Package org.infinispan.topology

Class HeartBeatCommand

java.lang.Object

org.infinispan.topology.HeartBeatCommand

All Implemented Interfaces:

ReplicableCommand

public class HeartBeatCommand
extends Object
implements ReplicableCommand

A hear-beat command used to ping members in ClusterTopologyManagerImpl.confirmMembersAvailable().

Since:

9.2

Author:

Pedro Ruivo

Field Summary

Fields

Modifier and Type	Field	Description
static byte	COMMAND_ID
static HeartBeatCommand	INSTANCE

Constructor Summary

Constructors

Constructor	Description
HeartBeatCommand()

Method Summary

Modifier and Type	Method	Description
boolean	canBlock()	If true, the command is processed asynchronously in a thread provided by an Infinispan thread pool.
byte	getCommandId()	Used by marshallers to convert this command into an id for streaming.
boolean	isReturnValueExpected()	If true, a return value will be provided when performed remotely.
void	readFrom(ObjectInput input)	Reads this instance from the stream written by ReplicableCommand.writeTo(ObjectOutput).
void	writeTo(ObjectOutput output)	Writes this instance to the ObjectOutput.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.infinispan.commands.ReplicableCommand

invoke, invokeAsync, isSuccessful, perform, setOrigin

Field Detail

COMMAND_ID

public static final byte COMMAND_ID

See Also:

Constant Field Values

INSTANCE

public static final HeartBeatCommand INSTANCE

Constructor Detail

HeartBeatCommand

public HeartBeatCommand()

Method Detail

getCommandId

public byte getCommandId()

Description copied from interface: ReplicableCommand

Used by marshallers to convert this command into an id for streaming.

Specified by:

getCommandId in interface ReplicableCommand

Returns:

the method id of this command. This is compatible with pre-2.2.0 MethodCall ids.

isReturnValueExpected

public boolean isReturnValueExpected()

Description copied from interface: ReplicableCommand

If true, a return value will be provided when performed remotely. Otherwise, a remote ResponseGenerator may choose to simply return null to save on marshalling costs.

Specified by:

isReturnValueExpected in interface ReplicableCommand

Returns:

true or false

canBlock

public boolean canBlock()

Description copied from interface: ReplicableCommand

If true, the command is processed asynchronously in a thread provided by an Infinispan thread pool. Otherwise, the command is processed directly in the JGroups thread.

This feature allows to avoid keep a JGroups thread busy that can originate discard of messages and retransmissions. So, the commands that can block (waiting for some state, acquiring locks, etc.) should return true.

Specified by:

canBlock in interface ReplicableCommand

Returns:

true if the command can block/wait, false otherwise

writeTo

public void writeTo(ObjectOutput output)

Description copied from interface: ReplicableCommand

Writes this instance to the ObjectOutput.

Specified by:

writeTo in interface ReplicableCommand

Parameters:

output - the stream.

readFrom

public void readFrom(ObjectInput input)

Description copied from interface: ReplicableCommand

Reads this instance from the stream written by ReplicableCommand.writeTo(ObjectOutput).

Specified by:

readFrom in interface ReplicableCommand

Parameters:

input - the stream to read.