org.infinispan.commands

Interface ReplicableCommand

All Known Subinterfaces:

CacheRpcCommand, CancellableCommand, DataCommand, DataWriteCommand, FlagAffectedCommand, TopologyAffectedCommand, TotalOrderPrepareCommand, TransactionBoundaryCommand, VisitableCommand, WriteCommand

All Known Implementing Classes:

AbstractDataCommand, AbstractDataWriteCommand, AbstractFlagAffectedCommand, AbstractTransactionBoundaryCommand, ApplyDeltaCommand, BaseRpcCommand, BaseRpcInvokingCommand, CacheTopologyControlCommand, CancelCommand, ClearCommand, ClusteredGetCommand, ClusteredQueryCommand, CommitCommand, CompleteTransactionCommand, CreateCacheCommand, DistributedExecuteCommand, EntrySetCommand, EvictCommand, GetInDoubtTransactionsCommand, GetInDoubtTxInfoCommand, GetKeyValueCommand, IndexUpdateCommand, InvalidateCommand, InvalidateL1Command, KeySetCommand, LockControlCommand, MapCombineCommand, MultipleRpcCommand, PrepareCommand, PutKeyValueCommand, PutMapCommand, RecoveryCommand, ReduceCommand, RemoveCacheCommand, RemoveCommand, ReplaceCommand, RollbackCommand, SingleRpcCommand, SizeCommand, StateRequestCommand, StateResponseCommand, TotalOrderCommitCommand, TotalOrderNonVersionedPrepareCommand, TotalOrderRollbackCommand, TotalOrderVersionedCommitCommand, TotalOrderVersionedPrepareCommand, TxCompletionNotificationCommand, ValuesCommand, VersionedCommitCommand, VersionedPrepareCommand, XSiteAdminCommand

public interface ReplicableCommand

The core of the command-based cache framework. Commands correspond to specific areas of functionality in the cache, and can be replicated using the RpcManager

Since:

4.0

Author:

Mircea.Markus@jboss.com, Manik Surtani

Method Summary

Methods

Modifier and Type	Method and 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.
Object[]	getParameters() Used by marshallers to stream this command across a network
boolean	isReturnValueExpected() If true, a return value will be provided when performed remotely.
Object	perform(InvocationContext ctx) Performs the primary function of the command.
void	setParameters(int commandId, Object[] parameters) Used by the CommandsFactory to create a command from raw data read off a stream.

Method Detail

perform

Object perform(InvocationContext ctx)
               throws Throwable

Performs the primary function of the command. Please see specific implementation classes for details on what is performed as well as return types. Important: this method will be invoked at the end of interceptors chain. It should never be called directly from a custom interceptor.

Parameters:

ctx - invocation context

Returns:

arbitrary return value generated by performing this command

Throws:

Throwable - in the event of problems.

getCommandId

byte getCommandId()

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

Returns:

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

getParameters

Object[] getParameters()

Used by marshallers to stream this command across a network

Returns:

an object array of arguments, compatible with pre-2.2.0 MethodCall args.

setParameters

void setParameters(int commandId,
                 Object[] parameters)

Used by the CommandsFactory to create a command from raw data read off a stream.

Parameters:

commandId - command id to set. This is usually unused but *could* be used in the event of a command having multiple IDs, such as PutKeyValueCommand.

parameters - object array of args

isReturnValueExpected

boolean isReturnValueExpected()

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.

Returns:

true or false

canBlock

boolean canBlock()

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.

Returns:

true if the command can block/wait, false otherwise