io.permazen.kv.raft.msg

Class Message

java.lang.Object

io.permazen.kv.raft.msg.Message

Direct Known Subclasses:

AppendRequest, AppendResponse, CommitRequest, CommitResponse, GrantVote, InstallSnapshot, PingRequest, PingResponse, RequestVote

public abstract class Message
extends Object

Support superclass for Raft messages.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Message(byte type, ByteBuffer buf, int version)
protected	Message(byte type, int clusterId, String senderId, String recipientId, long term)

Method Summary

Modifier and Type	Method and Description
protected static int	calculateSize(ByteBuffer buf)
protected int	calculateSize(int version) Calculate an upper bound on the number of bytes required by writeTo().
protected static int	calculateSize(String string)
protected static int	calculateSize(Timestamp timestamp, int version)
static Message	decode(ByteBuffer buf, int version) Decode a message from the given input.
static int	decodeProtocolVersion(ByteBuffer buf) Read the protocol version number header from the message encoded in the given input.
ByteBuffer	encode(int version) Serialize this instance.
protected static boolean	getBoolean(ByteBuffer buf) Deserialize a boolean value previously serialized by putBoolean() from the buffer.
protected static ByteBuffer	getByteBuffer(ByteBuffer buf) Deserialize a ByteBuffer previously serialized by putByteBuffer() from the buffer.
int	getClusterId() Get the cluster ID of the sender.
static int	getCurrentProtocolVersion() Get the current (i.e., maximum known) protocol version number.
String	getRecipientId() Get the identity of the recipient.
String	getSenderId() Get the identity of the sender.
protected static String	getString(ByteBuffer buf) Deserialize a String previously serialized by putString() from the buffer.
long	getTerm() Get the term of the sender of this message.
protected static Timestamp	getTimestamp(ByteBuffer buf, int version) Deserialize a Timestamp value previously serialized by putTimestamp() from the buffer.
boolean	isLeaderMessage() Determine whether this message is only sent by leaders.
protected static void	putBoolean(ByteBuffer dest, boolean value) Serialize a boolean value into the buffer.
protected static void	putByteBuffer(ByteBuffer dest, ByteBuffer buf) Serialize a ByteBuffer into the buffer.
protected static void	putString(ByteBuffer dest, String string) Serialize a String into the buffer.
protected static void	putTimestamp(ByteBuffer dest, Timestamp timestamp, int version) Serialize a Timestamp value into the buffer.
abstract String	toString()
abstract void	visit(MessageSwitch handler) Apply the visitor pattern based on this instance's type.
void	writeTo(ByteBuffer buf, int version) Serialize this instance into the given buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

Message

protected Message(byte type,
                  int clusterId,
                  String senderId,
                  String recipientId,
                  long term)

Message

protected Message(byte type,
                  ByteBuffer buf,
                  int version)

Method Detail

getClusterId

public int getClusterId()

Get the cluster ID of the sender.

Returns:

sender's cluster ID

getSenderId

public String getSenderId()

Get the identity of the sender.

Returns:

sender's unique identity string

getRecipientId

public String getRecipientId()

Get the identity of the recipient.

Returns:

recipient's unique identity string

getTerm

public long getTerm()

Get the term of the sender of this message.

Returns:

requester's unique ID

isLeaderMessage

public boolean isLeaderMessage()

Determine whether this message is only sent by leaders.

Returns:

true if receipt of this message implies sender is a leader

visit

public abstract void visit(MessageSwitch handler)

Apply the visitor pattern based on this instance's type.

Parameters:

handler - target for visit

getCurrentProtocolVersion

public static int getCurrentProtocolVersion()

Get the current (i.e., maximum known) protocol version number.

Returns:

latest message protocol version

decodeProtocolVersion

public static int decodeProtocolVersion(ByteBuffer buf)

Read the protocol version number header from the message encoded in the given input.

Parameters:

buf - source for encoded message

Returns:

decoded message protocol version

decode

public static Message decode(ByteBuffer buf,
                             int version)

Decode a message from the given input. The protocol version number header should already have been read.

Note that data is not necessarily copied out of buf, so the returned instance may become invalid if the data in buf gets overwritten.

