org.springframework.batch.core.partition.support
Class SimpleStepExecutionSplitter

java.lang.Object
  org.springframework.batch.core.partition.support.SimpleStepExecutionSplitter

All Implemented Interfaces:

StepExecutionSplitter, InitializingBean

public class SimpleStepExecutionSplitter
extends Object
implements StepExecutionSplitter, InitializingBean

Generic implementation of StepExecutionSplitter that delegates to a Partitioner to generate ExecutionContext instances. Takes care of restartability and identifying the step executions from previous runs of the same job. The generated StepExecution instances have names that identify them uniquely in the partition. The name is constructed from a base (name of the target step) plus a suffix taken from the Partitioner identifiers, separated by a colon, e.g. {step1:partition0, step1:partition1, ...}.

Since:

2.0

Author:

Dave Syer

Constructor Summary

SimpleStepExecutionSplitter()
Default constructor for convenience in configuration.

SimpleStepExecutionSplitter(JobRepository jobRepository, boolean allowStartIfComplete, String stepName, Partitioner partitioner)
Construct a SimpleStepExecutionSplitter from its mandatory properties.

SimpleStepExecutionSplitter(JobRepository jobRepository, Step step, Partitioner partitioner)
Deprecated. use SimpleStepExecutionSplitter(JobRepository, boolean, String, Partitioner) instead

Method Summary

void	afterPropertiesSet() Check mandatory properties (step name, job repository and partitioner).
String	getStepName() The name of the step configuration that will be executed remotely.
void	setAllowStartIfComplete(boolean allowStartIfComplete) Flag to indicate that the partition target step is allowed to start if an execution is complete.
void	setJobRepository(JobRepository jobRepository) The job repository that will be used to manage the persistence of the delegate step executions.
void	setPartitioner(Partitioner partitioner) The Partitioner that will be used to generate step execution meta data for the target step.
void	setStepName(String stepName) The name of the target step that will be executed across the partitions.
Set<StepExecution>	split(StepExecution stepExecution, int gridSize) Partition the provided StepExecution into a set of parallel executable instances with the same parent JobExecution.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleStepExecutionSplitter

public SimpleStepExecutionSplitter()

Default constructor for convenience in configuration.

SimpleStepExecutionSplitter

public SimpleStepExecutionSplitter(JobRepository jobRepository,
                                   boolean allowStartIfComplete,
                                   String stepName,
                                   Partitioner partitioner)

Construct a SimpleStepExecutionSplitter from its mandatory properties.

Parameters:

jobRepository - the JobRepository

allowStartIfComplete - flag specifying preferences on restart

stepName - the target step name

partitioner - a Partitioner to use for generating input parameters

SimpleStepExecutionSplitter

@Deprecated
public SimpleStepExecutionSplitter(JobRepository jobRepository,
                                              Step step,
                                              Partitioner partitioner)

Deprecated. use SimpleStepExecutionSplitter(JobRepository, boolean, String, Partitioner) instead

Construct a SimpleStepExecutionSplitter from its mandatory properties.

Parameters:

jobRepository - the JobRepository

step - the target step (a local version of it), used to extract the name and allowStartIfComplete flags

partitioner - a Partitioner to use for generating input parameters

Method Detail

afterPropertiesSet

public void afterPropertiesSet()
                        throws Exception

Check mandatory properties (step name, job repository and partitioner).

Specified by:

afterPropertiesSet in interface InitializingBean

Throws:

Exception

See Also:

InitializingBean.afterPropertiesSet()

setAllowStartIfComplete

public void setAllowStartIfComplete(boolean allowStartIfComplete)

Flag to indicate that the partition target step is allowed to start if an execution is complete. Defaults to the same value as the underlying step. Set this manually to override the underlying step properties.

Parameters:

allowStartIfComplete - the value to set

See Also:

Step.isAllowStartIfComplete()

setJobRepository

public void setJobRepository(JobRepository jobRepository)

The job repository that will be used to manage the persistence of the delegate step executions.

Parameters:

jobRepository - the JobRepository to set

setPartitioner

public void setPartitioner(Partitioner partitioner)

The Partitioner that will be used to generate step execution meta data for the target step.

Parameters:

partitioner - the partitioner to set

setStepName

public void setStepName(String stepName)

The name of the target step that will be executed across the partitions. Mandatory with no default.

Parameters:

stepName - the step name to set

getStepName

public String getStepName()

Description copied from interface: StepExecutionSplitter

The name of the step configuration that will be executed remotely. Remote workers are going to execute a the same step for each execution context in the partition.

Specified by:

getStepName in interface StepExecutionSplitter

Returns:

the name of the step that will execute the business logic

See Also:

StepExecutionSplitter.getStepName()

split

public Set<StepExecution> split(StepExecution stepExecution,
                                int gridSize)
                         throws JobExecutionException

Description copied from interface: StepExecutionSplitter

Partition the provided StepExecution into a set of parallel executable instances with the same parent JobExecution. The grid size will be treated as a hint for the size of the collection to be returned. It may or may not correspond to the physical size of an execution grid.

On a restart clients of the StepExecutionSplitter should expect it to reconstitute the state of the last failed execution and only return those executions that need to be restarted. Thus the grid size hint will be ignored on a restart.

Specified by:

split in interface StepExecutionSplitter

Parameters:

stepExecution - the StepExecution to be partitioned.

gridSize - a hint for the splitter if the size of the grid is known

Returns:

a set of StepExecution instances for remote processing

Throws:

JobExecutionException - if the split cannot be made

See Also:

StepExecutionSplitter.split(StepExecution, int)