Package edu.rit.mp

Package edu.rit.mp contains the Message Protocol (MP), a transport layer protocol for sending messages using TCP.

See: Description

Interface Summary

Interface	Description
ConnectListener	Interface ConnectListener specifies the interface for an object that is notified whenever a Channel is connected in a ChannelGroup.

Class Summary

Class	Description
BooleanBuf	Class BooleanBuf is the abstract base class for a buffer of Boolean items sent or received using the Message Protocol (MP).
Buf	Class Buf is the abstract base class for a buffer of items sent or received using the Message Protocol (MP).
ByteBuf	Class ByteBuf is the abstract base class for a buffer of byte items sent or received using the Message Protocol (MP).
Channel	Class Channel provides a channel for sending and receiving messages in the Message Protocol (MP).
ChannelGroup	Class ChannelGroup provides a group of Channels for sending and receiving messages in the Message Protocol (MP).
CharacterBuf	Class CharacterBuf is the abstract base class for a buffer of character items sent or received using the Message Protocol (MP).
DoubleBuf	Class DoubleBuf is the abstract base class for a buffer of double items sent or received using the Message Protocol (MP).
FloatBuf	Class FloatBuf is the abstract base class for a buffer of float items sent or received using the Message Protocol (MP).
IntegerBuf	Class IntegerBuf is the abstract base class for a buffer of integer items sent or received using the Message Protocol (MP).
IORequest	Class IORequest encapsulates the state of a message being sent or received in the Message Protocol (MP).
LongBuf	Class LongBuf is the abstract base class for a buffer of long items sent or received using the Message Protocol (MP).
ObjectBuf<T>	Class ObjectBuf is the abstract base class for a buffer of object items sent or received using the Message Protocol (MP).
ShortBuf	Class ShortBuf is the abstract base class for a buffer of short items sent or received using the Message Protocol (MP).
Signed16BitIntegerBuf	Class Signed16BitIntegerBuf is the abstract base class for a buffer of signed 16-bit integer items sent or received using the Message Protocol (MP).
Signed8BitIntegerBuf	Class Signed8BitIntegerBuf is the abstract base class for a buffer of signed 8-bit integer items sent or received using the Message Protocol (MP).
Status	Class Status provides the result of receiving a message in the Message Protocol (MP).
Unsigned16BitIntegerBuf	Class Unsigned16BitIntegerBuf is the abstract base class for a buffer of unsigned 16-bit integer items sent or received using the Message Protocol (MP).
Unsigned8BitIntegerBuf	Class Unsigned8BitIntegerBuf is the abstract base class for a buffer of unsigned 8-bit integer items sent or received using the Message Protocol (MP).

Exception Summary

Exception	Description
ChannelClosedException	Class ChannelClosedException is thrown to indicate that an I/O operation failed because the channel was closed.
ChannelGroupClosedException	Class ChannelGroupClosedException is thrown to indicate that an I/O operation failed because the channel group was closed.

Package edu.rit.mp Description

Package edu.rit.mp contains the Message Protocol (MP), a transport layer protocol for sending messages using TCP. MP is intended for use in message passing parallel programming on cluster parallel computers.

Operation

A source process sends a message to a destination process through a channel. Each message includes a tag; this is just an integer that the source can use to convey metadata to the destination. Each message also includes a given number of items. Each item in a message is of a given type (the same type for all items in the message). The supported types are given in the table below. The table shows the Java type used to store the item in memory, the number of bytes used to represent the item in a message, and the range of values that can be represented.

For information on how to create channels and send and receive messages, see class ChannelGroup.

Type	Stored As	# of Bytes	Range
Boolean	boolean	1	true, false
Byte	byte	1	-128 .. 127
Short	short	2	-32768 .. 32767
Integer	int	4	-2147483648 .. 2147483647
Signed 8-bit integer	int	1	-128 .. 127
Unsigned 8-bit integer	int	1	0 .. 255
Signed 16-bit integer	int	2	-32768 .. 32767
Unsigned 16-bit integer	int	2	0 .. 65535
Long	long	8	-9223372036854775808 .. 9223372036854775807
Character	char	2	'\u0000' .. '\uFFFF'
Float	float	4	Same as float
Double	double	8	Same as double
Object	Object	Varies

Message Format

A message consists of the following sequence of bytes:

• A magic number, 30144596 (an integer, four bytes, MSB first).
  
• The tag (an integer, four bytes, MSB first).
  
• The type of item (one byte).
  
• The number of items N (an integer, four bytes, MSB first).
  
• The item values, each item represented with the number of bytes given in the above table. For type = Object, the item values are represented as a sequence of bytes consisting of N objects serialized using Java Object Serialization.