com.sun.sgs.impl.sharedutil

Class MessageBuffer

java.lang.Object

com.sun.sgs.impl.sharedutil.MessageBuffer

public class MessageBuffer
extends Object

A buffer for composing/decomposing messages.

Strings are encoded in modified UTF-8 format as described in DataInput.

Constructor Summary

Constructors

Constructor and Description
MessageBuffer(byte[] buf) Constructs a message buffer using the specified byte array as the byte array that backs this buffer.
MessageBuffer(int capacity) Constructs an empty message buffer with the specified capacity.

Method Summary

Methods

Modifier and Type	Method and Description
int	capacity() Returns the capacity of this buffer.
byte[]	getBuffer() Returns the byte array that backs this buffer.
byte	getByte() Returns the byte in this buffer's current position, and advances the buffer's position by one.
byte[]	getByteArray() Returns a byte array encoded as a 2-byte length followed by the bytes, starting at this buffer's current position, and advances the buffer's position by the number of bytes obtained.
byte[]	getBytes(int size) Returns a byte array containing the specified number of bytes, starting at this buffer's current position, and advances the buffer's position by the number of bytes obtained.
char	getChar() Returns a char, composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two.
int	getInt() Returns an int value, composed of the next four bytes (high byte first) in this buffer, and advances the buffer's position by 4.
long	getLong() Returns a long value, composed of the next eight bytes (high byte first) in this buffer, and advances the buffer's position by 8.
short	getShort() Returns a short value, composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two.
static int	getSize(String str) Returns the size of the specified string, encoded in modified UTF-8 format.
String	getString() Returns a string that has been encoded in modified UTF-8 format, starting at the buffer's current position, and advances the buffer's position by the length of the encoded string.
int	getUnsignedShort() Returns an unsigned short value (as an int), composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two.
int	limit() Returns the limit of this buffer.
int	position() Returns the position of this buffer.
MessageBuffer	putByte(int b) Puts the specified byte in this buffer's current position, and advances the buffer's position and limit by one.
MessageBuffer	putByteArray(byte[] bytes) Puts into this buffer a short representing the length of the specified byte array followed by the bytes from the specified byte array, starting at the buffer's current position.
MessageBuffer	putBytes(byte[] bytes) Puts the bytes from the specified byte array in this buffer, starting at the buffer's current position.
MessageBuffer	putChar(int v) Puts the specified char as a two-byte value (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by two.
MessageBuffer	putInt(int v) Puts the specified int as four bytes (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by 4.
MessageBuffer	putLong(long v) Puts the specified long as eight bytes (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by 8.
MessageBuffer	putShort(int v) Puts the specified short as a two-byte value (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by two.
MessageBuffer	putString(String str) Puts the specified string, encoded in modified UTF-8 format, in the buffer starting in the buffer's the current position, and advances the buffer's position and limit by the size of the encoded string.
void	rewind() Sets the position of this buffer to zero, making this buffer ready for re-reading of its elements.

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageBuffer

public MessageBuffer(int capacity)

Constructs an empty message buffer with the specified capacity.

Parameters:

capacity - the buffer's capacity

MessageBuffer

public MessageBuffer(byte[] buf)

Constructs a message buffer using the specified byte array as the byte array that backs this buffer. Intializes this buffer's capacity and limit to the length of the specified byte array.

Parameters:

buf - the byte array to back this buffer

Method Detail

getSize

public static int getSize(String str)

Returns the size of the specified string, encoded in modified UTF-8 format.

Parameters:

str - a string

Returns:

the size of the specified string, encoded in modified UTF-8 format

capacity

public int capacity()

Returns the capacity of this buffer. The capacity is the number of elements this buffer contains.

Returns:

this buffer's capacity

limit

public int limit()

Returns the limit of this buffer. The limit is the index of the first element that should not be written or read. The limit is never negative and is never greater than the buffer's capacity.

Returns:

this buffer's limit

position

public int position()

Returns the position of this buffer. The position is the index of the next element to be written or read.

