLong(long pos)	Reads a long at the given position in the file
short	readShort(long pos)	Reads a short at the given position in the file
void	seek(long position)
long	size()
ByteBuffersDataInput	slice(long offset, long length)
private static List<ByteBuffer>	sliceBufferList(List<ByteBuffer> buffers, long offset, long length)
String	toString()

Methods inherited from class org.apache.lucene.store.DataInput

clone, readBytes, readInt, readLELongs, readLong, readMapOfStrings, readSetOfStrings, readShort, readString, readVInt, readVLong, readZInt, readZLong, skipBytes

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Field Details

blocks

private final ByteBuffer[] blocks

blockBits

private final int blockBits

blockMask

private final int blockMask

size

private final long size

offset

private final long offset

pos

private long pos

Constructor Details

ByteBuffersDataInput

public ByteBuffersDataInput(List<ByteBuffer> buffers)

Read data from a set of contiguous buffers. All data buffers except for the last one must have an identical remaining number of bytes in the buffer (that is a power of two). The last buffer can be of an arbitrary remaining length.

Method Details

size

public long size()

ramBytesUsed

public long ramBytesUsed()

Description copied from interface: Accountable

Return the memory usage of this object in bytes. Negative values are illegal.

Specified by:

ramBytesUsed in interface Accountable

readByte

public byte readByte()
              throws EOFException

Description copied from class: DataInput

Reads and returns a single byte.

Specified by:

readByte in class DataInput

Throws:

EOFException

See Also:

• DataOutput.writeByte(byte)

readBytes

public void readBytes(ByteBuffer buffer,
 int len)
               throws EOFException

Reads exactly len bytes into the given buffer. The buffer must have enough remaining limit. If there are fewer than len bytes in the input, EOFException is thrown.

Throws:

EOFException

readBytes

public void readBytes(byte[] arr,
 int off,
 int len)
               throws EOFException

Description copied from class: DataInput

Reads a specified number of bytes into an array at the specified offset.

Specified by:

readBytes in class DataInput

Parameters:

arr - the array to read bytes into

off - the offset in the array to start storing bytes

len - the number of bytes to read

Throws:

EOFException

See Also:

• DataOutput.writeBytes(byte[],int)

readByte

public byte readByte(long pos)

Description copied from interface: RandomAccessInput

Reads a byte at the given position in the file

Specified by:

readByte in interface RandomAccessInput

See Also:

• DataInput.readByte()

readShort

public short readShort(long pos)

Description copied from interface: RandomAccessInput

Reads a short at the given position in the file

Specified by:

readShort in interface RandomAccessInput

See Also:

• DataInput.readShort()

readInt

public int readInt(long pos)

Description copied from interface: RandomAccessInput

Reads an integer at the given position in the file

Specified by:

readInt in interface RandomAccessInput

See Also:

• DataInput.readInt()

readLong

public long readLong(long pos)

Description copied from interface: RandomAccessInput

Reads a long at the given position in the file

Specified by:

readLong in interface RandomAccessInput

See Also:

• DataInput.readLong()

position

public long position()

seek

public void seek(long position)
          throws EOFException

Throws:

EOFException

slice

public ByteBuffersDataInput slice(long offset,
 long length)

toString

public String toString()

Overrides:

toString in class Object

blockIndex

private final int blockIndex(long pos)

blockOffset

private final int blockOffset(long pos)

blockSize

private int blockSize()

isPowerOfTwo

private static final boolean isPowerOfTwo(int v)

ensureAssumptions

private static void ensureAssumptions(List<ByteBuffer> buffers)

determineBlockPage

static int determineBlockPage(List<ByteBuffer> buffers)

sliceBufferList

private static List<ByteBuffer> sliceBufferList(List<ByteBuffer> buffers,
 long offset,
 long length)