Package org.apache.hadoop.hbase.io

Class ImmutableBytesWritable

java.lang.Object

org.apache.hadoop.hbase.io.ImmutableBytesWritable

All Implemented Interfaces:

Comparable<ImmutableBytesWritable>, org.apache.hadoop.io.Writable, org.apache.hadoop.io.WritableComparable<ImmutableBytesWritable>

@Public
public class ImmutableBytesWritable
extends Object
implements org.apache.hadoop.io.WritableComparable<ImmutableBytesWritable>

A byte sequence that is usable as a key or value. Based on BytesWritable only this class is NOT resizable and DOES NOT distinguish between the size of the sequence and the current capacity as BytesWritable does. Hence its comparatively 'immutable'. When creating a new instance of this class, the underlying byte [] is not copied, just referenced. The backing buffer is accessed when we go to serialize.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ImmutableBytesWritable.Comparator	A Comparator optimized for ImmutableBytesWritable.

Field Summary

Fields

Modifier and Type	Field	Description
private byte[]	bytes
private int	length
private int	offset

Constructor Summary

Constructors

Constructor	Description
ImmutableBytesWritable()	Create a zero-size sequence.
ImmutableBytesWritable(byte[] bytes)	Create a ImmutableBytesWritable using the byte array as the initial value.
ImmutableBytesWritable(byte[] bytes, int offset, int length)	Set the value to a given byte range
ImmutableBytesWritable(ImmutableBytesWritable ibw)	Set the new ImmutableBytesWritable to the contents of the passed ibw.

Method Summary

Modifier and Type	Method	Description
int	compareTo(byte[] that)	Compares the bytes in this object to the specified byte array
int	compareTo(ImmutableBytesWritable that)	Define the sort order of the BytesWritable.
byte[]	copyBytes()	Returns a copy of the bytes referred to by this writable
boolean	equals(Object right_obj)
byte[]	get()	Get the data from the BytesWritable.
int	getLength()	Returns the number of valid bytes in the buffer
int	getOffset()	Return the offset into the buffer.
int	hashCode()
void	readFields(DataInput in)
void	set(byte[] b)	Use passed bytes as backing array for this instance.
void	set(byte[] b, int offset, int length)	Use passed bytes as backing array for this instance.
static byte[][]	toArray(List<byte[]> array)	Convert a list of byte arrays into an array of byte arrays
String	toString()
void	write(DataOutput out)

Methods inherited from class java.lang.Object

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

Field Details

bytes

private byte[] bytes

offset

private int offset

length

private int length

Constructor Details

ImmutableBytesWritable

public ImmutableBytesWritable()

Create a zero-size sequence.

ImmutableBytesWritable

public ImmutableBytesWritable(byte[] bytes)

Create a ImmutableBytesWritable using the byte array as the initial value.

Parameters:

bytes - This array becomes the backing storage for the object.

ImmutableBytesWritable

public ImmutableBytesWritable(ImmutableBytesWritable ibw)

Set the new ImmutableBytesWritable to the contents of the passed ibw.

Parameters:

ibw - the value to set this ImmutableBytesWritable to.

ImmutableBytesWritable

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

Set the value to a given byte range

Parameters:

bytes - the new byte range to set to

offset - the offset in newData to start at

length - the number of bytes in the range

Method Details

get

public byte[] get()

Get the data from the BytesWritable.

Returns:

The data is only valid between offset and offset+length.

set

public void set(byte[] b)

Use passed bytes as backing array for this instance.

set

public void set(byte[] b,
 int offset,
 int length)

Use passed bytes as backing array for this instance.

getLength

public int getLength()

Returns the number of valid bytes in the buffer

getOffset

public int getOffset()

Return the offset into the buffer.

readFields

public void readFields(DataInput in)
                throws IOException

Specified by:

readFields in interface org.apache.hadoop.io.Writable

Throws:

IOException

write

public void write(DataOutput out)
           throws IOException

Specified by:

write in interface org.apache.hadoop.io.Writable

Throws:

IOException

hashCode

public int hashCode()

Overrides:

hashCode in class Object

compareTo

public int compareTo(ImmutableBytesWritable that)

Define the sort order of the BytesWritable.

Specified by:

compareTo in interface Comparable<ImmutableBytesWritable>

Parameters:

that - The other bytes writable

Returns:

Positive if left is bigger than right, 0 if they are equal, and negative if left is smaller than right.

compareTo

public int compareTo(byte[] that)

Compares the bytes in this object to the specified byte array

Returns:

Positive if left is bigger than right, 0 if they are equal, and negative if left is smaller than right.

equals

public boolean equals(Object right_obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

toArray

public static byte[][] toArray(List<byte[]> array)

Convert a list of byte arrays into an array of byte arrays

Parameters:

array - List of byte [].

Returns:

Array of byte [].

copyBytes

public byte[] copyBytes()

Returns a copy of the bytes referred to by this writable