ByteBuff (Apache HBase 2.1.0-cdh6.3.2 API)

java.lang.Object
- org.apache.hadoop.hbase.nio.ByteBuff

Direct Known Subclasses:

MultiByteBuff, SingleByteBuff
```
@InterfaceAudience.Private
public abstract class ByteBuff
extends Object
```
An abstract class that abstracts out as to how the byte buffers are used, either single or multiple. We have this interface because the java's ByteBuffers cannot be sub-classed. This class provides APIs similar to the ones provided in java's nio ByteBuffers and allows you to do positional reads/writes and relative reads and writes on the underlying BB. In addition to it, we have some additional APIs which helps us in the read path.

Constructor Summary

Constructors
Constructor and Description

ByteBuff()

Constructors
Constructor and Description
`ByteBuff()`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract byte[]`	`array()`
`abstract int`	`arrayOffset()`
`abstract ByteBuffer`	`asSubByteBuffer(int length)` Returns bytes from current position till length specified, as a single ByteBuffer.
`abstract void`	`asSubByteBuffer(int offset, int length, ObjectIntPair<ByteBuffer> pair)` Returns bytes from given offset till length specified, as a single ByteBuffer.
`abstract int`	`capacity()`
`static int`	`channelRead(ReadableByteChannel channel, ByteBuffer buf)`
`static int`	`compareTo(ByteBuff buf1, int o1, int len1, ByteBuff buf2, int o2, int len2)` Compares two ByteBuffs
`abstract ByteBuff`	`duplicate()` Returns an ByteBuff which is a duplicate version of this ByteBuff.
`abstract byte`	`get()` A relative method that returns byte at the current position.
`abstract void`	`get(byte[] dst)` Copies the content from this ByteBuff's current position to the byte array and fills it.
`abstract void`	`get(byte[] dst, int offset, int length)` Copies the specified number of bytes from this ByteBuff's current position to the byte[]'s offset.
`abstract void`	`get(ByteBuffer out, int sourceOffset, int length)` Copies the content from this ByteBuff to a ByteBuffer Note : This will advance the position marker of `out` but not change the position maker for this ByteBuff
`abstract byte`	`get(int index)` Fetches the byte at the given index.
`abstract void`	`get(int sourceOffset, byte[] dst, int offset, int length)` Copies the specified number of bytes from this ByteBuff's given position to the byte[]'s offset.
`abstract byte`	`getByteAfterPosition(int offset)` Fetches the byte at the given offset from current position.
`abstract int`	`getInt()` Returns the int value at the current position.
`abstract int`	`getInt(int index)` Fetches the int at the given index.
`abstract int`	`getIntAfterPosition(int offset)` Fetches the int value at the given offset from current position.
`abstract long`	`getLong()` Returns the long value at the current position.
`abstract long`	`getLong(int index)` Fetches the long at the given index.
`abstract long`	`getLongAfterPosition(int offset)` Fetches the long value at the given offset from current position.
`abstract short`	`getShort()` Returns the short value at the current position.
`abstract short`	`getShort(int index)` Fetches the short value at the given index.
`abstract short`	`getShortAfterPosition(int offset)` Fetches the short value at the given offset from current position.
`abstract boolean`	`hasArray()`
`abstract boolean`	`hasRemaining()` Returns true if there are elements between the current position and the limt
`abstract int`	`limit()` Returns the limit of this ByteBuff
`abstract ByteBuff`	`limit(int limit)` Marks the limit of this ByteBuff.
`abstract ByteBuff`	`mark()` Marks the current position of the ByteBuff
`abstract ByteBuff`	`moveBack(int len)` Jumps back the current position of this ByteBuff by specified length.
`abstract int`	`position()`
`abstract ByteBuff`	`position(int position)` Sets this ByteBuff's position to the given value.
`abstract ByteBuff`	`put(byte b)` Writes a byte to this ByteBuff at the current position and increments the position
`abstract ByteBuff`	`put(byte[] src)` Copies from the given byte[] to this ByteBuff
`abstract ByteBuff`	`put(byte[] src, int offset, int length)` Copies from the given byte[] to this ByteBuff
`abstract ByteBuff`	`put(int index, byte b)` Writes a byte to this ByteBuff at the given index
`abstract ByteBuff`	`put(int offset, ByteBuff src, int srcOffset, int length)` Copies the contents from the src ByteBuff to this ByteBuff.
`abstract ByteBuff`	`putInt(int value)` Writes an int to this ByteBuff at its current position.
`abstract ByteBuff`	`putLong(long value)` Writes a long to this ByteBuff at its current position.
`abstract int`	`read(ReadableByteChannel channel)` Reads bytes from the given channel into this ByteBuff
`static int`	`readCompressedInt(ByteBuff buf)` Read integer from ByteBuff coded in 7 bits and increment position.
`static long`	`readLong(ByteBuff in, int fitInBytes)` Read long which was written to fitInBytes bytes and increment position.
`static long`	`readVLong(ByteBuff in)` Similar to `WritableUtils.readVLong(java.io.DataInput)` but reads from a `ByteBuff`.
`abstract int`	`remaining()` Returns the number of elements between the current position and the limit.
`abstract ByteBuff`	`reset()` Similar to `ByteBuffer`.reset(), ensures that this ByteBuff is reset back to last marked position.
`abstract ByteBuff`	`rewind()` Rewinds this ByteBuff and the position is set to 0
`abstract ByteBuff`	`skip(int len)` Jumps the current position of this ByteBuff by specified length.
`abstract ByteBuff`	`slice()` Returns an ByteBuff which is a sliced version of this ByteBuff.
`byte[]`	`toBytes()` Copy the content from this ByteBuff to a byte[].
`abstract byte[]`	`toBytes(int offset, int length)` Copy the content from this ByteBuff to a byte[] based on the given offset and length
`String`	`toString()`
`static String`	`toStringBinary(ByteBuff b, int off, int len)`
`static int`	`unsignedBinarySearch(ByteBuff a, int fromIndex, int toIndex, byte key)` Search sorted array "a" for byte "key".

