All Superinterfaces:

Constructable<Message>, SizeStreamable, Streamable

All Known Implementing Classes:

BaseMessage, BatchMessage, BytesMessage, CompositeMessage, EmptyMessage, FragmentedMessage, LongMessage, NioMessage, ObjectMessage
```
public interface Message
extends SizeStreamable, Constructable<Message>
```
A Message is used to send data to members of a group. It contains the address of the sender, the destination address, (typically) a payload, flags and a list of headers.
Subclasses define different types of payloads, e.g. byte arrays, ByteBuffers, Objects etc.

Since:

5.0

Author:

Bela Ban

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class Message.Flag

static class Message.TransientFlag

Field Summary

Fields
Modifier and Type	Field	Description
`static short`	`BYTES_MSG`
`static short`	`COMPOSITE_MSG`
`static short`	`EARLYBATCH_MSG`
`static short`	`EMPTY_MSG`
`static short`	`FRAG_MSG`
`static short`	`LONG_MSG`
`static short`	`NIO_MSG`
`static short`	`OBJ_MSG`

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`Message`	`clearFlag(Message.Flag... flags)`	Removes a number of flags from the message.
`Message`	`clearFlag(Message.TransientFlag... flags)`	Removes a number of transient flags from the message.
`Message`	`clearHeaders()`	Removes all headers: use carefully!
`Message`	`copy(boolean copy_payload, boolean copy_headers)`	Copies a message
`default Address`	`dest()`
`default Message`	`dest(Address new_dest)`
`byte[]`	`getArray()`	Returns a reference to the payload (byte array).
`Address`	`getDest()`	Returns the destination address to send the message to.
`default short`	`getFlags()`
`short`	`getFlags(boolean transient_flags)`	Returns the flags as an or-ed short
`<T extends Header> T`	`getHeader(short id)`	Gets a header from the message
`java.util.Map<java.lang.Short,Header>`	`getHeaders()`	Returns a hashmap of all header IDs and their associated headers
`int`	`getLength()`	Returns the length of the byte[] array payload.
`int`	`getNumHeaders()`	Returns the number of headers
`<T> T`	`getObject()`	Gets an object from the payload.
`int`	`getOffset()`	Returns the offset of the byte[] array at which user data starts.
`<T> T`	`getPayload()`	Returns the payload without any conversion (e.g.
`Address`	`getSrc()`	Returns the address of the sender
`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`	`isFlagSet(Message.Flag flag)`	Returns true if a flag is set, false otherwise
`boolean`	`isFlagSet(Message.TransientFlag flag)`	Returns true if a transient flag is set, false otherwise
`java.lang.String`	`printHeaders()`	Returns a pretty-printed string of the headers
`Message`	`putHeader(short id, Header hdr)`	Adds a header to the message
`Message`	`putHeaderIfAbsent(short id, Header hdr)`	Adds a header to a message if not present
`void`	`readPayload(java.io.DataInput in)`
`default Message`	`setArray(byte[] b)`
`Message`	`setArray(byte[] b, int offset, int length)`	Sets the byte array in a message. Throws an exception if the message does not have a byte[] array payload (`hasArray()` is false). Note that this is a convenience method, as most messages are of type `BytesMessage`.
`Message`	`setArray(ByteArray buf)`	Sets the byte array in a message. Throws an exception if the message does not have a byte[] array payload (`hasArray()` is false). Note that this is a convenience method, as most messages are of type `BytesMessage`.
`Message`	`setDest(Address new_dest)`	Sets the destination address to send the message to.
`default Message`	`setFlag(short flag, boolean transient_flags)`	Sets the flags as a short; this way, multiple flags can be set in one operation
`Message`	`setFlag(short flag, boolean transient_flags, boolean xor)`	Sets the flags as a short; this way, multiple flags can be set in one operation
`Message`	`setFlag(Message.Flag... flags)`	Sets one or more flags (xor-ing existing flags)
`Message`	`setFlag(Message.TransientFlag... flags)`	Sets one or more transient flags (xor-ing).
`boolean`	`setFlagIfAbsent(Message.TransientFlag flag)`	Atomically sets a transient flag if not set.
`Message`	`setObject(java.lang.Object obj)`	Sets an object in a message.
`Message`	`setPayload(java.lang.Object pl)`	Sets the payload
`Message`	`setSrc(Address new_src)`	Sets the address of the sender of this message
`int`	`size()`	Returns the exact size of the marshalled message
`default Address`	`src()`
`default Message`	`src(Address new_src)`
`void`	`writePayload(java.io.DataOutput out)`
`void`	`writeToNoAddrs(Address src, java.io.DataOutput out)`	Writes the message to an output stream excluding the destination (and possibly source) address

