com.hazelcast.journal

Class EventJournalReadOperation<T,J>

java.lang.Object

com.hazelcast.spi.Operation

com.hazelcast.journal.EventJournalReadOperation<T,J>

Type Parameters:

T - the return type of the projection. It is equal to the journal event type if the projection is null or it is the identity projection

J - journal event type

All Implemented Interfaces:

DataSerializable, IdentifiedDataSerializable, BlockingOperation, PartitionAwareOperation

Direct Known Subclasses:

CacheEventJournalReadOperation, MapEventJournalReadOperation

public abstract class EventJournalReadOperation<T,J>
extends Operation
implements IdentifiedDataSerializable, PartitionAwareOperation, BlockingOperation

Reads from the map event journal in batches. You may specify the start sequence, the minumum required number of items in the response, the maximum number of items in the response, a predicate that the events should pass and a projection to apply to the events in the journal. If the event journal currently contains less events than the required minimum, the call will wait until it has sufficient items. The predicate, filter and projection may be null in which case all elements are returned and no projection is applied.

Since:

3.9

Field Summary

Fields

Modifier and Type	Field and Description
protected int	maxSize
protected int	minSize
protected String	name
protected DistributedObjectNamespace	namespace
protected ReadResultSetImpl<J,T>	resultSet
protected long	sequence
protected long	startSequence

Fields inherited from class com.hazelcast.spi.Operation

GENERIC_PARTITION_ID

Constructor Summary

Constructors

Constructor and Description
EventJournalReadOperation()
EventJournalReadOperation(String name, long startSequence, int minSize, int maxSize)

Method Summary

Modifier and Type	Method and Description
void	beforeRun() Checks the precondition that the start sequence is already available (in the event journal) or is the sequence of the next event to be added into the journal.
protected abstract ReadResultSetImpl<J,T>	createResultSet()
protected abstract EventJournal<J>	getJournal()
Object	getResponse()
abstract String	getServiceName()
WaitNotifyKey	getWaitKey()
void	logError(Throwable e) Logs Exception/Error thrown during operation execution.
void	onWaitExpire()
protected void	readInternal(ObjectDataInput in)
void	run()
boolean	shouldWait() On every invocation this method reads from the event journal until it has collected the minimum required number of response items.
protected void	writeInternal(ObjectDataOutput out)

Methods inherited from class com.hazelcast.spi.Operation

afterRun, executedLocally, getCallerAddress, getCallerUuid, getCallId, getCallTimeout, getConnection, getInvocationTime, getLogger, getNodeEngine, getOperationResponseHandler, getPartitionId, getReplicaIndex, getService, getWaitTimeout, isUrgent, onExecutionFailure, onInvocationException, onSetCallId, readData, returnsResponse, sendResponse, setCallerUuid, setNodeEngine, setOperationResponseHandler, setPartitionId, setReplicaIndex, setService, setServiceName, setValidateTarget, setWaitTimeout, toString, toString, validatesTarget, writeData

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.hazelcast.nio.serialization.IdentifiedDataSerializable

getFactoryId, getId

Methods inherited from interface com.hazelcast.nio.serialization.DataSerializable

readData, writeData

Methods inherited from interface com.hazelcast.spi.PartitionAwareOperation

getPartitionId

Methods inherited from interface com.hazelcast.spi.BlockingOperation

getWaitTimeout

Field Detail

name

protected String name

minSize

protected int minSize

maxSize

protected int maxSize

startSequence

protected long startSequence

resultSet

protected transient ReadResultSetImpl<J,T> resultSet

sequence

protected transient long sequence

namespace

protected transient DistributedObjectNamespace namespace

Constructor Detail

EventJournalReadOperation

public EventJournalReadOperation()

EventJournalReadOperation

public EventJournalReadOperation(String name,
                                 long startSequence,
                                 int minSize,
                                 int maxSize)

Method Detail

beforeRun

public void beforeRun()

Checks the precondition that the start sequence is already available (in the event journal) or is the sequence of the next event to be added into the journal.

Overrides:

beforeRun in class Operation

shouldWait

public boolean shouldWait()

On every invocation this method reads from the event journal until it has collected the minimum required number of response items. Returns true if there are currently not enough elements in the response and the operation should be parked.

Specified by:

shouldWait in interface BlockingOperation

Returns:

if the operation should wait on the wait/notify key

run

public void run()
         throws Exception

Specified by:

run in class Operation

Throws:

Exception

getResponse

public Object getResponse()

Overrides:

getResponse in class Operation

getWaitKey

public WaitNotifyKey getWaitKey()

Specified by:

getWaitKey in interface BlockingOperation

onWaitExpire

public void onWaitExpire()

Specified by:

onWaitExpire in interface BlockingOperation

writeInternal

protected void writeInternal(ObjectDataOutput out)
                      throws IOException

Overrides:

writeInternal in class Operation

Throws:

IOException

readInternal

protected void readInternal(ObjectDataInput in)
                     throws IOException

Overrides:

readInternal in class Operation

Throws:

IOException

logError

public void logError(Throwable e)

Description copied from class: Operation

Logs Exception/Error thrown during operation execution. Operation implementations can override this behaviour due to their needs.

This method is called on node & thread that's executing the operation.

Overrides:

logError in class Operation

Parameters:

e - Exception/Error thrown during operation execution

getServiceName

public abstract String getServiceName()

Overrides:

getServiceName in class Operation

createResultSet

protected abstract ReadResultSetImpl<J,T> createResultSet()

getJournal

protected abstract EventJournal<J> getJournal()