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

- Constructor Detail
  - ByteBuff
```
public ByteBuff()
```
- Method Detail
  - position
```
public abstract int position()
```
    Returns:
    
    this ByteBuff's current position
  - position
```
public abstract ByteBuff position(int position)
```
    Sets this ByteBuff's position to the given value.
    
    Parameters:
    
    position -
    
    Returns:
    
    this object
  - skip
```
public abstract ByteBuff skip(int len)
```
    Jumps the current position of this ByteBuff by specified length.
    
    Parameters:
    
    len - the length to be skipped
  - moveBack
```
public abstract ByteBuff moveBack(int len)
```
    Jumps back the current position of this ByteBuff by specified length.
    
    Parameters:
    
    len - the length to move back
  - capacity
```
public abstract int capacity()
```
    Returns:
    
    the total capacity of this ByteBuff.
  - limit
```
public abstract int limit()
```
    Returns the limit of this ByteBuff
    
    Returns:
    
    limit of the ByteBuff
  - limit
```
public abstract ByteBuff limit(int limit)
```
    Marks the limit of this ByteBuff.
    
    Parameters:
    
    limit -
    
    Returns:
    
    This ByteBuff
  - rewind
```
public abstract ByteBuff rewind()
```
    Rewinds this ByteBuff and the position is set to 0
    
    Returns:
    
    this object
  - mark
```
public abstract ByteBuff mark()
```
    Marks the current position of the ByteBuff
    
    Returns:
    
    this object
  - asSubByteBuffer
```
public abstract ByteBuffer asSubByteBuffer(int length)
```
    Returns bytes from current position till length specified, as a single ByteBuffer. When all these bytes happen to be in a single ByteBuffer, which this object wraps, that ByteBuffer item as such will be returned. So users are warned not to change the position or limit of this returned ByteBuffer. The position of the returned byte buffer is at the begin of the required bytes. When the required bytes happen to span across multiple ByteBuffers, this API will copy the bytes to a newly created ByteBuffer of required size and return that.
    
    Parameters:
    
    length - number of bytes required.
    