Methods inherited from interface org.jgroups.Constructable
create

Methods inherited from interface org.jgroups.util.SizeStreamable
serializedSize

Methods inherited from interface org.jgroups.util.Streamable
readFrom, writeTo

- Field Detail
  - BYTES_MSG
```
static final short BYTES_MSG
```
    See Also:
    
    Constant Field Values
  - NIO_MSG
```
static final short NIO_MSG
```
    See Also:
    
    Constant Field Values
  - EMPTY_MSG
```
static final short EMPTY_MSG
```
    See Also:
    
    Constant Field Values
  - OBJ_MSG
```
static final short OBJ_MSG
```
    See Also:
    
    Constant Field Values
  - LONG_MSG
```
static final short LONG_MSG
```
    See Also:
    
    Constant Field Values
  - COMPOSITE_MSG
```
static final short COMPOSITE_MSG
```
    See Also:
    
    Constant Field Values
  - FRAG_MSG
```
static final short FRAG_MSG
```
    See Also:
    
    Constant Field Values
  - EARLYBATCH_MSG
```
static final short EARLYBATCH_MSG
```
    See Also:
    
    Constant Field Values
- Method Detail
  - getType
```
short getType()
```
    Returns the type of the message, e.g. BYTES_MSG, OBJ_MSG etc
  - getDest
```
Address getDest()
```
    Returns the destination address to send the message to. A null value sends the message to all cluster members
  - dest
```
default Address dest()
```
  - setDest
```
Message setDest(Address new_dest)
```
    Sets the destination address to send the message to. A null value sends the message to all cluster members
  - dest
```
default Message dest(Address new_dest)
```
  - getSrc
```
Address getSrc()
```
    Returns the address of the sender
  - src
```
default Address src()
```
  - setSrc
```
Message setSrc(Address new_src)
```
    Sets the address of the sender of this message
  - src
```
default Message src(Address new_src)
```
  - putHeader
```
Message putHeader(short id,
                  Header hdr)
```
    Adds a header to the message
  - putHeaderIfAbsent
```
Message putHeaderIfAbsent(short id,
                          Header hdr)
```
    Adds a header to a message if not present
  - getHeader
```
<T extends Header> T getHeader(short id)
```
    Gets a header from the message
  - getHeaders
```
java.util.Map<java.lang.Short,Header> getHeaders()
```
    Returns a hashmap of all header IDs and their associated headers
  - getNumHeaders
```
int getNumHeaders()
```
    Returns the number of headers
  - printHeaders
```
java.lang.String printHeaders()
```
    Returns a pretty-printed string of the headers
  - clearHeaders
```
Message clearHeaders()
```
    Removes all headers: use carefully!
  - setFlag
```
Message setFlag(Message.Flag... flags)
```
    Sets one or more flags (xor-ing existing flags)
  - setFlag
```
default Message setFlag(short flag,
                        boolean transient_flags)
```
    Sets the flags as a short; this way, multiple flags can be set in one operation
    
    Parameters:
    
    flag - The flag to be set (as a short). Overrides existing flags (no xor-ing)
    
    transient_flags - True if the flag is transient, false otherwise
  - setFlag
```
Message setFlag(short flag,
                boolean transient_flags,
                boolean xor)
```
    Sets the flags as a short; this way, multiple flags can be set in one operation
    
    Parameters:
    
    flag - The flag to be set (as a short). Overrides existing flags (no xor-ing)
    
    transient_flags - True if the flag is transient, false otherwise
    
    xor - When true, existing flags will be xor-ed with flag, otherwise not
  - setFlag
```
Message setFlag(Message.TransientFlag... flags)
```
    Sets one or more transient flags (xor-ing). Transient flags are not marshalled
  - setFlagIfAbsent
```
boolean setFlagIfAbsent(Message.TransientFlag flag)
```
    Atomically sets a transient flag if not set. Returns true if the flags was set, else false (already set)
  - getFlags
```
short getFlags(boolean transient_flags)
```
    Returns the flags as an or-ed short
    
