org.gridgain.grid.spi.collision.fifoqueue
Class GridFifoQueueCollisionSpi

java.lang.Object
  org.gridgain.grid.spi.GridSpiAdapter
      org.gridgain.grid.spi.collision.fifoqueue.GridFifoQueueCollisionSpi

All Implemented Interfaces:

GridFifoQueueCollisionSpiMBean, GridCollisionSpi, GridSpi, GridSpiManagementMBean

@GridSpiInfo(author="GridGain Systems",
             url="www.gridgain.org",
             email="support@gridgain.com",
             version="x.x")
@GridSpiMultipleInstancesSupport(value=true)
public class GridFifoQueueCollisionSpi
extends GridSpiAdapter
implements GridCollisionSpi, GridFifoQueueCollisionSpiMBean

This class provides implementation for Collision SPI based on FIFO queue. Jobs are ordered as they arrived and only GridFifoQueueCollisionSpi.getParallelJobsNumber() number of jobs is allowed to execute in parallel. Other jobs will be buffered in the passive queue.

Configuration

Mandatory

This SPI has no mandatory configuration parameters.

Optional

This SPI has following optional configuration parameters:

• Number of jobs that can execute in parallel (see GridFifoQueueCollisionSpi.setParallelJobsNumber(int)). This number should usually be set to the number of threads in the execution thread pool.

Java Example

GridFifoQueueCollisionSpi can be configured as follows:

 GridFifoQueueCollisionSpi colSpi = new GridFifoQueueCollisionSpi();

 // Execute all jobs sequentially by setting parallel job number to 1.
 colSpi.setParallelJobsNumber(1);

 GridConfigurationAdapter cfg = new GridConfigurationAdapter();

 // Override default collision SPI.
 cfg.setCollisionSpi(colSpi);

 // Start grid.
 GridFactory.start(cfg);
 

Spring Example

GridFifoQueueCollisionSpi can be configured from Spring XML configuration file:

 <bean id="grid.custom.cfg" class="org.gridgain.grid.GridConfigurationAdapter" singleton="true">
       ...
       <property name="collisionSpi">
           <bean class="org.gridgain.grid.spi.collision.fifoqueue.GridFifoQueueCollisionSpi">
               <property name="parallelJobsNumber" value="1"/>
           </bean>
       </property>
       ...
 </bean>
 

See Also:

Documentation
Email Support
Online Forums
Issue Tracking

Author: 2005-2008 Copyright © GridGain Systems. All Rights Reserved. ver. 2.0.3

	Nikita Ivanov, GridGain Systems nivanov@gridgain.com
	Dmitriy Setrakyan, GridGain Systems dsetrakyan@gridgain.com
	Alexander Magdenko, GridGain Systems amagdenko@gridgain.com
	Boris Suchodoev, GridGain Systems bsuchodoev@gridgain.com
	Denis Kharlamov, GridGain Systems dkharlamov@gridgain.com
	close

Field Summary

static int

DFLT_PARALLEL_JOBS_NUM Default number of parallel jobs allowed (value is 95 which is slightly less same as default value of threads in the execution thread pool to allow some extra threads for system processing).

Constructor Summary

GridFifoQueueCollisionSpi()

Method Summary

int	getCurrentActiveJobsNumber() Gets current number of jobs that are being executed.
int	getCurrentWaitJobsNumber() Gets current number of jobs that wait for the execution.
int	getParallelJobsNumber() Gets number of jobs that can be executed in parallel.
void	onCollision(Collection<GridCollisionJobContext> waitJobs, Collection<GridCollisionJobContext> activeJobs) This is a callback called when either new grid job arrived or executing job finished its execution.
void	setExternalCollisionListener(GridCollisionExternalListener listener) Listener to be set for notification of external collision events (e.g. job stealing).
void	setParallelJobsNumber(int parallelJobsNum) Sets number of jobs that are allowed to be executed in parallel on this node.
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, checkConfigurationConsistency, configInfo, getAuthor, getGridGainHome, getLocalNodeId, getNodeAttributes, getSpiContext, getStartTimestamp, getStartTimestampFormatted, getUpTime, getUpTimeFormatted, getVendorEmail, getVendorUrl, getVersion, onContextDestroyed, onContextInitialized, registerMBean, setSpiContext, startInfo, startStopwatch, stopInfo, unregisterMBean, warnSpi, warnSpiParameter

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

getNodeAttributes, onContextDestroyed, onContextInitialized

Methods inherited from interface org.gridgain.grid.spi.GridSpiManagementMBean

getAuthor, getGridGainHome, getLocalNodeId, getStartTimestamp, getStartTimestampFormatted, getUpTime, getUpTimeFormatted, getVendorEmail, getVendorUrl, getVersion

Field Detail

DFLT_PARALLEL_JOBS_NUM

public static final int DFLT_PARALLEL_JOBS_NUM

Default number of parallel jobs allowed (value is 95 which is slightly less same as default value of threads in the execution thread pool to allow some extra threads for system processing).

See Also:

Constant Field Values

Constructor Detail

GridFifoQueueCollisionSpi

public GridFifoQueueCollisionSpi()

Method Detail

setParallelJobsNumber

@GridSpiConfiguration(optional=true)
public void setParallelJobsNumber(int parallelJobsNum)

Sets number of jobs that are allowed to be executed in parallel on this node. If not provided, default value is GridFifoQueueCollisionSpi.DFLT_PARALLEL_JOBS_NUM.

Parameters:

parallelJobsNum - Maximum number of jobs to be executed in parallel.

getParallelJobsNumber

public int getParallelJobsNumber()

Gets number of jobs that can be executed in parallel.

Specified by:

getParallelJobsNumber in interface GridFifoQueueCollisionSpiMBean

Returns:

Number of jobs that can be executed in parallel.

getCurrentWaitJobsNumber

public int getCurrentWaitJobsNumber()

Gets current number of jobs that wait for the execution.

Specified by:

getCurrentWaitJobsNumber in interface GridFifoQueueCollisionSpiMBean

Returns:

Number of jobs that wait for execution.

getCurrentActiveJobsNumber

public int getCurrentActiveJobsNumber()

Gets current number of jobs that are being executed.

Specified by:

getCurrentActiveJobsNumber in interface GridFifoQueueCollisionSpiMBean

Returns:

Number of active jobs.

spiStart

public void spiStart(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

Throws:

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

Parameters:

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

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.

setExternalCollisionListener

public void setExternalCollisionListener(GridCollisionExternalListener listener)

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 GridJobContext) 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 may 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:

listener - Listener for external collision events.

onCollision

public void onCollision(Collection<GridCollisionJobContext> waitJobs,
                        Collection<GridCollisionJobContext> activeJobs)

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 two lists, each of which contains collision job contexts that define a set of operations available during collision resolution. Refer to GridCollisionJobContext documentation for more information.

Specified by:

onCollision in interface GridCollisionSpi

Parameters:

waitJobs - Ordered collection of collision contexts for jobs that are currently waiting for execution. It can be empty but never null. Note that a new newly arrived job, if any, will always be represented by the last item in this list.

activeJobs - Ordered collection of collision contexts for jobs that are currently executing. It can be empty but never null.

toString

public String toString()

Overrides:

toString in class Object