    Returns:
    
    bytes from current position till length specified, as a single ByteButter.
  - asSubByteBuffer
```
public abstract void asSubByteBuffer(int offset,
                                     int length,
                                     ObjectIntPair<ByteBuffer> pair)
```
    Returns bytes from given offset till length specified, as a single ByteBuffer. When all these bytes happen to be in a single ByteBuffer, which this object wraps, that ByteBuffer item as such will be returned (with offset in this ByteBuffer where the bytes starts). So users are warned not to change the position or limit of this returned ByteBuffer. When the required bytes happen to span across multiple ByteBuffers, this API will copy the bytes to a newly created ByteBuffer of required size and return that.
    
    Parameters:
    
    offset - the offset in this ByteBuff from where the subBuffer should be created
    
    length - the length of the subBuffer
    
    pair - a pair that will have the bytes from the current position till length specified, as a single ByteBuffer and offset in that Buffer where the bytes starts. Since this API gets called in a loop we are passing a pair to it which could be created outside the loop and the method would set the values on the pair that is passed in by the caller. Thus it avoids more object creations that would happen if the pair that is returned is created by this method every time.
  - remaining
```
public abstract int remaining()
```
    Returns the number of elements between the current position and the limit.
    
    Returns:
    
    the remaining elements in this ByteBuff
  - hasRemaining
```
public abstract boolean hasRemaining()
```
    Returns true if there are elements between the current position and the limt
    
    Returns:
    
    true if there are elements, false otherwise
  - reset
```
public abstract ByteBuff reset()
```
    Similar to ByteBuffer.reset(), ensures that this ByteBuff is reset back to last marked position.
    
    Returns:
    
    This ByteBuff
  - slice
```
public abstract ByteBuff slice()
```
    Returns an ByteBuff which is a sliced version of this ByteBuff. The position, limit and mark of the new ByteBuff will be independent than that of the original ByteBuff. The content of the new ByteBuff will start at this ByteBuff's current position
    
    Returns:
    
    a sliced ByteBuff
  - duplicate
```
public abstract ByteBuff duplicate()
```
    Returns an ByteBuff which is a duplicate version of this ByteBuff. The position, limit and mark of the new ByteBuff will be independent than that of the original ByteBuff. The content of the new ByteBuff will start at this ByteBuff's current position The position, limit and mark of the new ByteBuff would be identical to this ByteBuff in terms of values.
    
    Returns:
    
    a sliced ByteBuff
  - get
```
public abstract byte get()
```
    A relative method that returns byte at the current position. Increments the current position by the size of a byte.
    
    Returns:
    
    the byte at the current position
  - get
```
public abstract byte get(int index)
```
    Fetches the byte at the given index. Does not change position of the underlying ByteBuffers
    
    Parameters:
    
    index -
    
    Returns:
    
    the byte at the given index
  - getByteAfterPosition
```
public abstract byte getByteAfterPosition(int offset)
```
    Fetches the byte at the given offset from current position. Does not change position of the underlying ByteBuffers.
    
    Parameters:
    
    offset -
    
    Returns:
    
    the byte value at the given index.
  - put
```
public abstract ByteBuff put(byte b)
```
    Writes a byte to this ByteBuff at the current position and increments the position
    
    Parameters:
    
    b -
    
    Returns:
    
    this object
  - put
```
public abstract ByteBuff put(int index,
                             byte b)
```
    Writes a byte to this ByteBuff at the given index
    
    Parameters:
    
    index -
    
    b -
    
    Returns:
    
    this object
  - get
```
public abstract void get(byte[] dst,
                         int offset,
                         int length)
```
    Copies the specified number of bytes from this ByteBuff's current position to the byte[]'s offset. Also advances the position of the ByteBuff by the given length.
    
    Parameters:
    
    dst -
    
    offset - within the current array
    
    length - upto which the bytes to be copied
  - get
```
public abstract void get(int sourceOffset,
                         byte[] dst,
                         int offset,
                         int length)
```
    Copies the specified number of bytes from this ByteBuff's given position to the byte[]'s offset. The position of the ByteBuff remains in the current position only
    
    Parameters:
    
    sourceOffset - the offset in this ByteBuff from where the copy should happen
    
    dst - the byte[] to which the ByteBuff's content is to be copied
    
    offset - within the current array
    
    length - upto which the bytes to be copied
  - get
```
public abstract void get(byte[] dst)
```
    Copies the content from this ByteBuff's current position to the byte array and fills it. Also advances the position of the ByteBuff by the length of the byte[].
    
