Package org.apache.storm.utils

Class WritableUtils

java.lang.Object

org.apache.storm.utils.WritableUtils

public final class WritableUtils
extends Object

Constructor Summary

Constructors

Constructor	Description
WritableUtils()

Method Summary

Modifier and Type	Method	Description
static int	decodeVIntSize(byte value)	Parse the first byte of a vint/vlong to determine the number of bytes.
static void	displayByteArray(byte[] record)	Test Utility Method Display Byte Array.
static int	getVIntSize(long i)	Get the encoded length if an integer is stored in a variable-length format.
static boolean	isNegativeVInt(byte value)	Given the first byte of a vint/vlong, determine the sign.
static byte[]	readCompressedByteArray(DataInput in)
static String	readCompressedString(DataInput in)	Ugly utility, maybe someone else can do this better.
static String[]	readCompressedStringArray(DataInput in)	Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
static String	readString(DataInput in)	Read a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF.
static String[]	readStringArray(DataInput in)	Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
static int	readVInt(DataInput stream)	Reads a zero-compressed encoded integer from input stream and returns it.
static long	readVLong(DataInput stream)	Reads a zero-compressed encoded long from input stream and returns it.
static void	skipCompressedByteArray(DataInput in)
static void	skipFully(DataInput in, int len)	Skip len number of bytes in input streamin.
static int	writeCompressedByteArray(DataOutput out, byte[] bytes)
static int	writeCompressedString(DataOutput out, String s)
static void	writeCompressedStringArray(DataOutput out, String[] s)
static void	writeString(DataOutput out, String s)	Write a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF.
static void	writeStringArray(DataOutput out, String[] s)	Write a String array as a Nework Int N, followed by Int N Byte Array Strings.
static void	writeVInt(DataOutput stream, int i)	Serializes an integer to a binary stream with zero-compressed encoding.
static void	writeVLong(DataOutput stream, long i)	Serializes a long to a binary stream with zero-compressed encoding.

Methods inherited from class java.lang.Object

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

Constructor Detail

WritableUtils

public WritableUtils()

Method Detail

readCompressedByteArray

public static byte[] readCompressedByteArray(DataInput in)
                                      throws IOException

Throws:

IOException

skipCompressedByteArray

public static void skipCompressedByteArray(DataInput in)
                                    throws IOException

Throws:

IOException

writeCompressedByteArray

public static int writeCompressedByteArray(DataOutput out,
                                           byte[] bytes)
                                    throws IOException

Throws:

IOException

readCompressedString

public static String readCompressedString(DataInput in)
                                   throws IOException

Ugly utility, maybe someone else can do this better.

Throws:

IOException

writeCompressedString

public static int writeCompressedString(DataOutput out,
                                        String s)
                                 throws IOException

Throws:

IOException

writeString

public static void writeString(DataOutput out,
                               String s)
                        throws IOException

Write a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF. Encoding standard is... ?

Throws:

IOException

readString

public static String readString(DataInput in)
                         throws IOException

Read a String as a Network Int n, followed by n Bytes Alternative to 16 bit read/writeUTF. Encoding standard is... ?

Throws:

IOException

writeStringArray

public static void writeStringArray(DataOutput out,
                                    String[] s)
                             throws IOException

Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection.

Throws:

IOException

writeCompressedStringArray

public static void writeCompressedStringArray(DataOutput out,
                                              String[] s)
                                       throws IOException

Throws:

IOException

readStringArray

public static String[] readStringArray(DataInput in)
                                throws IOException

Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection. Actually this bit couldn't...

Throws:

IOException

readCompressedStringArray

public static String[] readCompressedStringArray(DataInput in)
                                          throws IOException

Write a String array as a Nework Int N, followed by Int N Byte Array Strings. Could be generalised using introspection. Handles null arrays and null values.

Throws:

IOException

displayByteArray

public static void displayByteArray(byte[] record)

Test Utility Method Display Byte Array.

writeVInt

public static void writeVInt(DataOutput stream,
                             int i)
                      throws IOException

Serializes an integer to a binary stream with zero-compressed encoding. For -120 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the integer is positive or negative, and the number of bytes that follow. If the first byte value v is between -121 and -124, the following integer is positive, with number of bytes that follow are -(v+120). If the first byte value v is between -125 and -128, the following integer is negative, with number of bytes that follow are -(v+124). Bytes are stored in the high-non-zero-byte-first order.

Parameters:

stream - Binary output stream

i - Integer to be serialized

Throws:

IOException

writeVLong

public static void writeVLong(DataOutput stream,
                              long i)
                       throws IOException

Serializes a long to a binary stream with zero-compressed encoding. For -112 <= i <= 127, only one byte is used with the actual value. For other values of i, the first byte value indicates whether the long is positive or negative, and the number of bytes that follow. If the first byte value v is between -113 and -120, the following long is positive, with number of bytes that follow are -(v+112). If the first byte value v is between -121 and -128, the following long is negative, with number of bytes that follow are -(v+120). Bytes are stored in the high-non-zero-byte-first order.

Parameters:

stream - Binary output stream

i - Long to be serialized

Throws:

IOException

readVLong

public static long readVLong(DataInput stream)
                      throws IOException

Reads a zero-compressed encoded long from input stream and returns it.

Parameters:

stream - Binary input stream

Returns:

deserialized long from stream.

Throws:

IOException

readVInt

public static int readVInt(DataInput stream)
                    throws IOException

Reads a zero-compressed encoded integer from input stream and returns it.

Parameters:

stream - Binary input stream

Returns:

deserialized integer from stream.

Throws:

IOException

isNegativeVInt

public static boolean isNegativeVInt(byte value)

Given the first byte of a vint/vlong, determine the sign.

Parameters:

value - the first byte

Returns:

is the value negative

decodeVIntSize

public static int decodeVIntSize(byte value)

Parse the first byte of a vint/vlong to determine the number of bytes.

Parameters:

value - the first byte of the vint/vlong

Returns:

the total number of bytes (1 to 9)

getVIntSize

public static int getVIntSize(long i)

Get the encoded length if an integer is stored in a variable-length format.

Returns:

the encoded length

skipFully

public static void skipFully(DataInput in,
                             int len)
                      throws IOException

Skip len number of bytes in input streamin.

Parameters:

in - input stream

len - number of bytes to skip

Throws:

IOException - when skipped less number of bytes