    Parameters:
    
    transient_flags - Returns transient flags if true, else regular flags
  - getFlags
```
default short getFlags()
```
  - clearFlag
```
Message clearFlag(Message.Flag... flags)
```
    Removes a number of flags from the message. No-op for a flag if it is not set
  - clearFlag
```
Message clearFlag(Message.TransientFlag... flags)
```
    Removes a number of transient flags from the message. No-op for a flag if it is not set
  - isFlagSet
```
boolean isFlagSet(Message.Flag flag)
```
    Returns true if a flag is set, false otherwise
  - isFlagSet
```
boolean isFlagSet(Message.TransientFlag flag)
```
    Returns true if a transient flag is set, false otherwise
  - copy
```
Message copy(boolean copy_payload,
             boolean copy_headers)
```
    Copies a message
    
    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
  - hasPayload
```
boolean hasPayload()
```
    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 hasArray(), as it is not just applicable to a byte array.
    
    Returns:
    
    True if the message has a payload
  - hasArray
```
boolean hasArray()
```
    Returns true if this message has a byte[] array as payload (even if it's null!), false otherwise
  - getArray
```
byte[] getArray()
```
    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 (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.
  - getOffset
```
int getOffset()
```
    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 hasArray() is false).
    Note that this is a convenience method, as most messages are of type BytesMessage.
  - getLength
```
int getLength()
```
    Returns the length of the byte[] array payload. If the message does not have a byte[] array payload (hasArray() is false), then the serialized size may be returned, or an implementation may choose to throw an exception
  - setArray
```
Message setArray(byte[] b,
                 int offset,
                 int length)
```
    Sets the byte array in a message.
    Throws an exception if the message does not have a byte[] array payload (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
```
default Message setArray(byte[] b)
```
  - setArray
```
Message setArray(ByteArray buf)
```
    Sets the byte array in a message.
    Throws an exception if the message does not have a byte[] array payload (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.
  - getObject
```
<T> T getObject()
```
    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.
  - setObject
```
Message setObject(java.lang.Object obj)
```
    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
  - getPayload
```
<T> T getPayload()
```
    Returns the payload without any conversion (e.g. as in getObject() or getArray())
    
    Type Parameters:
    
    T - The type of the object
    
    Returns:
    
    The payload
  - setPayload
```
Message setPayload(java.lang.Object pl)
```
    Sets the payload
    
    Parameters:
    
    pl - The paylolad
  - size
```
int size()
```
    Returns the exact size of the marshalled message
    
    Returns:
    
    The number of bytes for the marshalled message
  - writeToNoAddrs
```
void writeToNoAddrs(Address src,
                    java.io.DataOutput out)
             throws java.io.IOException
```
    Writes the message to an output stream excluding the destination (and possibly source) address
    
    Throws:
    
    java.io.IOException
  - writePayload
```
void writePayload(java.io.DataOutput out)
           throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - readPayload
```
void readPayload(java.io.DataInput in)
          throws java.io.IOException,
                 java.lang.ClassNotFoundException
```
    Throws:
    
    java.io.IOException
    
    java.lang.ClassNotFoundException

Modifier and Type	Interface	Description
`static class`	`Message.Flag`
`static class`	`Message.TransientFlag`

Interface Message

Nested Class Summary

Field Summary

Method Summary

Methods inherited from interface org.jgroups.Constructable

Methods inherited from interface org.jgroups.util.SizeStreamable

Methods inherited from interface org.jgroups.util.Streamable

Field Detail

BYTES_MSG

NIO_MSG

EMPTY_MSG

OBJ_MSG

LONG_MSG

COMPOSITE_MSG

FRAG_MSG

EARLYBATCH_MSG

Method Detail

getType

getDest

dest

setDest

dest

getSrc

src

setSrc

src

putHeader

putHeaderIfAbsent

getHeader

getHeaders

getNumHeaders

printHeaders

clearHeaders

setFlag

setFlag

setFlag

setFlag

setFlagIfAbsent

getFlags

getFlags

clearFlag

clearFlag

isFlagSet

isFlagSet

copy

hasPayload

hasArray

getArray

getOffset

getLength

setArray

setArray

setArray

getObject

setObject

getPayload

setPayload

size

writeToNoAddrs

writePayload

readPayload