    Parameters:
    
    dst -
  - put
```
public abstract ByteBuff put(byte[] src,
                             int offset,
                             int length)
```
    Copies from the given byte[] to this ByteBuff
    
    Parameters:
    
    src -
    
    offset - the position in the byte array from which the copy should be done
    
    length - the length upto which the copy should happen
    
    Returns:
    
    this ByteBuff
  - put
```
public abstract ByteBuff put(byte[] src)
```
    Copies from the given byte[] to this ByteBuff
    
    Parameters:
    
    src -
    
    Returns:
    
    this ByteBuff
  - hasArray
```
public abstract boolean hasArray()
```
    Returns:
    
    true or false if the underlying BB support hasArray
  - array
```
public abstract byte[] array()
```
    Returns:
    
    the byte[] if the underlying BB has single BB and hasArray true
  - arrayOffset
```
public abstract int arrayOffset()
```
    Returns:
    
    the arrayOffset of the byte[] incase of a single BB backed ByteBuff
  - getShort
```
public abstract short getShort()
```
    Returns the short value at the current position. Also advances the position by the size of short
    
    Returns:
    
    the short value at the current position
  - getShort
```
public abstract short getShort(int index)
```
    Fetches the short value at the given index. Does not change position of the underlying ByteBuffers. The caller is sure that the index will be after the current position of this ByteBuff. So even if the current short does not fit in the current item we can safely move to the next item and fetch the remaining bytes forming the short
    
    Parameters:
    
    index -
    
    Returns:
    
    the short value at the given index
  - getShortAfterPosition
```
public abstract short getShortAfterPosition(int offset)
```
    Fetches the short value at the given offset from current position. Does not change position of the underlying ByteBuffers.
    
    Parameters:
    
    offset -
    
    Returns:
    
    the short value at the given index.
  - getInt
```
public abstract int getInt()
```
    Returns the int value at the current position. Also advances the position by the size of int
    
    Returns:
    
    the int value at the current position
  - putInt
```
public abstract ByteBuff putInt(int value)
```
    Writes an int to this ByteBuff at its current position. Also advances the position by size of int
    
    Parameters:
    
    value - Int value to write
    
    Returns:
    
    this object
  - getInt
```
public abstract int getInt(int index)
```
    Fetches the int at the given index. Does not change position of the underlying ByteBuffers. Even if the current int does not fit in the current item we can safely move to the next item and fetch the remaining bytes forming the int
    
    Parameters:
    
    index -
    
    Returns:
    
    the int value at the given index
  - getIntAfterPosition
```
public abstract int getIntAfterPosition(int offset)
```
    Fetches the int value at the given offset from current position. Does not change position of the underlying ByteBuffers.
    
    Parameters:
    
    offset -
    
    Returns:
    
    the int value at the given index.
  - getLong
```
public abstract long getLong()
```
    Returns the long value at the current position. Also advances the position by the size of long
    
    Returns:
    
    the long value at the current position
  - putLong
```
public abstract ByteBuff putLong(long value)
```
    Writes a long to this ByteBuff at its current position. Also advances the position by size of long
    
    Parameters:
    
    value - Long value to write
    
    Returns:
    
    this object
  - getLong
```
public abstract long getLong(int index)
```
    Fetches the long at the given index. Does not change position of the underlying ByteBuffers. The caller is sure that the index will be after the current position of this ByteBuff. So even if the current long does not fit in the current item we can safely move to the next item and fetch the remaining bytes forming the long
    
    Parameters:
    
    index -
    
    Returns:
    
    the long value at the given index
  - getLongAfterPosition
```
public abstract long getLongAfterPosition(int offset)
```
    Fetches the long value at the given offset from current position. Does not change position of the underlying ByteBuffers.
    
    Parameters:
    
    offset -
    
    Returns:
    
    the long value at the given index.
  - toBytes
```
public byte[] toBytes()
```
    Copy the content from this ByteBuff to a byte[].
    
