DiffKeyDeltaEncoder (Apache HBase 1.1.7 API)

java.lang.Object
- org.apache.hadoop.hbase.io.encoding.DiffKeyDeltaEncoder

All Implemented Interfaces:

DataBlockEncoder
```
@InterfaceAudience.Private
public class DiffKeyDeltaEncoder
extends Object
```
Compress using: - store size of common prefix - save column family once, it is same within HFile - use integer compression for key, value and prefix (7-bit encoding) - use bits to avoid duplication key length, value length and type if it same as previous - store in 3 bits length of timestamp field - allow diff in timestamp instead of actual value Format: - 1 byte: flag - 1-5 bytes: key length (only if FLAG_SAME_KEY_LENGTH is not set in flag) - 1-5 bytes: value length (only if FLAG_SAME_VALUE_LENGTH is not set in flag) - 1-5 bytes: prefix length - ... bytes: rest of the row (if prefix length is small enough) - ... bytes: qualifier (or suffix depending on prefix length) - 1-8 bytes: timestamp or diff - 1 byte: type (only if FLAG_SAME_TYPE is not set in the flag) - ... bytes: value

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`protected static class`	`BufferedDataBlockEncoder.BufferedEncodedSeeker<STATE extends BufferedDataBlockEncoder.SeekerState>`
`protected static class`	`BufferedDataBlockEncoder.ClonedSeekerState` Copies only the key part of the keybuffer by doing a deep copy and passes the seeker state members for taking a clone.
`protected static class`	`BufferedDataBlockEncoder.SeekerState`
`protected static class`	`DiffKeyDeltaEncoder.DiffCompressionState`
`protected static class`	`DiffKeyDeltaEncoder.DiffSeekerState`

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.io.encoding.DataBlockEncoder
DataBlockEncoder.EncodedSeeker

Constructor Summary

Constructors
Constructor and Description

DiffKeyDeltaEncoder()

Constructors
Constructor and Description
`DiffKeyDeltaEncoder()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`afterDecodingKeyValue(DataInputStream source, ByteBuffer dest, HFileBlockDefaultDecodingContext decodingCtx)`
`protected int`	`afterEncodingKeyValue(Cell cell, DataOutputStream out, HFileBlockDefaultEncodingContext encodingCtx)`
`DataBlockEncoder.EncodedSeeker`	`createSeeker(KeyValue.KVComparator comparator, HFileBlockDecodingContext decodingCtx)` Create a HFileBlock seeker which find KeyValues within a block.
`ByteBuffer`	`decodeKeyValues(DataInputStream source, HFileBlockDecodingContext blkDecodingCtx)` Decode.
`int`	`encode(Cell cell, HFileBlockEncodingContext encodingCtx, DataOutputStream out)` Encodes a KeyValue.
`void`	`endBlockEncoding(HFileBlockEncodingContext encodingCtx, DataOutputStream out, byte[] uncompressedBytesWithHeader)` Ends encoding for a block of KeyValues.
`protected static void`	`ensureSpace(ByteBuffer out, int length)` Asserts that there is at least the given amount of unfilled space remaining in the given buffer.
`ByteBuffer`	`getFirstKeyInBlock(ByteBuffer block)` Return first key in block.
`protected ByteBuffer`	`internalDecodeKeyValues(DataInputStream source, int allocateHeaderLength, int skipLastBytes, HFileBlockDefaultDecodingContext decodingCtx)`
`int`	`internalEncode(Cell cell, HFileBlockDefaultEncodingContext encodingContext, DataOutputStream out)`
`HFileBlockDecodingContext`	`newDataBlockDecodingContext(HFileContext meta)` Creates an encoder specific decoding context, which will prepare the data before actual decoding
`HFileBlockEncodingContext`	`newDataBlockEncodingContext(DataBlockEncoding encoding, byte[] header, HFileContext meta)` Creates a encoder specific encoding context
`void`	`startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx, DataOutputStream out)` Starts encoding for a block of KeyValues.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - DiffKeyDeltaEncoder
```
public DiffKeyDeltaEncoder()
```
- Method Detail
  - internalEncode
```
public int internalEncode(Cell cell,
                 HFileBlockDefaultEncodingContext encodingContext,
                 DataOutputStream out)
                   throws IOException
```
    Throws:
    
    IOException
  - getFirstKeyInBlock
```
public ByteBuffer getFirstKeyInBlock(ByteBuffer block)
```
    Description copied from interface: DataBlockEncoder
    
    Return first key in block. Useful for indexing. Typically does not make a deep copy but returns a buffer wrapping a segment of the actual block's byte array. This is because the first key in block is usually stored unencoded.
    
    Parameters:
    block - encoded block we want index, the position will not change
    
    Returns:
    First key in block.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - createSeeker
```
public DataBlockEncoder.EncodedSeeker createSeeker(KeyValue.KVComparator comparator,
                                          HFileBlockDecodingContext decodingCtx)
```
    Description copied from interface: DataBlockEncoder
    
    Create a HFileBlock seeker which find KeyValues within a block.
    
