org.infinispan.commands.write

Class ClearCommand

java.lang.Object

org.infinispan.commands.AbstractLocalFlagAffectedCommand

org.infinispan.commands.AbstractFlagAffectedCommand

org.infinispan.commands.write.ClearCommand

All Implemented Interfaces:

FlagAffectedCommand, LocalFlagAffectedCommand, MetadataAwareCommand, ReplicableCommand, TopologyAffectedCommand, VisitableCommand, WriteCommand

public class ClearCommand
extends AbstractFlagAffectedCommand
implements WriteCommand

Since:

4.0

Author:

Mircea.Markus@jboss.com

Field Summary

Fields

Modifier and Type	Field and Description
static byte	COMMAND_ID

Fields inherited from class org.infinispan.commands.AbstractLocalFlagAffectedCommand

flags

Constructor Summary

Constructors

Constructor and Description
ClearCommand()
ClearCommand(CacheNotifier notifier, Set<Flag> flags)

Method Summary

Methods

Modifier and Type	Method and Description
Object	acceptVisitor(InvocationContext ctx, Visitor visitor) Accept a visitor, and return the result of accepting this visitor.
boolean	canBlock() If true, the command is processed asynchronously in a thread provided by an Infinispan thread pool.
Set<Object>	getAffectedKeys()
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	ignoreCommandOnStatus(ComponentStatus status) Similar to VisitableCommand.shouldInvoke(InvocationContext) but evaluated by InvocationContextInterceptor.
void	init(CacheNotifier notifier)
boolean	isConditional() Certain commands only work based on a certain condition or state of the cache.
boolean	isIgnorePreviousValue() Only relevant for conditional commands.
boolean	isReturnValueExpected() If true, a return value will be provided when performed remotely.
boolean	isSuccessful() Some commands may want to provide information on whether the command was successful or not.
Object	perform(InvocationContext ctx) Performs the primary function of the command.
void	setIgnorePreviousValue(boolean ignorePreviousValue) Only relevant for conditional commands.
void	setParameters(int commandId, Object[] parameters) Used by the CommandsFactory to create a command from raw data read off a stream.
boolean	shouldInvoke(InvocationContext ctx) Used by the InboundInvocationHandler to determine whether the command should be invoked or not.
String	toString()

Methods inherited from class org.infinispan.commands.AbstractFlagAffectedCommand

getMetadata, getTopologyId, setMetadata, setTopologyId

Methods inherited from class org.infinispan.commands.AbstractLocalFlagAffectedCommand

getFlags, hasFlag, setFlags, setFlags

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.infinispan.commands.TopologyAffectedCommand

getTopologyId, setTopologyId

Methods inherited from interface org.infinispan.commands.MetadataAwareCommand

getMetadata, setMetadata

Methods inherited from interface org.infinispan.commands.LocalFlagAffectedCommand

getFlags, hasFlag, setFlags, setFlags

Field Detail

COMMAND_ID

public static final byte COMMAND_ID

See Also:

Constant Field Values

Constructor Detail

ClearCommand

public ClearCommand()

ClearCommand

public ClearCommand(CacheNotifier notifier,
            Set<Flag> flags)

Method Detail

init

public void init(CacheNotifier notifier)

acceptVisitor

public Object acceptVisitor(InvocationContext ctx,
                   Visitor visitor)
                     throws Throwable

Description copied from interface: VisitableCommand

Accept a visitor, and return the result of accepting this visitor.

Specified by:

acceptVisitor in interface VisitableCommand

Parameters:

ctx - invocation context

visitor - visitor to accept

Returns:

arbitrary return value

Throws:

Throwable - in the event of problems

perform

public Object perform(InvocationContext ctx)
               throws Throwable

Description copied from interface: ReplicableCommand

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.

Specified by:

perform in interface ReplicableCommand

Parameters:

ctx - invocation context

Returns:

arbitrary return value generated by performing this command

Throws:

Throwable - in the event of problems.

getParameters

public Object[] getParameters()

Description copied from interface: ReplicableCommand

Used by marshallers to stream this command across a network

Specified by:

getParameters in interface ReplicableCommand

Returns:

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

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.

setParameters

public void setParameters(int commandId,
                 Object[] parameters)

Description copied from interface: ReplicableCommand

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

Specified by:

setParameters in interface ReplicableCommand

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

shouldInvoke

public boolean shouldInvoke(InvocationContext ctx)

Description copied from interface: VisitableCommand

Used by the InboundInvocationHandler to determine whether the command should be invoked or not.

Specified by:

shouldInvoke in interface VisitableCommand

Returns:

true if the command should be invoked, false otherwise.

toString

public String toString()

Overrides:

toString in class Object

isSuccessful

public boolean isSuccessful()

Description copied from interface: WriteCommand

Some commands may want to provide information on whether the command was successful or not. This is different from a failure, which usually would result in an exception being thrown. An example is a putIfAbsent() not doing anything because the key in question was present. This would result in a isSuccessful() call returning false.

Specified by:

isSuccessful in interface WriteCommand

Returns:

true if the command completed successfully, false otherwise.

isConditional

public boolean isConditional()

Description copied from interface: WriteCommand

Certain commands only work based on a certain condition or state of the cache. For example, ConcurrentMap.putIfAbsent(Object, Object) only does anything if a condition is met, i.e., the entry in question is not already present. This method tests whether the command in question is conditional or not.

Specified by:

isConditional in interface WriteCommand

Returns:

true if the command is conditional, false otherwise

isIgnorePreviousValue

public boolean isIgnorePreviousValue()

Description copied from interface: WriteCommand

Only relevant for conditional commands.

Specified by:

isIgnorePreviousValue in interface WriteCommand

Returns:

true if the command isn't really conditional, because the previous value was already checked - either on the originator (tx) or on the primary owner (non-tx).

setIgnorePreviousValue

public void setIgnorePreviousValue(boolean ignorePreviousValue)

Description copied from interface: WriteCommand

Only relevant for conditional commands.

Specified by:

setIgnorePreviousValue in interface WriteCommand

Parameters:

ignorePreviousValue - true if the command isn't really conditional, because the previous value was already checked - either on the originator (tx) or on the primary owner (non-tx).

getAffectedKeys

public Set<Object> getAffectedKeys()

Specified by:

getAffectedKeys in interface WriteCommand

Returns:

a collection of keys affected by this write command. Some commands - such as ClearCommand - may return an empty collection for this method.

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

ignoreCommandOnStatus

public boolean ignoreCommandOnStatus(ComponentStatus status)

Description copied from interface: VisitableCommand

Similar to VisitableCommand.shouldInvoke(InvocationContext) but evaluated by InvocationContextInterceptor. Commands can opt to be discarded in case the cache status is not suited (as InvalidateCommand)

Specified by:

ignoreCommandOnStatus in interface VisitableCommand

Returns:

true if the command should NOT be invoked.