Class BatchMessage

java.lang.Object

org.jgroups.BaseMessage

org.jgroups.BatchMessage

All Implemented Interfaces:

Iterable<Message>, Constructable<Message>, Message, SizeStreamable, Streamable

public class BatchMessage
extends BaseMessage
implements Iterable<Message>

A message that contains a batch of messages. This message will wrap several messages, so lower protocol layers only have to process them once. This increases throughput for cases such as when average message size is small, or there is a heavy processing cost (e.g. SEQUENCER).
Similar to CompositeMessage but with some optimizations made for the specific use case.
This class is unsynchronized; the envisaged use case is that a BatchMessage is created with a number of messages, or messages are added, but then the instance is not modified anymore and sent.

Since:

5.x

Author:

Bela Ban, Chris Johnson

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	BatchMessage.BatchMessageIterator

Nested classes/interfaces inherited from interface Message

Message.Flag, Message.TransientFlag

Field Summary

Fields

Modifier and Type	Field	Description
protected int	index
protected Message[]	msgs
protected Address	orig_src

Fields inherited from class BaseMessage

dest, flags, headers, sender, transient_flags

Fields inherited from interface Message

BYTES_MSG, COMPOSITE_MSG, EARLYBATCH_MSG, EMPTY_MSG, FRAG_MSG, LONG_MSG, NIO_MSG, OBJ_MSG

Constructor Summary

Constructors

Constructor	Description
BatchMessage()
BatchMessage(Address dest, int capacity)
BatchMessage(Address dest, Address src, Message[] msgs, int index)

Method Summary

Modifier and Type	Method	Description
BatchMessage	add(Message msg)	Adds the message at the end of the array.
BatchMessage	add(Message... messages)
BatchMessage	copy(boolean copy_payload, boolean copy_headers)	Create a shallow copy of this BatchMessage.
Supplier<Message>	create()	Creates an instance of the class implementing this interface
protected void	ensureCapacity(int size)
protected Message	ensureSameDest(Message msg)
<T extends Message> T	get(int index)
byte[]	getArray()	Returns a reference to the payload (byte array).
int	getLength()	Returns the length of the byte[] array payload.
Message[]	getMessages()
int	getNumberOfMessages()
<T> T	getObject()	Gets an object from the payload.
int	getOffset()	Returns the offset of the byte[] array at which user data starts.
Address	getOrigSender()
short	getType()	Returns the type of the message, e.g.
boolean	hasArray()	Returns true if this message has a byte[] array as payload (even if it's null!), false otherwise
boolean	hasPayload()	Returns true if the message has a payload, e.g.
Iterator<Message>	iterator()
protected int	payloadSize()
void	readPayload(DataInput in)
BatchMessage	setArray(byte[] b, int o, int l)	Sets the byte array in a message. Throws an exception if the message does not have a byte[] array payload (Message.hasArray() is false). Note that this is a convenience method, as most messages are of type BytesMessage.
BatchMessage	setArray(ByteArray buf)	Sets the byte array in a message. Throws an exception if the message does not have a byte[] array payload (Message.hasArray() is false). Note that this is a convenience method, as most messages are of type BytesMessage.
BatchMessage	setObject(Object obj)	Sets an object in a message.
BatchMessage	setOrigSender(Address s)
String	toString()
void	writePayload(DataOutput out)

Methods inherited from class BaseMessage

clearFlag, clearFlag, clearHeaders, copyPayload, createHeaders, getDest, getFlags, getHeader, getHeaders, getNumHeaders, getPayload, getSrc, headers, headers, isFlagSet, isFlagSet, printHeaders, putHeader, putHeader, putHeaderIfAbsent, readFrom, serializedSize, setDest, setFlag, setFlag, setFlag, setFlagIfAbsent, setPayload, setSrc, size, sizeNoAddrs, writeTo, writeToNoAddrs

Methods inherited from class Object

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

Methods inherited from interface Iterable

forEach, spliterator

Methods inherited from interface Message

dest, dest, getFlags, length, setArray, setFlag, src, src

Field Details

msgs

protected Message[] msgs

index

protected int index

orig_src

protected Address orig_src

Constructor Details

BatchMessage

public BatchMessage()

BatchMessage

public BatchMessage(Address dest,
 int capacity)

BatchMessage

public BatchMessage(Address dest,
 Address src,
 Message[] msgs,
 int index)

Method Details

create

public Supplier<Message> create()

Description copied from interface: Constructable

Creates an instance of the class implementing this interface

Specified by:

create in interface Constructable<Message>

Returns:

Supplier

getType

public short getType()

Description copied from interface: Message

Returns the type of the message, e.g. BYTES_MSG, OBJ_MSG etc

Specified by:

getType in interface Message

hasPayload

public boolean hasPayload()

Description copied from interface: Message

Returns true if the message has a payload, e.g. a byte[] array in a BytesMessage or an object in an ObjectMessage. This is more generic than Message.hasArray(), as it is not just applicable to a byte array.