    Parameters:
    comparator - what kind of comparison should be used
    
    Returns:
    A newly created seeker.
  - internalDecodeKeyValues
```
protected ByteBuffer internalDecodeKeyValues(DataInputStream source,
                                 int allocateHeaderLength,
                                 int skipLastBytes,
                                 HFileBlockDefaultDecodingContext decodingCtx)
                                      throws IOException
```
    Throws:
    
    IOException
  - decodeKeyValues
```
public ByteBuffer decodeKeyValues(DataInputStream source,
                         HFileBlockDecodingContext blkDecodingCtx)
                           throws IOException
```
    Description copied from interface: DataBlockEncoder
    
    Decode.
    
    Specified by:
    
    decodeKeyValues in interface DataBlockEncoder
    
    Parameters:
    source - Compressed stream of KeyValues.
    
    Returns:
    Uncompressed block of KeyValues.
    
    Throws:
    
    IOException - If there is an error in source.
  - afterEncodingKeyValue
```
protected final int afterEncodingKeyValue(Cell cell,
                        DataOutputStream out,
                        HFileBlockDefaultEncodingContext encodingCtx)
                                   throws IOException
```
    Parameters:
    cell -
    out -
    encodingCtx -
    
    Returns:
    unencoded size added
    
    Throws:
    
    IOException
  - afterDecodingKeyValue
```
protected final void afterDecodingKeyValue(DataInputStream source,
                         ByteBuffer dest,
                         HFileBlockDefaultDecodingContext decodingCtx)
                                    throws IOException
```
    Throws:
    
    IOException
  - newDataBlockEncodingContext
```
public HFileBlockEncodingContext newDataBlockEncodingContext(DataBlockEncoding encoding,
                                                    byte[] header,
                                                    HFileContext meta)
```
    Description copied from interface: DataBlockEncoder
    
    Creates a encoder specific encoding context
    
    Specified by:
    
    newDataBlockEncodingContext in interface DataBlockEncoder
    
    Parameters:
    encoding - encoding strategy used
    header - header bytes to be written, put a dummy header here if the header is unknown
    meta - HFile meta data
    
    Returns:
    a newly created encoding context
  - newDataBlockDecodingContext
```
public HFileBlockDecodingContext newDataBlockDecodingContext(HFileContext meta)
```
    Description copied from interface: DataBlockEncoder
    
    Creates an encoder specific decoding context, which will prepare the data before actual decoding
    
    Specified by:
    
    newDataBlockDecodingContext in interface DataBlockEncoder
    
    Parameters:
    meta - HFile meta data
    
    Returns:
    a newly created decoding context
  - ensureSpace
```
protected static void ensureSpace(ByteBuffer out,
               int length)
                           throws EncoderBufferTooSmallException
```
    Asserts that there is at least the given amount of unfilled space remaining in the given buffer.
    
    Parameters:
    out - typically, the buffer we are writing to
    length - the required space in the buffer
    
    Throws:
    
    EncoderBufferTooSmallException - If there are no enough bytes.
  - startBlockEncoding
```
public void startBlockEncoding(HFileBlockEncodingContext blkEncodingCtx,
                      DataOutputStream out)
                        throws IOException
```
    Description copied from interface: DataBlockEncoder
    
    Starts encoding for a block of KeyValues. Call DataBlockEncoder.endBlockEncoding(HFileBlockEncodingContext, DataOutputStream, byte[]) to finish encoding of a block.
    
    Specified by:
    
    startBlockEncoding in interface DataBlockEncoder
    
    Throws:
    
    IOException
  - encode
```
public int encode(Cell cell,
         HFileBlockEncodingContext encodingCtx,
         DataOutputStream out)
           throws IOException
```
    Description copied from interface: DataBlockEncoder
    
    Encodes a KeyValue.
    
    Specified by:
    
    encode in interface DataBlockEncoder
    
    Returns:
    unencoded kv size written
    
    Throws:
    
    IOException
  - endBlockEncoding
```
public void endBlockEncoding(HFileBlockEncodingContext encodingCtx,
                    DataOutputStream out,
                    byte[] uncompressedBytesWithHeader)
                      throws IOException
```
    Description copied from interface: DataBlockEncoder
    
    Ends encoding for a block of KeyValues. Gives a chance for the encoder to do the finishing stuff for the encoded block. It must be called at the end of block encoding.
    
    Specified by:
    
    endBlockEncoding in interface DataBlockEncoder
    
    Throws:
    
    IOException

Class DiffKeyDeltaEncoder

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.hbase.io.encoding.DataBlockEncoder

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

DiffKeyDeltaEncoder

Method Detail

internalEncode

getFirstKeyInBlock

toString

createSeeker

internalDecodeKeyValues

decodeKeyValues

afterEncodingKeyValue

afterDecodingKeyValue

newDataBlockEncodingContext

newDataBlockDecodingContext

ensureSpace

startBlockEncoding

encode

endBlockEncoding