java.util.Set<StepExecution> split(StepExecution stepExecution, int gridSize) throws JobExecutionException
StepExecutioninto 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.
StepExecutionSplittershould 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.