Parameters:

buf - source for encoded message

version - message version

Returns:

decoded message

Throws:

BufferUnderflowException - if there is not enough data

IllegalArgumentException - if version is bogus

IllegalArgumentException - if encoded message is bogus

IllegalArgumentException - if there is trailing garbage

encode

public ByteBuffer encode(int version)

Serialize this instance.

Parameters:

version - protocol encoding version number

Returns:

encoded message

Throws:

IllegalArgumentException - if version is bogus

writeTo

public void writeTo(ByteBuffer buf,
                    int version)

Serialize this instance into the given buffer.

Parameters:

buf - destination for encoded data

version - protocol encoding version number

Throws:

BufferOverflowException - if data overflows buf

IllegalArgumentException - if version is bogus

calculateSize

protected int calculateSize(int version)

Calculate an upper bound on the number of bytes required by writeTo().

Parameters:

version - protocol encoding version

Returns:

an upper bound on the number of encoded bytes

toString

public abstract String toString()

Overrides:

toString in class Object

putByteBuffer

protected static void putByteBuffer(ByteBuffer dest,
                                    ByteBuffer buf)

Serialize a ByteBuffer into the buffer.

Parameters:

dest - destination for encoded data

buf - data to encode

Throws:

ReadOnlyBufferException - if dest is read only

BufferOverflowException - if dest overflows

IllegalArgumentException - if buf has more than 2^{^31} bytes remaining

IllegalArgumentException - if either parameter is null

getByteBuffer

protected static ByteBuffer getByteBuffer(ByteBuffer buf)

Deserialize a ByteBuffer previously serialized by putByteBuffer() from the buffer.

Parameters:

buf - source for encoded data

Returns:

decoded data

Throws:

BufferUnderflowException - if buf underflows

IllegalArgumentException - if input is bogus

IllegalArgumentException - if buf is null

calculateSize

protected static int calculateSize(ByteBuffer buf)

putString

protected static void putString(ByteBuffer dest,
                                String string)

Serialize a String into the buffer.

Parameters:

dest - destination for encoded data

string - string to encode

Throws:

ReadOnlyBufferException - if dest is read only

BufferOverflowException - if dest overflows

IllegalArgumentException - if either parameter is null

getString

protected static String getString(ByteBuffer buf)

Deserialize a String previously serialized by putString() from the buffer.

Parameters:

buf - source for encoded data

Returns:

decoded string, never null

Throws:

BufferUnderflowException - if buf underflows

IllegalArgumentException - if input is bogus

calculateSize

protected static int calculateSize(String string)

putBoolean

protected static void putBoolean(ByteBuffer dest,
                                 boolean value)

Serialize a boolean value into the buffer.

Parameters:

dest - destination for encoded data

value - value to encode

Throws:

ReadOnlyBufferException - if dest is read only

BufferOverflowException - if dest overflows

IllegalArgumentException - if dest is null

getBoolean

protected static boolean getBoolean(ByteBuffer buf)

Deserialize a boolean value previously serialized by putBoolean() from the buffer.

Parameters:

buf - source for encoded data

Returns:

decoded value

Throws:

BufferUnderflowException - if buf underflows

IllegalArgumentException - if input is bogus

putTimestamp

protected static void putTimestamp(ByteBuffer dest,
                                   Timestamp timestamp,
                                   int version)

Serialize a Timestamp value into the buffer.

Parameters:

dest - destination for encoded data

timestamp - value to encode

version - protocol encoding version

Throws:

ReadOnlyBufferException - if dest is read only

BufferOverflowException - if dest overflows

IllegalArgumentException - if dest or timestamp is null

getTimestamp

protected static Timestamp getTimestamp(ByteBuffer buf,
                                        int version)

Deserialize a Timestamp value previously serialized by putTimestamp() from the buffer.

Parameters:

buf - source for encoded data

version - protocol encoding version

Returns:

decoded value

Throws:

BufferUnderflowException - if buf underflows

IllegalArgumentException - if input is bogus

calculateSize

protected static int calculateSize(Timestamp timestamp,
                                   int version)