org.gridgain.grid.spi.collision.noop

Class GridNoopCollisionSpi

java.lang.Object

org.gridgain.grid.spi.GridSpiAdapter

org.gridgain.grid.spi.collision.noop.GridNoopCollisionSpi

All Implemented Interfaces:

GridCollisionSpi, GridSpi, GridSpiManagementMBean

@GridSpiNoop
@GridSpiMultipleInstancesSupport(value=true)
public class GridNoopCollisionSpi
extends GridSpiAdapter
implements GridCollisionSpi

No-op implementation of GridCollisionSpi. This is default implementation since 4.5.0 version. When grid is started with GridNoopCollisionSpi 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 GridConfiguration.getExecutorService() configuration property.

Constructor Summary

Constructors

Constructor and Description
GridNoopCollisionSpi()

Method Summary

Methods

Modifier and Type	Method and Description
void	onCollision(GridCollisionContext ctx) This is a callback called when either new grid job arrived or executing job finished its execution.
void	setExternalCollisionListener(GridCollisionExternalListener lsnr) Listener to be set for notification of external collision events (e.g.
void	spiStart(String gridName) This method is called to start SPI.
void	spiStop() This method is called to stop SPI.
String	toString()

Methods inherited from class org.gridgain.grid.spi.GridSpiAdapter

assertParameter, checkConfigurationConsistency0, configInfo, createSpiAttributeName, getConsistentAttributeNames, getGridGainHome, getLocalNodeId, getName, getNodeAttributes, getSpiContext, getStartTimestamp, getStartTimestampFormatted, getUpTime, getUpTimeFormatted, injectables, onContextDestroyed, onContextDestroyed0, onContextInitialized, onContextInitialized0, registerMBean, setName, 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.gridgain.grid.spi.GridSpi

getName, getNodeAttributes, onContextDestroyed, onContextInitialized

Constructor Detail

GridNoopCollisionSpi

public GridNoopCollisionSpi()

Method Detail

spiStart

public void spiStart(@Nullable
            String gridName)
              throws GridSpiException

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

Specified by:

spiStart in interface GridSpi

Parameters:

gridName - Name of grid instance this SPI is being started for (null for default grid).

Throws:

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

spiStop

public void spiStop()
             throws GridSpiException

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 GridSpi

Throws:

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

onCollision

public void onCollision(GridCollisionContext ctx)

This is a callback called when either new grid job arrived or executing job finished its execution. 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 GridCollisionContext and GridCollisionJobContext documentation for more information.

Specified by:

onCollision in interface GridCollisionSpi

Parameters:

ctx - Collision context which contains all collision lists.

setExternalCollisionListener

public void setExternalCollisionListener(@Nullable
                                GridCollisionExternalListener 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.

GridGain 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 GridComputeJobContext) 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 GridCollisionSpi

Parameters:

lsnr - Listener for external collision events.

toString

public String toString()

Overrides:

toString in class Object