Returns:

this buffer's position

rewind

public void rewind()

Sets the position of this buffer to zero, making this buffer ready for re-reading of its elements.

putByte

public MessageBuffer putByte(int b)

Puts the specified byte in this buffer's current position, and advances the buffer's position and limit by one.

Parameters:

b - a byte

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the byte to the buffer would overflow the buffer

putByteArray

public MessageBuffer putByteArray(byte[] bytes)

Puts into this buffer a short representing the length of the specified byte array followed by the bytes from the specified byte array, starting at the buffer's current position. The buffer's position and limit are advanced by the length of the specified byte array plus two.

Parameters:

bytes - a byte array

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the bytes to this buffer would overflow the buffer

putBytes

public MessageBuffer putBytes(byte[] bytes)

Puts the bytes from the specified byte array in this buffer, starting at the buffer's current position. The buffer's position and limit are advanced by the length of the specified byte array.

Parameters:

bytes - a byte array

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the bytes to this buffer would overflow the buffer

putChar

public MessageBuffer putChar(int v)

Puts the specified char as a two-byte value (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by two.

Parameters:

v - a char value

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the char to this buffer would overflow the buffer

putShort

public MessageBuffer putShort(int v)

Puts the specified short as a two-byte value (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by two.

Parameters:

v - a short value

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the short to this buffer would overflow the buffer

putInt

public MessageBuffer putInt(int v)

Puts the specified int as four bytes (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by 4.

Parameters:

v - an int value

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the int to this buffer would overflow the buffer

putLong

public MessageBuffer putLong(long v)

Puts the specified long as eight bytes (high byte first) starting in the buffer's current position, and advances the buffer's position and limit by 8.

Parameters:

v - a long value

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the long to this buffer would overflow the buffer

putString

public MessageBuffer putString(String str)

Puts the specified string, encoded in modified UTF-8 format, in the buffer starting in the buffer's the current position, and advances the buffer's position and limit by the size of the encoded string.

Parameters:

str - a string

Returns:

this buffer

Throws:

IndexOutOfBoundsException - if adding the encoded string to this buffer would overflow the buffer

getByte

public byte getByte()

Returns the byte in this buffer's current position, and advances the buffer's position by one.

Returns:

the byte at the buffer's current position

Throws:

IndexOutOfBoundsException - if this buffer's limit has been reached

getByteArray

public byte[] getByteArray()

Returns a byte array encoded as a 2-byte length followed by the bytes, starting at this buffer's current position, and advances the buffer's position by the number of bytes obtained.

Returns:

a byte array with the bytes from this buffer

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the encoded bytes

getBytes

public byte[] getBytes(int size)

Returns a byte array containing the specified number of bytes, starting at this buffer's current position, and advances the buffer's position by the number of bytes obtained.

Parameters:

size - the number of bytes to get from this buffer

Returns:

a byte array with the bytes from this buffer

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the specified number of bytes

getShort

public short getShort()

Returns a short value, composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two.

Returns:

the short value

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the next two bytes

getUnsignedShort

public int getUnsignedShort()

Returns an unsigned short value (as an int), composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two. The value returned is between 0 and 65535, inclusive.

Returns:

the unsigned short value as an int between 0 and 65535

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the next two bytes

getInt

public int getInt()

Returns an int value, composed of the next four bytes (high byte first) in this buffer, and advances the buffer's position by 4.

Returns:

the int value

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the next four bytes

getLong

public long getLong()

Returns a long value, composed of the next eight bytes (high byte first) in this buffer, and advances the buffer's position by 8.

Returns:

the long value

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the next eight bytes

getChar

public char getChar()

Returns a char, composed of the next two bytes (high byte first) in this buffer, and advances the buffer's position by two.

Returns:

the char

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the next two bytes

getString

public String getString()

Returns a string that has been encoded in modified UTF-8 format, starting at the buffer's current position, and advances the buffer's position by the length of the encoded string.

Returns:

the string

Throws:

IndexOutOfBoundsException - if this buffer's limit would be reached as a result of getting the encoded string

getBuffer

public byte[] getBuffer()

Returns the byte array that backs this buffer.

Returns:

the byte array that backs this buffer