org.apache.lucene.store
Class BufferedIndexInput

java.lang.Object
  org.apache.lucene.store.IndexInput
      org.apache.lucene.store.BufferedIndexInput

All Implemented Interfaces:

Closeable, Cloneable

Direct Known Subclasses:

SimpleFSDirectory.SimpleFSIndexInput

public abstract class BufferedIndexInput
extends IndexInput

Base implementation class for buffered IndexInput.

Field Summary

protected byte[]	buffer
static int	BUFFER_SIZE Default buffer size

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

copyBuf

Constructor Summary

BufferedIndexInput()

BufferedIndexInput(int bufferSize)
Inits BufferedIndexInput with a specific bufferSize

Method Summary

Object	clone() Returns a clone of this stream.
void	copyBytes(IndexOutput out, long numBytes) Copies numBytes bytes to the given IndexOutput.
protected int	flushBuffer(IndexOutput out, long numBytes) Flushes the in-memory bufer to the given output, copying at most numBytes.
int	getBufferSize() Returns buffer size.
long	getFilePointer() Returns the current position in this file, where the next read will occur.
protected void	newBuffer(byte[] newBuffer)
byte	readByte() Reads and returns a single byte.
void	readBytes(byte[] b, int offset, int len) Reads a specified number of bytes into an array at the specified offset.
void	readBytes(byte[] b, int offset, int len, boolean useBuffer) Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer).
int	readInt() Reads four bytes and returns an int.
protected abstract void	readInternal(byte[] b, int offset, int length) Expert: implements buffer refill.
long	readLong() Reads eight bytes and returns a long.
int	readVInt() Reads an int stored in variable-length format.
long	readVLong() Reads a long stored in variable-length format.
void	seek(long pos) Sets current position in this file, where the next read will occur.
protected abstract void	seekInternal(long pos) Expert: implements seek.
void	setBufferSize(int newSize) Change the buffer size used by this IndexInput

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

close, length, readChars, readString, readStringStringMap, setModifiedUTF8StringsMode, skipChars

Methods inherited from class java.lang.Object

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

Field Detail

BUFFER_SIZE

public static final int BUFFER_SIZE

Default buffer size

See Also:

Constant Field Values

buffer

protected byte[] buffer

Constructor Detail

BufferedIndexInput

public BufferedIndexInput()

BufferedIndexInput

public BufferedIndexInput(int bufferSize)

Inits BufferedIndexInput with a specific bufferSize

Method Detail

readByte

public byte readByte()
              throws IOException

Description copied from class: IndexInput

Reads and returns a single byte.

Specified by:

readByte in class IndexInput

Throws:

IOException

See Also:

IndexOutput.writeByte(byte)

setBufferSize

public void setBufferSize(int newSize)

Change the buffer size used by this IndexInput

newBuffer

protected void newBuffer(byte[] newBuffer)

getBufferSize

public int getBufferSize()

Returns buffer size. @see #setBufferSize

readBytes

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

Description copied from class: IndexInput

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

Specified by:

readBytes in class IndexInput

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:

IndexOutput.writeBytes(byte[],int)

readBytes

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

Description copied from class: IndexInput

Reads a specified number of bytes into an array at the specified offset with control over whether the read should be buffered (callers who have their own buffer should pass in "false" for useBuffer). Currently only BufferedIndexInput respects this parameter.

Overrides:

readBytes in class IndexInput

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

useBuffer - set to false if the caller will handle buffering.

Throws:

IOException

See Also:

IndexOutput.writeBytes(byte[],int)

readInt

public int readInt()
            throws IOException

Description copied from class: IndexInput

Reads four bytes and returns an int.

Overrides:

readInt in class IndexInput

Throws:

IOException

See Also:

IndexOutput.writeInt(int)

readLong

public long readLong()
              throws IOException

Description copied from class: IndexInput

Reads eight bytes and returns a long.

Overrides:

readLong in class IndexInput

Throws:

IOException

See Also:

IndexOutput.writeLong(long)

readVInt

public int readVInt()
             throws IOException

Description copied from class: IndexInput

Reads an int stored in variable-length format. Reads between one and five bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Overrides:

readVInt in class IndexInput

Throws:

IOException

See Also:

IndexOutput.writeVInt(int)

readVLong

public long readVLong()
               throws IOException

Description copied from class: IndexInput

Reads a long stored in variable-length format. Reads between one and nine bytes. Smaller values take fewer bytes. Negative numbers are not supported.

Overrides:

readVLong in class IndexInput

Throws:

IOException

readInternal

protected abstract void readInternal(byte[] b,
                                     int offset,
                                     int length)
                              throws IOException

Expert: implements buffer refill. Reads bytes from the current position in the input.

Parameters:

b - the array to read bytes into

offset - the offset in the array to start storing bytes

length - the number of bytes to read

Throws:

IOException

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.

Specified by:

seek in class IndexInput

Throws:

IOException

See Also:

IndexInput.getFilePointer()

seekInternal

protected abstract void seekInternal(long pos)
                              throws IOException

Expert: implements seek. Sets current position in this file, where the next readInternal(byte[],int,int) will occur.

Throws:

IOException

See Also:

readInternal(byte[],int,int)

clone

public Object 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.

Overrides:

clone in class IndexInput

flushBuffer

protected int flushBuffer(IndexOutput out,
                          long numBytes)
                   throws IOException

Flushes the in-memory bufer to the given output, copying at most numBytes.

NOTE: this method does not refill the buffer, however it does advance the buffer position.

Returns:

the number of bytes actually flushed from the in-memory buffer.

Throws:

IOException

copyBytes

public void copyBytes(IndexOutput out,
                      long numBytes)
               throws IOException

Description copied from class: IndexInput

Copies numBytes bytes to the given IndexOutput.

NOTE: this method uses an intermediate buffer to copy the bytes. Consider overriding it in your implementation, if you can make a better, optimized copy.

NOTE ensure that there are enough bytes in the input to copy to output. Otherwise, different exceptions may be thrown, depending on the implementation.

Overrides:

copyBytes in class IndexInput

Throws:

IOException