1 /*
2 * Copyright 2006-2007 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.batch.core.partition;
18
19 import java.util.Set;
20
21 import org.springframework.batch.core.JobExecution;
22 import org.springframework.batch.core.JobExecutionException;
23 import org.springframework.batch.core.StepExecution;
24
25 /**
26 * Strategy interface for generating input contexts for a partitioned step
27 * execution independent from the fabric they are going to run on.
28 *
29 * @author Dave Syer
30 * @since 2.0
31 */
32 public interface StepExecutionSplitter {
33
34 /**
35 * The name of the step configuration that will be executed remotely. Remote
36 * workers are going to execute a the same step for each execution context
37 * in the partition.
38 * @return the name of the step that will execute the business logic
39 */
40 String getStepName();
41
42 /**
43 * Partition the provided {@link StepExecution} into a set of parallel
44 * executable instances with the same parent {@link JobExecution}. The grid
45 * size will be treated as a hint for the size of the collection to be
46 * returned. It may or may not correspond to the physical size of an
47 * execution grid.<br/>
48 * <br/>
49 *
50 * On a restart clients of the {@link StepExecutionSplitter} should expect
51 * it to reconstitute the state of the last failed execution and only return
52 * those executions that need to be restarted. Thus the grid size hint will
53 * be ignored on a restart.
54 *
55 * @param stepExecution the {@link StepExecution} to be partitioned.
56 * @param gridSize a hint for the splitter if the size of the grid is known
57 * @return a set of {@link StepExecution} instances for remote processing
58 *
59 * @throws JobExecutionException if the split cannot be made
60 */
61 Set<StepExecution> split(StepExecution stepExecution, int gridSize) throws JobExecutionException;
62
63 }