1 /*
2 * Copyright 2006-2009 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.support;
18
19 import java.util.Collection;
20
21 /**
22 * <p>
23 * Optional interface for {@link Partitioner} implementations that need to use a
24 * custom naming scheme for partitions. It is not necessary to implement this
25 * interface if a partitioner extends {@link SimplePartitioner} and re-uses the
26 * default partition names.
27 * </p>
28 * <p>
29 * If a partitioner does implement this interface, however, on a restart the
30 * {@link Partitioner#partition(int)} method will not be called again, instead
31 * the partitions will be re-used from the last execution, and matched by name
32 * with the results of {@link PartitionNameProvider#getPartitionNames(int)}.
33 * This can be a useful performance optimisation if the partitioning process is
34 * expensive.
35 * </p>
36 *
37 * @author Dave Syer
38 *
39 * @since 2.1.3
40 *
41 */
42 public interface PartitionNameProvider {
43
44 Collection<String> getPartitionNames(int gridSize);
45
46 }