org.apache.hadoop.hbase.util
Class ByteRange

java.lang.Object
  org.apache.hadoop.hbase.util.ByteRange

All Implemented Interfaces:

Comparable<ByteRange>

public class ByteRange
extends Object
implements Comparable<ByteRange>

Lightweight, reusable class for specifying ranges of byte[]'s. CompareTo and equals methods are lexicographic, which is native to HBase.

This class differs from ByteBuffer:

On-heap bytes only

Implements equals, hashCode, and compareTo so that it can be used in standard java Collections, similar to String.

Does not maintain mark/position iterator state inside the class. Doing so leads to many bugs in complex applications.

Allows the addition of simple core methods like this.copyTo(that, offset).

Can be reused in tight loops like a major compaction which can save significant amounts of garbage.

(Without reuse, we throw off garbage like this thing: http://www.youtube.com/watch?v=lkmBH-MjZF4

Mutable, and always evaluates equals, hashCode, and compareTo based on the current contents.

Can contain convenience methods for comparing, printing, cloning, spawning new arrays, copying to other arrays, etc. Please place non-core methods into ByteRangeTool.

We may consider converting this to an interface and creating separate implementations for a single byte[], a paged byte[] (growable byte[][]), a ByteBuffer, etc

Constructor Summary

ByteRange()
construct

ByteRange(byte[] bytes)

ByteRange(byte[] bytes, int offset, int length)

Method Summary

ByteRange	clear() write methods
int	compareTo(ByteRange other) Bitwise comparison of each byte in the array.
ByteRange	deepCopy() Create a new ByteRange with new backing byte[] and copy the state of this range into the new range.
void	deepCopySubRangeTo(int innerOffset, int copyLength, byte[] destination, int destinationOffset) Wrapper for System.arraycopy.
void	deepCopyTo(byte[] destination, int destinationOffset) Wrapper for System.arraycopy.
byte[]	deepCopyToNewArray() Instantiate a new byte[] with exact length, which is at least 24 bytes + length.
boolean	equals(Object thatObject) standard methods
byte	get(int index)
byte[]	getBytes()
int	getLength()
int	getOffset()
int	hashCode()
boolean	isEmpty()
static boolean	isEmpty(ByteRange range) static methods
boolean	notEmpty()
static boolean	notEmpty(ByteRange range)
int	numEqualPrefixBytes(ByteRange that, int thatInnerOffset)
ByteRange	set(byte[] bytes)
ByteRange	set(byte[] bytes, int offset, int length)
void	setLength(int length)
ByteRange	shallowCopySubRange(int innerOffset, int copyLength) Create a new ByteRange that points at this range's byte[].
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ByteRange

public ByteRange()

construct

ByteRange

public ByteRange(byte[] bytes)

ByteRange

public ByteRange(byte[] bytes,
                 int offset,
                 int length)

Method Detail

clear

public ByteRange clear()

write methods

set

public ByteRange set(byte[] bytes)

set

public ByteRange set(byte[] bytes,
                     int offset,
                     int length)

setLength

public void setLength(int length)

get

public byte get(int index)

Parameters:

index - zero-based index

Returns:

single byte at index

deepCopyToNewArray

public byte[] deepCopyToNewArray()

Instantiate a new byte[] with exact length, which is at least 24 bytes + length. Copy the contents of this range into it.

Returns:

The newly cloned byte[].

deepCopy

public ByteRange deepCopy()

Create a new ByteRange with new backing byte[] and copy the state of this range into the new range. Copy the hash over if it is already calculated.

Returns:

Deep copy

deepCopyTo

public void deepCopyTo(byte[] destination,
                       int destinationOffset)

Wrapper for System.arraycopy. Copy the contents of this range into the provided array.

Parameters:

destination - Copy to this array

destinationOffset - First index in the destination array.

deepCopySubRangeTo

public void deepCopySubRangeTo(int innerOffset,
                               int copyLength,
                               byte[] destination,
                               int destinationOffset)

Wrapper for System.arraycopy. Copy the contents of this range into the provided array.

Parameters:

innerOffset - Start copying from this index in this source ByteRange. First byte copied is bytes[offset + innerOffset]

copyLength - Copy this many bytes

destination - Copy to this array

destinationOffset - First index in the destination array.

shallowCopySubRange

public ByteRange shallowCopySubRange(int innerOffset,
                                     int copyLength)

Create a new ByteRange that points at this range's byte[]. The new range can have different values for offset and length, but modifying the shallowCopy will modify the bytes in this range's array. Pass over the hash code if it is already cached.

Parameters:

innerOffset - First byte of clone will be this.offset + copyOffset.

copyLength - Number of bytes in the clone.

Returns:

new ByteRange object referencing this range's byte[].

numEqualPrefixBytes

public int numEqualPrefixBytes(ByteRange that,
                               int thatInnerOffset)

getBytes

public byte[] getBytes()

getOffset

public int getOffset()

getLength

public int getLength()

isEmpty

public boolean isEmpty()

notEmpty

public boolean notEmpty()

isEmpty

public static boolean isEmpty(ByteRange range)

static methods

notEmpty

public static boolean notEmpty(ByteRange range)

equals

public boolean equals(Object thatObject)

standard methods

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(ByteRange other)

Bitwise comparison of each byte in the array. Unsigned comparison, not paying attention to java's signed bytes.

Specified by:

compareTo in interface Comparable<ByteRange>

toString

public String toString()

Overrides:

toString in class Object