    Returns:
    
    byte[] with the copied contents from this ByteBuff.
  - toBytes
```
public abstract byte[] toBytes(int offset,
                               int length)
```
    Copy the content from this ByteBuff to a byte[] based on the given offset and length
    
    Parameters:
    
    offset - the position from where the copy should start
    
    length - the length upto which the copy has to be done
    
    Returns:
    
    byte[] with the copied contents from this ByteBuff.
  - get
```
public abstract void get(ByteBuffer out,
                         int sourceOffset,
                         int length)
```
    Copies the content from this ByteBuff to a ByteBuffer Note : This will advance the position marker of out but not change the position maker for this ByteBuff
    
    Parameters:
    
    out - the ByteBuffer to which the copy has to happen
    
    sourceOffset - the offset in the ByteBuff from which the elements has to be copied
    
    length - the length in this ByteBuff upto which the elements has to be copied
  - put
```
public abstract ByteBuff put(int offset,
                             ByteBuff src,
                             int srcOffset,
                             int length)
```
    Copies the contents from the src ByteBuff to this ByteBuff. This will be absolute positional copying and won't affect the position of any of the buffers.
    
    Parameters:
    
    offset - the position in this ByteBuff to which the copy should happen
    
    src - the src ByteBuff
    
    srcOffset - the offset in the src ByteBuff from where the elements should be read
    
    length - the length up to which the copy should happen
  - read
```
public abstract int read(ReadableByteChannel channel)
                  throws IOException
```
    Reads bytes from the given channel into this ByteBuff
    
    Parameters:
    
    channel -
    
    Returns:
    
    The number of bytes read from the channel
    
    Throws:
    
    IOException
  - channelRead
```
public static int channelRead(ReadableByteChannel channel,
                              ByteBuffer buf)
                       throws IOException
```
    Throws:
    
    IOException
  - readCompressedInt
```
public static int readCompressedInt(ByteBuff buf)
```
    Read integer from ByteBuff coded in 7 bits and increment position.
    
    Returns:
    
    Read integer.
  - compareTo
```
public static int compareTo(ByteBuff buf1,
                            int o1,
                            int len1,
                            ByteBuff buf2,
                            int o2,
                            int len2)
```
    Compares two ByteBuffs
    
    Parameters:
    
    buf1 - the first ByteBuff
    
    o1 - the offset in the first ByteBuff from where the compare has to happen
    
    len1 - the length in the first ByteBuff upto which the compare has to happen
    
    buf2 - the second ByteBuff
    
    o2 - the offset in the second ByteBuff from where the compare has to happen
    
    len2 - the length in the second ByteBuff upto which the compare has to happen
    
    Returns:
    
    Positive if buf1 is bigger than buf2, 0 if they are equal, and negative if buf1 is smaller than buf2.
  - readLong
```
public static long readLong(ByteBuff in,
                            int fitInBytes)
```
    Read long which was written to fitInBytes bytes and increment position.
    
    Parameters:
    
    fitInBytes - In how many bytes given long is stored.
    
    Returns:
    
    The value of parsed long.
  - readVLong
```
public static long readVLong(ByteBuff in)
```
    Similar to WritableUtils.readVLong(java.io.DataInput) but reads from a ByteBuff.
  - unsignedBinarySearch
```
public static int unsignedBinarySearch(ByteBuff a,
                                       int fromIndex,
                                       int toIndex,
                                       byte key)
```
    Search sorted array "a" for byte "key".
    
    Parameters:
    
    a - Array to search. Entries must be sorted and unique.
    
    fromIndex - First index inclusive of "a" to include in the search.
    
    toIndex - Last index exclusive of "a" to include in the search.
    
    key - The byte to search for.
    
    Returns:
    
    The index of key if found. If not found, return -(index + 1), where negative indicates "not found" and the "index + 1" handles the "-0" case.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - toStringBinary
```
public static String toStringBinary(ByteBuff b,
                                    int off,
                                    int len)
```

Class ByteBuff

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ByteBuff

Method Detail

position

position

skip

moveBack

capacity

limit

limit

rewind

mark

asSubByteBuffer

asSubByteBuffer

remaining

hasRemaining

reset

slice

duplicate

get

get

getByteAfterPosition

put

put

get

get

get

put

put

hasArray

array

arrayOffset

getShort

getShort

getShortAfterPosition

getInt

putInt

getInt

getIntAfterPosition

getLong

putLong

getLong

getLongAfterPosition

toBytes

toBytes

get

put

read

channelRead

readCompressedInt

compareTo

readLong

readVLong

unsignedBinarySearch

toString

toStringBinary