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<Object,Object> notifier, DataContainer<?,?> dataContainer, Set<Flag> flags)

Method Summary

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.
ValueMatcher	getValueMatcher()
boolean	ignoreCommandOnStatus(ComponentStatus status) Similar to VisitableCommand.shouldInvoke(InvocationContext) but evaluated by InvocationContextInterceptor.
void	init(CacheNotifier<Object,Object> notifier, DataContainer<?,?> dataContainer)
boolean	isConditional() Certain commands only work based on a certain condition or state of the cache.
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	readFrom(ObjectInput input) Reads this instance from the stream written by ReplicableCommand.writeTo(ObjectOutput).
boolean	readsExistingValues()
void	setValueMatcher(ValueMatcher valueMatcher)
boolean	shouldInvoke(InvocationContext ctx) Used by the InboundInvocationHandler to determine whether the command should be invoked or not.
String	toString()
void	updateStatusFromRemoteResponse(Object remoteResponse) Used for conditional commands, to update the status of the command on the originator based on the result of its execution on the primary owner.
void	writeTo(ObjectOutput output) Writes this instance to the ObjectOutput.

Methods inherited from class org.infinispan.commands.AbstractFlagAffectedCommand

getMetadata, getTopologyId, setMetadata, setTopologyId

Methods inherited from class org.infinispan.commands.AbstractLocalFlagAffectedCommand

getFlags, 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.write.WriteCommand

isWriteOnly

Methods inherited from interface org.infinispan.commands.VisitableCommand

alwaysReadsExistingValues

Methods inherited from interface org.infinispan.commands.TopologyAffectedCommand

getTopologyId, setTopologyId

Methods inherited from interface org.infinispan.commands.ReplicableCommand

getParameters, setParameters

Methods inherited from interface org.infinispan.commands.MetadataAwareCommand

getMetadata, setMetadata

Methods inherited from interface org.infinispan.commands.LocalFlagAffectedCommand

addFlag, addFlags, 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<Object,Object> notifier,
                    DataContainer<?,?> dataContainer,
                    Set<Flag> flags)

Method Detail

init

public void init(CacheNotifier<Object,Object> notifier,
                 DataContainer<?,?> dataContainer)

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.

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.

writeTo

public void writeTo(ObjectOutput output)
             throws IOException

Description copied from interface: ReplicableCommand

Writes this instance to the ObjectOutput.

Specified by:

writeTo in interface ReplicableCommand

Parameters:

output - the stream.

Throws:

IOException - if an error occurred during the I/O.

readFrom

public void readFrom(ObjectInput input)
              throws IOException,
                     ClassNotFoundException

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.

Throws:

IOException - if an error occurred during the I/O.

ClassNotFoundException - if it tries to load an undefined class.

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

getValueMatcher

public ValueMatcher getValueMatcher()

Specified by:

getValueMatcher in interface WriteCommand

Returns:

The current value matching policy.

setValueMatcher

public void setValueMatcher(ValueMatcher valueMatcher)

Specified by:

setValueMatcher in interface WriteCommand

Parameters:

valueMatcher - The new value matching policy.

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.

updateStatusFromRemoteResponse

public void updateStatusFromRemoteResponse(Object remoteResponse)

Description copied from interface: WriteCommand

Used for conditional commands, to update the status of the command on the originator based on the result of its execution on the primary owner.

Specified by:

updateStatusFromRemoteResponse in interface WriteCommand

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.

readsExistingValues

public boolean readsExistingValues()

Specified by:

readsExistingValues in interface VisitableCommand

Returns:

true if the command needs to read the previous values of the keys it acts on.