org.gridgain.grid.spi.failover
Interface GridFailoverSpi

All Superinterfaces:

GridSpi

All Known Implementing Classes:

GridAlwaysFailoverSpi, GridJobStealingFailoverSpi, GridNeverFailoverSpi

@Apache20LicenseCompatible
public interface GridFailoverSpi
extends GridSpi

Failover SPI provides developer with ability to supply custom logic for handling failed execution of a grid job. Job execution can fail for a number of reasons:

• Job execution threw an exception (runtime, assertion or error)
• Node on which job was execution left topology (crashed or stopped)
• Collision SPI on remote node cancelled a job before it got a chance to execute (job rejection).

In all cases failover SPI takes failed job (as failover context) and list of all grid nodes and provides another node on which the job execution will be retried. It is up to failover SPI to make sure that job is not mapped to the node it failed on. The failed node can be retrieved from GridFailoverContext.getJobResult().getNode() method.

GridGain comes with the following built-in failover SPI implementations:

• GridNeverFailoverSpi
• GridAlwaysFailoverSpi
• GridJobStealingFailoverSpi

See Also:

Documentation
Email Support
Online Forums
Issue Tracking

Author: 2005-2008 Copyright © GridGain Systems. All Rights Reserved. ver. 2.1.0

	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

Method Summary

GridNode

failover(GridFailoverContext ctx, List<GridNode> top) This method is called when method GridTask.result(GridJobResult, List) returns value GridJobResultPolicy.FAILOVER policy indicating that the result of job execution must be failed over.

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

getName, getNodeAttributes, onContextDestroyed, onContextInitialized, spiStart, spiStop

Method Detail

failover

GridNode failover(GridFailoverContext ctx,
                  List<GridNode> top)

This method is called when method GridTask.result(GridJobResult, List) returns value GridJobResultPolicy.FAILOVER policy indicating that the result of job execution must be failed over. Implementation of this method should examine failover context and choose one of the grid nodes from supplied topology to retry job execution on it. For best performance it is advised that GridFailoverContext.getBalancedNode(List) method is used to select node for execution of failed job.

Parameters:

ctx - Failover context.

top - Collection of all grid nodes within task topology (may include failed node).

Returns:

New node to route this job to or null if new node cannot be picked. If job failover fails (returns null) the whole task will be failed.