com.nhncorp.neptune.common.io
Class NWritableComparator

java.lang.Object
  com.nhncorp.neptune.common.io.NWritableComparator

All Implemented Interfaces:

java.util.Comparator

Direct Known Subclasses:

NText.Comparator, NUTF8.Comparator

public class NWritableComparator
extends java.lang.Object
implements java.util.Comparator

A Comparator for NWritableComparables.

This base implemenation uses the natural ordering. To define alternate orderings, override compare(NWritableComparable,NWritableComparable).

One may optimize compare-intensive operations by overriding compare(byte[],int,int,byte[],int,int). Static utility methods are provided to assist in optimized implementations of this method.

Method Summary

int	compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) Optimization hook.
int	compare(NWritableComparable a, NWritableComparable b) Compare two WritableComparables.
int	compare(java.lang.Object a, java.lang.Object b)
static int	compareBytes(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) Lexicographic order of binary data.
static void	define(java.lang.Class c, NWritableComparator comparator) Register an optimized comparator for a NWritableComparable implementation.
static NWritableComparator	get(java.lang.Class c) Get a comparator for a NWritableComparable implementation.
java.lang.Class	getKeyClass() Returns the WritableComparable implementation class.
static int	hashBytes(byte[] bytes, int length) Compute hash for binary data.
NWritableComparable	newKey() Construct a new NWritableComparable instance.
static double	readDouble(byte[] bytes, int start) Parse a double from a byte array.
static float	readFloat(byte[] bytes, int start) Parse a float from a byte array.
static int	readInt(byte[] bytes, int start) Parse an integer from a byte array.
static long	readLong(byte[] bytes, int start) Parse a long from a byte array.
static int	readUnsignedShort(byte[] bytes, int start) Parse an unsigned short from a byte array.
static int	readVInt(byte[] bytes, int start) Reads a zero-compressed encoded integer from a byte array and returns it.
static long	readVLong(byte[] bytes, int start) Reads a zero-compressed encoded long from a byte array and returns it.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals

Method Detail

get

public static NWritableComparator get(java.lang.Class c)

Get a comparator for a NWritableComparable implementation.

define

public static void define(java.lang.Class c,
                          NWritableComparator comparator)

Register an optimized comparator for a NWritableComparable implementation.

getKeyClass

public java.lang.Class getKeyClass()

Returns the WritableComparable implementation class.

newKey

public NWritableComparable newKey()

Construct a new NWritableComparable instance.

compare

public int compare(byte[] b1,
                   int s1,
                   int l1,
                   byte[] b2,
                   int s2,
                   int l2)

Optimization hook. Override this to make SequenceFile.Sorter's scream.

The default implementation reads the data into two NWritableComparables (using NWritable.readFields(DataInput), then calls compare(NWritableComparable,NWritableComparable).

compare

public int compare(NWritableComparable a,
                   NWritableComparable b)

Compare two WritableComparables.

The default implementation uses the natural ordering, calling Comparable.compareTo(Object).

compare

public int compare(java.lang.Object a,
                   java.lang.Object b)

Specified by:

compare in interface java.util.Comparator

compareBytes

public static int compareBytes(byte[] b1,
                               int s1,
                               int l1,
                               byte[] b2,
                               int s2,
                               int l2)

Lexicographic order of binary data.

hashBytes

public static int hashBytes(byte[] bytes,
                            int length)

Compute hash for binary data.

readUnsignedShort

public static int readUnsignedShort(byte[] bytes,
                                    int start)

Parse an unsigned short from a byte array.

readInt

public static int readInt(byte[] bytes,
                          int start)

Parse an integer from a byte array.

readFloat

public static float readFloat(byte[] bytes,
                              int start)

Parse a float from a byte array.

readLong

public static long readLong(byte[] bytes,
                            int start)

Parse a long from a byte array.

readDouble

public static double readDouble(byte[] bytes,
                                int start)

Parse a double from a byte array.

readVLong

public static long readVLong(byte[] bytes,
                             int start)
                      throws java.io.IOException

Reads a zero-compressed encoded long from a byte array and returns it.

Parameters:

bytes - byte array with decode long

start - starting index

Returns:

deserialized long

Throws:

java.io.IOException

readVInt

public static int readVInt(byte[] bytes,
                           int start)
                    throws java.io.IOException

Reads a zero-compressed encoded integer from a byte array and returns it.

Parameters:

bytes - byte array with the encoded integer

start - start index

Returns:

deserialized integer

Throws:

java.io.IOException