Specified by:

hasPayload in interface Message

Returns:

True if the message has a payload

hasArray

public boolean hasArray()

Description copied from interface: Message

Returns true if this message has a byte[] array as payload (even if it's null!), false otherwise

Specified by:

hasArray in interface Message

getNumberOfMessages

public int getNumberOfMessages()

getOffset

public int getOffset()

Description copied from interface: Message

Returns the offset of the byte[] array at which user data starts. Throws an exception if the message does not have a byte[] array payload (if Message.hasArray() is false).
Note that this is a convenience method, as most messages are of type BytesMessage.

Specified by:

getOffset in interface Message

getArray

public byte[] getArray()

Description copied from interface: Message

Returns a reference to the payload (byte array). Note that this array should not be modified as we do not copy the array on copy() or clone(): the array of the copied message is simply a reference to the old array.
Even if offset and length are used: we return the entire array, not a subset.
Throws an exception if the message does not have a byte[] array payload (Message.hasArray() is false).
Note that this is a convenience method, as most messages are of type BytesMessage. It is recommended to downcast a Message to the correct subtype and use the methods available there to get/set the payload.

Specified by:

getArray in interface Message

setArray

public BatchMessage setArray(byte[] b,
 int o,
 int l)

Description copied from interface: Message

Sets the byte array in a message.
Throws an exception if the message does not have a byte[] array payload (Message.hasArray() is false).
Note that this is a convenience method, as most messages are of type BytesMessage. It is recommended to downcast a Message to the correct subtype and use the methods available there to get/set the payload.

Specified by:

setArray in interface Message

setArray

public BatchMessage setArray(ByteArray buf)

Description copied from interface: Message

Sets the byte array in a message.
Throws an exception if the message does not have a byte[] array payload (Message.hasArray() is false).
Note that this is a convenience method, as most messages are of type BytesMessage. It is recommended to downcast a Message to the correct subtype and use the methods available there to get/set the payload.

Specified by:

setArray in interface Message

setObject

public BatchMessage setObject(Object obj)

Description copied from interface: Message

Sets an object in a message. In a ObjectMessage, the object is set directly. In a BytesMessage, the object is serialized into a byte[] array and then the array is set as the payload of the message

Specified by:

setObject in interface Message

getObject

public <T> T getObject()

Description copied from interface: Message

Gets an object from the payload. If the payload is a byte[] array (e.g. as in BytesMessage), an attempt to de-serialize the array into an object is made, and the object returned.
If the payload is an object (e.g. as is the case in ObjectMessage), the object will be returned directly.

Specified by:

getObject in interface Message

getMessages

public Message[] getMessages()

getOrigSender

public Address getOrigSender()

setOrigSender

public BatchMessage setOrigSender(Address s)

getLength

public int getLength()

Description copied from interface: Message

Returns the length of the byte[] array payload. If the message does not have a byte[] array payload (Message.hasArray() is false), then the serialized size may be returned, or an implementation may choose to throw an exception

Specified by:

getLength in interface Message

add

public BatchMessage add(Message msg)

Adds the message at the end of the array. Increases the array if needed

add

public BatchMessage add(Message... messages)

get

public <T extends Message> T get(int index)

copy

public BatchMessage copy(boolean copy_payload,
 boolean copy_headers)

Create a shallow copy of this BatchMessage.

Specified by:

copy in interface Message

Overrides:

copy in class BaseMessage

Parameters:

copy_payload - If true, the payload is copied, else it is null in the copied message

copy_headers - If true, the headers are copied

toString

public String toString()

Overrides:

toString in class BaseMessage

payloadSize

protected int payloadSize()

Specified by:

payloadSize in class BaseMessage

iterator

public Iterator<Message> iterator()

Specified by:

iterator in interface Iterable<Message>

writePayload

public void writePayload(DataOutput out)
                  throws IOException

Specified by:

writePayload in interface Message

Throws:

IOException

readPayload

public void readPayload(DataInput in)
                 throws IOException,
ClassNotFoundException

Specified by:

readPayload in interface Message

Throws:

IOException

ClassNotFoundException

ensureCapacity

protected void ensureCapacity(int size)

ensureSameDest

protected Message ensureSameDest(Message msg)