/*
* Copyright 2006-2007 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.batch.core.partition;
import java.util.Set;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobExecutionException;
import org.springframework.batch.core.StepExecution;
/**
* Strategy interface for generating input contexts for a partitioned step
* execution independent from the fabric they are going to run on.
*
* @author Dave Syer
* @since 2.0
*/
public 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.
* @return the name of the step that will execute the business logic
*/
String getStepName();
/**
* Partition the provided {@link StepExecution} into a set of parallel
* executable instances with the same parent {@link 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.<br/>
* <br/>
*
* On a restart clients of the {@link 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.
*
* @param stepExecution the {@link StepExecution} to be partitioned.
* @param gridSize a hint for the splitter if the size of the grid is known
* @return a set of {@link StepExecution} instances for remote processing
*
* @throws JobExecutionException if the split cannot be made
*/
Set<StepExecution> split(StepExecution stepExecution, int gridSize) throws JobExecutionException;
}
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