org.apache.ignite.spi.collision.noop

Class NoopCollisionSpi

java.lang.Object

org.apache.ignite.spi.IgniteSpiAdapter

org.apache.ignite.spi.collision.noop.NoopCollisionSpi

All Implemented Interfaces:

CollisionSpi, IgniteSpi

@IgniteSpiNoop
 @IgniteSpiMultipleInstancesSupport(value=true)
public class NoopCollisionSpi
extends IgniteSpiAdapter
implements CollisionSpi

No-op implementation of CollisionSpi. This is default implementation since 4.5.0 version. When grid is started with NoopCollisionSpi jobs are activated immediately on arrival to mapped node. This approach suits well for large amount of small jobs (which is a wide-spread use case). User still can control the number of concurrent jobs by setting maximum thread pool size defined by IgniteConfiguration.getPublicThreadPoolSize() configuration property.

Field Summary

Fields inherited from class org.apache.ignite.spi.IgniteSpiAdapter

ignite, igniteInstanceName, log

Constructor Summary

Constructors

Constructor and Description
NoopCollisionSpi()

Method Summary

Modifier and Type	Method and Description
void	onCollision(CollisionContext ctx) This is a callback called: new grid job arrived executing job finished its execution topology changed periodically (on EventType.EVT_NODE_METRICS_UPDATED) When new job arrives it is added to the end of the wait list and this method is called.
void	setExternalCollisionListener(@Nullable CollisionExternalListener lsnr) Listener to be set for notification of external collision events (e.g. job stealing).
NoopCollisionSpi	setName(String name) Sets SPI name.
void	spiStart(@Nullable String igniteInstanceName) This method is called to start SPI.
void	spiStop() This method is called to stop SPI.
String	toString()

Methods inherited from class org.apache.ignite.spi.IgniteSpiAdapter

addTimeoutObject, assertParameter, checkConfigurationConsistency0, clientFailureDetectionTimeout, configInfo, createSpiAttributeName, failureDetectionTimeout, failureDetectionTimeoutEnabled, failureDetectionTimeoutEnabled, getConsistentAttributeNames, getExceptionRegistry, getLocalNode, getName, getNodeAttributes, getSpiContext, ignite, initFailureDetectionTimeout, injectables, injectResources, isNodeStopping, onBeforeStart, onClientDisconnected, onClientReconnected, onContextDestroyed, onContextDestroyed0, onContextInitialized, onContextInitialized0, registerMBean, removeTimeoutObject, started, startInfo, startStopwatch, stopInfo, unregisterMBean

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.ignite.spi.IgniteSpi

getName, getNodeAttributes, onClientDisconnected, onClientReconnected, onContextDestroyed, onContextInitialized

Constructor Detail

NoopCollisionSpi

public NoopCollisionSpi()

Method Detail

spiStart

public void spiStart(@Nullable
                     @Nullable String igniteInstanceName)
              throws IgniteSpiException

This method is called to start SPI. After this method returns successfully kernel assumes that SPI is fully operational.

Specified by:

spiStart in interface IgniteSpi

Parameters:

igniteInstanceName - Name of Ignite instance this SPI is being started for (null for default Ignite instance).

Throws:

IgniteSpiException - Throws in case of any error during SPI start.

spiStop

public void spiStop()
             throws IgniteSpiException

This method is called to stop SPI. After this method returns kernel assumes that this SPI is finished and all resources acquired by it are released.

Note that this method can be called at any point including during recovery of failed start. It should make no assumptions on what state SPI will be in when this method is called.

Specified by:

spiStop in interface IgniteSpi

Throws:

IgniteSpiException - Thrown in case of any error during SPI stop.

onCollision

public void onCollision(CollisionContext ctx)

This is a callback called:

• new grid job arrived
• executing job finished its execution
• topology changed
• periodically (on EventType.EVT_NODE_METRICS_UPDATED)

When new job arrives it is added to the end of the wait list and this method is called. When job finished its execution, it is removed from the active list and this method is called (i.e., when grid job is finished it will not appear in any list in collision resolution).

Implementation of this method should act on all lists, each of which contains collision job contexts that define a set of operations available during collision resolution. Refer to CollisionContext and CollisionJobContext documentation for more information.

Specified by:

onCollision in interface CollisionSpi

Parameters:

ctx - Collision context which contains all collision lists.

setExternalCollisionListener

public void setExternalCollisionListener(@Nullable
                                         @Nullable CollisionExternalListener lsnr)

Listener to be set for notification of external collision events (e.g. job stealing). Once grid receives such notification, it will immediately invoke collision SPI.

Ignite uses this listener to enable job stealing from overloaded to underloaded nodes. However, you can also utilize it, for instance, to provide time based collision resolution. To achieve this, you most likely would mark some job by setting a certain attribute in job context (see ComputeJobContext) for a job that requires time-based scheduling and set some timer in your SPI implementation that would wake up after a certain period of time. Once this period is reached, you would notify this listener that a collision resolution should take place. Then inside of your collision resolution logic, you would find the marked waiting job and activate it.

Note that most collision SPI's might not have external collisions. In that case, they should simply ignore this method and do nothing when listener is set.

Specified by:

setExternalCollisionListener in interface CollisionSpi

Parameters:

lsnr - Listener for external collision events.

setName

public NoopCollisionSpi setName(String name)

Sets SPI name.

Overrides:

setName in class IgniteSpiAdapter

Parameters:

name - SPI name.

Returns:

this for chaining.

toString

public String toString()

Overrides:

toString in class Object