Package org.jgroups

Class CompositeMessage

java.lang.Object

org.jgroups.BaseMessage

org.jgroups.CompositeMessage

All Implemented Interfaces:

java.lang.Iterable<Message>, Constructable<Message>, Message, SizeStreamable, Streamable

public class CompositeMessage
extends BaseMessage
implements java.lang.Iterable<Message>

A message composed of multiple messages. This is useful when multiple messages are to be passed in a single message. Example: a byte buffer (1000 bytes) with a request type (req/rsp/ack).
In versions prior to 5.0, the byte arrays had to be copied into a single, larger (1001 bytes), byte array in order to be passed to the message.
This class is unsynchronized; the envisaged use case is that a CompositeMessage is created with a number of messages, or messages are added, but then the instance is not modified anymore and sent.

Since:

5.0

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	CompositeMessage.CompositeMessageIterator

Nested classes/interfaces inherited from interface org.jgroups.Message

Message.Flag, Message.TransientFlag

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	collapse
protected int	index
protected static MessageFactory	mf
protected Message[]	msgs

Fields inherited from class org.jgroups.BaseMessage

dest, flags, headers, sender, transient_flags

Fields inherited from interface org.jgroups.Message

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

Constructor Summary

Constructors

Constructor	Description
CompositeMessage()
CompositeMessage(Address dest)
CompositeMessage(Address dest, Message... messages)

Method Summary

Modifier and Type	Method	Description
CompositeMessage	add(Message msg)	Adds the message at the end of the array.
CompositeMessage	add(Message... messages)
boolean	collapse()
CompositeMessage	collapse(boolean b)
CompositeMessage	copy(boolean copy_payload, boolean copy_headers)	Create a copy of this CompositeMessage.
java.util.function.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.
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.
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.
java.util.Iterator<Message>	iterator()
void	readPayload(java.io.DataInput in)
CompositeMessage	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.
CompositeMessage	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.
CompositeMessage	setObject(java.lang.Object obj)	Sets an object in a message.
int	size()	Returns the exact size of the marshalled message
java.lang.String	toString()
void	writePayload(java.io.DataOutput out)
protected void	writePayloadAsBytes(java.io.DataOutput out)

Methods inherited from class org.jgroups.BaseMessage

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.jgroups.Message

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

Field Detail

msgs

protected Message[] msgs

index

protected int index

collapse

protected boolean collapse

mf

protected static final MessageFactory mf

Constructor Detail

CompositeMessage

public CompositeMessage()

CompositeMessage

public CompositeMessage(Address dest)

CompositeMessage

public CompositeMessage(Address dest,
                        Message... messages)

Method Detail

create

public java.util.function.Supplier<Message> create()

Description copied from interface: Constructable

Creates an instance of the class implementing this interface

Specified by:

create in interface Constructable<Message>

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 CompositeMessage 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 CompositeMessage 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 CompositeMessage setObject(java.lang.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

collapse

public boolean collapse()

collapse

public CompositeMessage collapse(boolean b)

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 CompositeMessage add(Message msg)

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

add

public CompositeMessage add(Message... messages)

get

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

copy

public CompositeMessage copy(boolean copy_payload,
                             boolean copy_headers)

Create a copy of this CompositeMessage.

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 java.lang.String toString()

Overrides:

toString in class BaseMessage

size

public int size()

Description copied from interface: Message

Returns the exact size of the marshalled message

Specified by:

size in interface Message

Overrides:

size in class BaseMessage

Returns:

The number of bytes for the marshalled message

iterator

public java.util.Iterator<Message> iterator()

Specified by:

iterator in interface java.lang.Iterable<Message>

writePayload

public void writePayload(java.io.DataOutput out)
                  throws java.io.IOException

Specified by:

writePayload in interface Message

Throws:

java.io.IOException

readPayload

public void readPayload(java.io.DataInput in)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException

Specified by:

readPayload in interface Message

Throws:

java.io.IOException

java.lang.ClassNotFoundException

writePayloadAsBytes

protected void writePayloadAsBytes(java.io.DataOutput out)
                            throws java.io.IOException

Throws:

java.io.IOException

ensureCapacity

protected void ensureCapacity(int size)

ensureSameDest

protected Message ensureSameDest(Message msg)