Package org.apache.ignite.internal.visor

Class VisorMultiNodeTask<A,R,J>

java.lang.Object

org.apache.ignite.internal.visor.VisorMultiNodeTask<A,R,J>

Type Parameters:

A - Task argument type.

R - Task result type.

J - Job result type

All Implemented Interfaces:

Serializable, ComputeTask<VisorTaskArgument<A>,VisorTaskResult<R>>

Direct Known Subclasses:

AbstractConsistencyTask, CacheDistributionTask, CacheGroupEncryptionTask, CdcCacheDataResendTask, CdcDeleteLostSegmentsTask, CheckIndexInlineSizesTask, ClientConnectionDropTask, ConnectivityTask, ConsistencyCancelTask, ContentionTask, DefragmentationTask, FetchNearXidVersionTask, FindAndDeleteGarbageInPersistenceTask, IndexForceRebuildTask, IndexRebuildStatusTask, KillTransactionTask, MetadataInfoTask, MetadataRemoveTask, MetadataUpdateTask, PageLocksTask, PropertiesListTask, PropertyTask, ReencryptionRateTask, ScheduleIndexRebuildTask, SnapshotStatusTask, SystemViewTask, TxTask, ValidateIndexesTask, VisorOneNodeTask, WalTask

public abstract class VisorMultiNodeTask<A,R,J>
extends Object
implements ComputeTask<VisorTaskArgument<A>,VisorTaskResult<R>>

Base class for Visor tasks intended to query data from a multiple node.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	debug	Debug flag.
protected IgniteEx	ignite	Auto-injected grid instance.
protected long	start	Task start time.
protected A	taskArg	Task argument.

Constructor Summary

Constructors

Constructor	Description
VisorMultiNodeTask()

Method Summary

Modifier and Type	Method	Description
protected abstract VisorJob<A,J>	job(A arg)
protected Collection<UUID>	jobNodes(VisorTaskArgument<A> arg)
@NotNull Map<? extends ComputeJob,ClusterNode>	map(List<ClusterNode> subgrid, VisorTaskArgument<A> arg)	This method is called to map or split grid task into multiple grid jobs.
protected Map<? extends ComputeJob,ClusterNode>	map0(List<ClusterNode> subgrid, VisorTaskArgument<A> arg)	Actual map logic.
@Nullable VisorTaskResult<R>	reduce(List<ComputeJobResult> results)	Reduces (or aggregates) results received so far into one compound result to be returned to caller via ComputeTaskFuture.get() method.
protected abstract R	reduce0(List<ComputeJobResult> results)	Actual reduce logic.
ComputeJobResultPolicy	result(ComputeJobResult res, List<ComputeJobResult> rcvd)	Asynchronous callback invoked every time a result from remote execution is received.

Methods inherited from class java.lang.Object

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

Field Detail

ignite

@IgniteInstanceResource
protected transient IgniteEx ignite

Auto-injected grid instance.

debug

protected boolean debug

Debug flag.

taskArg

protected A taskArg

Task argument.

start

protected long start

Task start time.

Constructor Detail

VisorMultiNodeTask

public VisorMultiNodeTask()

Method Detail

job

protected abstract VisorJob<A,J> job(A arg)

Parameters:

arg - Task arg.

Returns:

New job.

map

@NotNull
public @NotNull Map<? extends ComputeJob,ClusterNode> map(List<ClusterNode> subgrid,
                                                                VisorTaskArgument<A> arg)

This method is called to map or split grid task into multiple grid jobs. This is the first method that gets called when task execution starts.

Specified by:

map in interface ComputeTask<A,R>

Parameters:

subgrid - Nodes available for this task execution. Note that order of nodes is guaranteed to be randomized by container. This ensures that every time you simply iterate through grid nodes, the order of nodes will be random which over time should result into all nodes being used equally.

arg - Task execution argument. Can be null. This is the same argument as the one passed into Grid#execute(...) methods.

Returns:

Map of grid jobs assigned to subgrid node. Unless ComputeTaskContinuousMapper is injected into task, if null or empty map is returned, exception will be thrown.

jobNodes

protected Collection<UUID> jobNodes(VisorTaskArgument<A> arg)

Returns:

Collection of nodes IDs where jobs should be mapped.

map0

protected Map<? extends ComputeJob,ClusterNode> map0(List<ClusterNode> subgrid,
                                                           VisorTaskArgument<A> arg)

Actual map logic.

Parameters:

arg - Task execution argument.

subgrid - Nodes available for this task execution.

Returns:

Map of grid jobs assigned to subgrid node.

Throws:

IgniteException - If mapping could not complete successfully.

result

public ComputeJobResultPolicy result(ComputeJobResult res,
                                     List<ComputeJobResult> rcvd)

Asynchronous callback invoked every time a result from remote execution is received. It is ultimately upto this method to return a policy based on which the system will either wait for more results, reduce results received so far, or failover this job to another node. See ComputeJobResultPolicy for more information about result policies.

Specified by:

result in interface ComputeTask<A,R>

Parameters:

res - Received remote grid executable result.

rcvd - All previously received results. Note that if task class has ComputeTaskNoResultCache annotation, then this list will be empty.

Returns:

Result policy that dictates how to process further upcoming job results.

reduce0

@Nullable
protected abstract R reduce0(List<ComputeJobResult> results)
                      throws IgniteException

Actual reduce logic.

Parameters:

results - Job results.

Returns:

Task result.

Throws:

IgniteException - If reduction or results caused an error.

reduce

@Nullable
public final @Nullable VisorTaskResult<R> reduce(List<ComputeJobResult> results)

Reduces (or aggregates) results received so far into one compound result to be returned to caller via ComputeTaskFuture.get() method.

Note, that if some jobs did not succeed and could not be failed over then the list of results passed into this method will include the failed results. Otherwise, failed results will not be in the list.

Specified by:

reduce in interface ComputeTask<A,R>

Parameters:

results - Received results of broadcasted remote executions. Note that if task class has ComputeTaskNoResultCache annotation, then this list will be empty.

Returns:

Grid job result constructed from results of remote executions.