org.apache.lucene.store

Class ByteBufferIndexInput

java.lang.Object

org.apache.lucene.store.DataInput

org.apache.lucene.store.IndexInput

org.apache.lucene.store.ByteBufferIndexInput

All Implemented Interfaces:

Closeable, AutoCloseable, Cloneable, RandomAccessInput

public abstract class ByteBufferIndexInput
extends IndexInput
implements RandomAccessInput

Base IndexInput implementation that uses an array of ByteBuffers to represent a file.

Because Java's ByteBuffer uses an int to address the values, it's necessary to access a file greater Integer.MAX_VALUE in size using multiple byte buffers.

For efficiency, this class requires that the buffers are a power-of-two (chunkSizePower).

Field Summary

Fields

Modifier and Type	Field and Description
protected ByteBuffer[]	buffers
protected long	chunkSizeMask
protected int	chunkSizePower
protected ByteBuffer	curBuf
protected int	curBufIndex
protected org.apache.lucene.store.ByteBufferGuard	guard
protected boolean	isClone
protected long	length

Method Summary

Modifier and Type	Method and Description
protected ByteBufferIndexInput	buildSlice(String sliceDescription, long offset, long length) Builds the actual sliced IndexInput (may apply extra offset in subclasses).
ByteBufferIndexInput	clone() Returns a clone of this stream.
void	close() Closes the stream to further operations.
long	getFilePointer() Returns the current position in this file, where the next read will occur.
long	length() The number of bytes in the file.
protected ByteBufferIndexInput	newCloneInstance(String newResourceDescription, ByteBuffer[] newBuffers, int offset, long length) Factory method that creates a suitable implementation of this class for the given ByteBuffers.
static ByteBufferIndexInput	newInstance(String resourceDescription, ByteBuffer[] buffers, long length, int chunkSizePower, org.apache.lucene.store.ByteBufferGuard guard)
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[] b, int offset, int len) Reads a specified number of bytes into an array at the specified offset.
int	readInt() Reads four bytes and returns an int.
int	readInt(long pos) Reads an integer at the given position in the file
long	readLong() Reads eight bytes and returns a long.
long	readLong(long pos) Reads a long at the given position in the file
short	readShort() Reads two bytes and returns a short.
short	readShort(long pos) Reads a short at the given position in the file
void	seek(long pos) Sets current position in this file, where the next read will occur.
ByteBufferIndexInput	slice(String sliceDescription, long offset, long length) Creates a slice of this index input, with the given description, offset, and length.

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

getFullSliceDescription, randomAccessSlice, toString

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

readBytes, readMapOfStrings, readSetOfStrings, readString, readVInt, readVLong, readZInt, readZLong, skipBytes

Methods inherited from class java.lang.Object

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

Field Detail

length

protected final long length

chunkSizeMask

protected final long chunkSizeMask

chunkSizePower

protected final int chunkSizePower

guard

protected final org.apache.lucene.store.ByteBufferGuard guard

buffers

protected ByteBuffer[] buffers

curBufIndex

protected int curBufIndex

curBuf

protected ByteBuffer curBuf

isClone

protected boolean isClone

Method Detail

newInstance

public static ByteBufferIndexInput newInstance(String resourceDescription,
                                               ByteBuffer[] buffers,
                                               long length,
                                               int chunkSizePower,
                                               org.apache.lucene.store.ByteBufferGuard guard)

readByte

public final byte readByte()
                    throws IOException

Description copied from class: DataInput

Reads and returns a single byte.

Specified by:

readByte in class DataInput

Throws:

IOException

See Also:

DataOutput.writeByte(byte)

readBytes

public final void readBytes(byte[] b,
                            int offset,
                            int len)
                     throws IOException

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:

b - the array to read bytes into

offset - the offset in the array to start storing bytes

len - the number of bytes to read

Throws:

IOException

See Also:

DataOutput.writeBytes(byte[],int)

readShort

public final short readShort()
                      throws IOException

Description copied from class: DataInput

Reads two bytes and returns a short.

Overrides:

readShort in class DataInput

Throws:

IOException

See Also:

DataOutput.writeByte(byte)

readInt

public final int readInt()
                  throws IOException

Description copied from class: DataInput

Reads four bytes and returns an int.

Overrides:

readInt in class DataInput

Throws:

IOException

See Also:

DataOutput.writeInt(int)

readLong

public final long readLong()
                    throws IOException

Description copied from class: DataInput

Reads eight bytes and returns a long.

Overrides:

readLong in class DataInput

Throws:

IOException

See Also:

DataOutput.writeLong(long)

getFilePointer

public long getFilePointer()

Description copied from class: IndexInput

Returns the current position in this file, where the next read will occur.

Specified by:

getFilePointer in class IndexInput

See Also:

IndexInput.seek(long)

seek

public void seek(long pos)
          throws IOException

Description copied from class: IndexInput

Sets current position in this file, where the next read will occur. If this is beyond the end of the file then this will throw EOFException and then the stream is in an undetermined state.

Specified by:

seek in class IndexInput

Throws:

IOException

See Also:

IndexInput.getFilePointer()

readByte

public byte readByte(long pos)
              throws IOException

Description copied from interface: RandomAccessInput

Reads a byte at the given position in the file

Specified by:

readByte in interface RandomAccessInput

Throws:

IOException

See Also:

DataInput.readByte()

readShort

public short readShort(long pos)
                throws IOException

Description copied from interface: RandomAccessInput

Reads a short at the given position in the file

Specified by:

readShort in interface RandomAccessInput

Throws:

IOException

See Also:

DataInput.readShort()

readInt

public int readInt(long pos)
            throws IOException

Description copied from interface: RandomAccessInput

Reads an integer at the given position in the file

Specified by:

readInt in interface RandomAccessInput

Throws:

IOException

See Also:

DataInput.readInt()

readLong

public long readLong(long pos)
              throws IOException

Description copied from interface: RandomAccessInput

Reads a long at the given position in the file

Specified by:

readLong in interface RandomAccessInput

Throws:

IOException

See Also:

DataInput.readLong()

length

public final long length()

Description copied from class: IndexInput

The number of bytes in the file.

Specified by:

length in class IndexInput

clone

public final ByteBufferIndexInput clone()

Description copied from class: IndexInput

Returns a clone of this stream.

Clones of a stream access the same data, and are positioned at the same point as the stream they were cloned from.

Expert: Subclasses must ensure that clones may be positioned at different points in the input from each other and from the stream they were cloned from.

Warning: Lucene never closes cloned IndexInputs, it will only call IndexInput.close() on the original object.

If you access the cloned IndexInput after closing the original object, any readXXX methods will throw AlreadyClosedException.

This method is NOT thread safe, so if the current IndexInput is being used by one thread while clone is called by another, disaster could strike.

Overrides:

clone in class IndexInput

slice

public final ByteBufferIndexInput slice(String sliceDescription,
                                        long offset,
                                        long length)

Creates a slice of this index input, with the given description, offset, and length. The slice is seeked to the beginning.

Specified by:

slice in class IndexInput

buildSlice

protected ByteBufferIndexInput buildSlice(String sliceDescription,
                                          long offset,
                                          long length)

Builds the actual sliced IndexInput (may apply extra offset in subclasses).

newCloneInstance

protected ByteBufferIndexInput newCloneInstance(String newResourceDescription,
                                                ByteBuffer[] newBuffers,
                                                int offset,
                                                long length)

Factory method that creates a suitable implementation of this class for the given ByteBuffers.

close

public final void close()
                 throws IOException

Description copied from class: IndexInput

Closes the stream to further operations.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in class IndexInput

Throws:

IOException