1 /*
2 * Copyright 2006-2013 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.io.IOException;
20 import java.util.HashMap;
21 import java.util.Map;
22
23 import org.springframework.batch.item.ExecutionContext;
24 import org.springframework.core.io.Resource;
25 import org.springframework.util.Assert;
26
27 /**
28 * Implementation of {@link Partitioner} that locates multiple resources and
29 * associates their file names with execution context keys. Creates an
30 * {@link ExecutionContext} per resource, and labels them as
31 * <code>{partition0, partition1, ..., partitionN}</code>. The grid size is
32 * ignored.
33 *
34 * @author Dave Syer
35 * @since 2.0
36 */
37 public class MultiResourcePartitioner implements Partitioner {
38
39 private static final String DEFAULT_KEY_NAME = "fileName";
40
41 private static final String PARTITION_KEY = "partition";
42
43 private Resource[] resources = new Resource[0];
44
45 private String keyName = DEFAULT_KEY_NAME;
46
47 /**
48 * The resources to assign to each partition. In Spring configuration you
49 * can use a pattern to select multiple resources.
50 * @param resources the resources to use
51 */
52 public void setResources(Resource[] resources) {
53 this.resources = resources;
54 }
55
56 /**
57 * The name of the key for the file name in each {@link ExecutionContext}.
58 * Defaults to "fileName".
59 * @param keyName the value of the key
60 */
61 public void setKeyName(String keyName) {
62 this.keyName = keyName;
63 }
64
65 /**
66 * Assign the filename of each of the injected resources to an
67 * {@link ExecutionContext}.
68 *
69 * @see Partitioner#partition(int)
70 */
71 @Override
72 public Map<String, ExecutionContext> partition(int gridSize) {
73 Map<String, ExecutionContext> map = new HashMap<String, ExecutionContext>(gridSize);
74 int i = 0;
75 for (Resource resource : resources) {
76 ExecutionContext context = new ExecutionContext();
77 Assert.state(resource.exists(), "Resource does not exist: "+resource);
78 try {
79 context.putString(keyName, resource.getURL().toExternalForm());
80 }
81 catch (IOException e) {
82 throw new IllegalArgumentException("File could not be located for: "+resource, e);
83 }
84 map.put(PARTITION_KEY + i, context);
85 i++;
86 }
87 return map;
88 }
89
90 }