public class STREAMING_STATE_TRANSFER extends Protocol
STREAMING_STATE_TRANSFER
, as its name implies, allows a
streaming state transfer between two channel instances.
Major advantage of this approach is that transferring application state to a
joining member of a group does not entail loading of the complete application
state into memory. Application state, for example, might be located entirely
on some form of disk based storage. The default STATE_TRANSFER
requires this state to be loaded entirely into memory before being
transferred to a group member while STREAMING_STATE_TRANSFER
does not. Thus STREAMING_STATE_TRANSFER
protocol is able to
transfer application state that is very large (>1Gb) without a likelihood of
such transfer resulting in OutOfMemoryException.
Channel instance can be configured with either
In order to process streaming state transfer an application has to implement
STREAMING_STATE_TRANSFER
allows use of either default channel
transport or separate tcp sockets for state transfer. If firewalls are not a
concern then separate tcp sockets should be used as they offer faster state
transfer. Transport for state transfer is selected using
use_default_transport
boolean property.
STREAMING_STATE_TRANSFER
or STATE_TRANSFER
but not
both protocols at the same time.
ExtendedMessageListener
if it is using channel in a push style
mode or it has to process StreamingSetStateEvent
and
StreamingGetStateEvent
if it is using channel in a pull style
mode.
ExtendedMessageListener
,
StreamingGetStateEvent
,
StreamingSetStateEvent
,
STATE_TRANSFER
Modifier and Type | Class and Description |
---|---|
static class |
STREAMING_STATE_TRANSFER.StateHeader |
Modifier and Type | Field and Description |
---|---|
protected String |
bind_interface_str |
Constructor and Description |
---|
STREAMING_STATE_TRANSFER() |
Modifier and Type | Method and Description |
---|---|
Object |
down(Event evt)
An event is to be sent down the stack.
|
double |
getAverageStateSize() |
long |
getNumberOfStateBytesSent() |
int |
getNumberOfStateRequests() |
void |
init()
Called after instance has been created (null constructor) and before protocol is started.
|
Vector<Integer> |
requiredDownServices()
List of events that are required to be answered by some layer below.
|
void |
resetStats() |
void |
start()
This method is called on a
Channel.connect(String) . |
void |
stop()
This method is called on a
Channel.disconnect() . |
Object |
up(Event evt)
An event was received from the layer below.
|
destroy, downThreadEnabled, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getId, getLevel, getName, getProperties, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getValue, isErgonomics, printStats, providedDownServices, providedUpServices, requiredUpServices, setDownProtocol, setErgonomics, setId, setLevel, setProperties, setPropertiesInternal, setProperty, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled, upThreadEnabled
protected String bind_interface_str
public int getNumberOfStateRequests()
public long getNumberOfStateBytesSent()
public double getAverageStateSize()
public Vector<Integer> requiredDownServices()
Protocol
requiredDownServices
in class Protocol
public void resetStats()
resetStats
in class Protocol
public void init() throws Exception
Protocol
public void start() throws Exception
Protocol
Channel.connect(String)
. Starts work.
Protocols are connected and queues are ready to receive events.
Will be called from bottom to top. This call will replace
the START and START_OK events.start
in class Protocol
Exception
- Thrown if protocol cannot be started successfully. This will cause the ProtocolStack
to fail, so Channel.connect(String)
will throw an exceptionpublic void stop()
Protocol
Channel.disconnect()
. Stops work (e.g. by closing multicast socket).
Will be called from top to bottom. This means that at the time of the method invocation the
neighbor protocol below is still working. This method will replace the
STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that
when this method is called all messages in the down queue will have been flushedpublic Object up(Event evt)
Protocol
down_prot.down()
or c) the event (or another event) is sent up
the stack using up_prot.up()
.public Object down(Event evt)
Protocol
down_prot.down()
. In case of a GET_ADDRESS event (which tries to
retrieve the stack's address from one of the bottom layers), the layer may need to send
a new response event back up the stack using up_prot.up()
.Copyright © 2013 JBoss, a division of Red Hat. All Rights Reserved.