org.apache.hadoop.io.compress.snappy

类 SnappyCompressor

java.lang.Object

org.apache.hadoop.io.compress.snappy.SnappyCompressor

所有已实现的接口:

Compressor

public class SnappyCompressor
extends Object
implements Compressor

A Compressor based on the snappy compression algorithm. http://code.google.com/p/snappy/

构造器概要

构造器

构造器和说明
SnappyCompressor() Creates a new compressor with the default buffer size.
SnappyCompressor(int directBufferSize) Creates a new compressor.

方法概要

方法

限定符和类型	方法和说明
int	compress(byte[] b, int off, int len) Fills specified buffer with compressed data.
void	end() Closes the compressor and discards any unprocessed input.
void	finish() When called, indicates that compression should end with the current contents of the input buffer.
boolean	finished() Returns true if the end of the compressed data output stream has been reached.
long	getBytesRead() Return number of bytes given to this compressor since last reset.
long	getBytesWritten() Return number of bytes consumed by callers of compress since last reset.
boolean	needsInput() Returns true if the input data buffer is empty and #setInput() should be called to provide more input.
void	reinit(Configuration conf) Prepare the compressor to be used in a new stream with settings defined in the given Configuration
void	reset() Resets compressor so that a new set of input data can be processed.
void	setDictionary(byte[] b, int off, int len) Does nothing.
void	setInput(byte[] b, int off, int len) Sets input data for compression.

从类继承的方法 java.lang.Object

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

构造器详细资料

SnappyCompressor

public SnappyCompressor(int directBufferSize)

Creates a new compressor.

参数:

directBufferSize - size of the direct buffer to be used.

SnappyCompressor

public SnappyCompressor()

Creates a new compressor with the default buffer size.

方法详细资料

setInput

public void setInput(byte[] b,
            int off,
            int len)

Sets input data for compression. This should be called whenever #needsInput() returns true indicating that more input data is required.

指定者:

setInput 在接口中 Compressor

参数:

b - Input data

off - Start offset

len - Length

setDictionary

public void setDictionary(byte[] b,
                 int off,
                 int len)

Does nothing.

指定者:

setDictionary 在接口中 Compressor

参数:

b - Dictionary data bytes

off - Start offset

len - Length

needsInput

public boolean needsInput()

Returns true if the input data buffer is empty and #setInput() should be called to provide more input.

指定者:

needsInput 在接口中 Compressor

返回:

true if the input data buffer is empty and #setInput() should be called in order to provide more input.

finish

public void finish()

When called, indicates that compression should end with the current contents of the input buffer.

指定者:

finish 在接口中 Compressor

finished

public boolean finished()

Returns true if the end of the compressed data output stream has been reached.

指定者:

finished 在接口中 Compressor

返回:

true if the end of the compressed data output stream has been reached.

compress

public int compress(byte[] b,
           int off,
           int len)
             throws IOException

Fills specified buffer with compressed data. Returns actual number of bytes of compressed data. A return value of 0 indicates that needsInput() should be called in order to determine if more input data is required.

指定者:

compress 在接口中 Compressor

参数:

b - Buffer for the compressed data

off - Start offset of the data

len - Size of the buffer

返回:

The actual number of bytes of compressed data.

抛出:

IOException

reset

public void reset()

Resets compressor so that a new set of input data can be processed.

指定者:

reset 在接口中 Compressor

reinit

public void reinit(Configuration conf)

Prepare the compressor to be used in a new stream with settings defined in the given Configuration

指定者:

reinit 在接口中 Compressor

参数:

conf - Configuration from which new setting are fetched

getBytesRead

public long getBytesRead()

Return number of bytes given to this compressor since last reset.

指定者:

getBytesRead 在接口中 Compressor

getBytesWritten

public long getBytesWritten()

Return number of bytes consumed by callers of compress since last reset.

指定者:

getBytesWritten 在接口中 Compressor

end

public void end()

Closes the compressor and discards any unprocessed input.

指定者:

end 在接口中 Compressor