Class ObjectMessage

java.lang.Object

org.jgroups.BaseMessage

org.jgroups.ObjectMessage

All Implemented Interfaces:

Constructable<Message>, Message, SizeStreamable, Streamable

public class ObjectMessage
extends BaseMessage

A Message with an object as payload. The object won't get serialized until sent by the transport.
Note that the object passed to the constructor (or set with setObject(Object)) must not be changed after the creation of an ObjectMessage.

Since:

5.0

Author:

Bela Ban

Nested Class Summary

Nested classes/interfaces inherited from interface Message

Message.Flag, Message.TransientFlag

Field Summary

Fields

Modifier and Type	Field	Description
protected SizeStreamable	obj

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
ObjectMessage()
ObjectMessage(Address dest)	Constructs a message given a destination address
ObjectMessage(Address dest, Object obj)	Constructs a message given a destination address and the payload object
ObjectMessage(Address dest, SizeStreamable obj)	Constructs a message given a destination address and the payload object

Method Summary

Modifier and Type	Method	Description
protected Message	copyPayload(Message copy)	Copies the payload
Supplier<Message>	create()	Creates an instance of the class implementing this interface
byte[]	getArray()	Returns a reference to the payload (byte array).
int	getLength()	Returns the length of the byte[] array payload.
<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.
boolean	isWrapped()
protected int	payloadSize()
void	readPayload(DataInput in)
ObjectMessage	setArray(byte[] b, int off, int len)	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.
ObjectMessage	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.
ObjectMessage	setObject(Object obj)	Sets the object.
ObjectMessage	setObject(SizeStreamable obj)	Sets the payload to a SizeStreamable (or null).
ObjectMessage	setSizeStreamable(SizeStreamable s)
ObjectMessage	setWrapped(boolean b)
String	toString()
void	writePayload(DataOutput out)

Methods inherited from class BaseMessage

clearFlag, clearFlag, clearHeaders, copy, 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 Message

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

Field Details

obj

protected SizeStreamable obj

Constructor Details

ObjectMessage

public ObjectMessage()

ObjectMessage

public ObjectMessage(Address dest)

Constructs a message given a destination address

Parameters:

dest - The Address of the receiver. If it is null, then the message is sent to the group. Otherwise, it is sent to a single member.

ObjectMessage

public ObjectMessage(Address dest,
 Object obj)

Constructs a message given a destination address and the payload object

Parameters:

dest - The Address of the receiver. If it is null, then the message is sent to the group. Otherwise, it is sent to a single member.

obj - To be used as payload.

ObjectMessage

public ObjectMessage(Address dest,
 SizeStreamable obj)

Constructs a message given a destination address and the payload object

Parameters:

dest - The Address of the receiver. If it is null, then the message is sent to the group. Otherwise, it is sent to a single member.

obj - The SizeStreamable object to be used as payload. Note that this constructor has fewer checks (e.g. instanceof) than ObjectMessage(org.jgroups.Address,java.lang.Object).

Method Details

create

public Supplier<Message> create()

Description copied from interface: Constructable

Creates an instance of the class implementing this interface

Returns:

Supplier

getType

public short getType()

Description copied from interface: Message

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

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.

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

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.

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

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.

setArray

public ObjectMessage setArray(byte[] b,
 int off,
 int len)

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.

setArray

public ObjectMessage 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.

isWrapped

public boolean isWrapped()

setWrapped

public ObjectMessage setWrapped(boolean b)

setObject

public ObjectMessage setObject(Object obj)

Sets the object. If the object doesn't implement SizeStreamable, or is a primitive type, it will be wrapped into an ObjectWrapperSerializable (which does implement SizeStreamable)

setObject

public ObjectMessage setObject(SizeStreamable obj)

Sets the payload to a SizeStreamable (or null). This method has fewer checks (e.g. instanceof) than setObject(Object).

Parameters:

obj - The SizeStreamable to be used as payload (or null)

setSizeStreamable

public ObjectMessage setSizeStreamable(SizeStreamable s)

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.

writePayload

public void writePayload(DataOutput out)
                  throws IOException

Throws:

IOException

readPayload

public void readPayload(DataInput in)
                 throws IOException,
ClassNotFoundException

Throws:

IOException

ClassNotFoundException

copyPayload

protected Message copyPayload(Message copy)

Description copied from class: BaseMessage

Copies the payload

Overrides:

copyPayload in class BaseMessage

toString

public String toString()

Overrides:

toString in class BaseMessage

payloadSize

protected int payloadSize()

Specified by:

payloadSize in class BaseMessage