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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  package org.springframework.batch.core.configuration.support;
17  
18  import java.util.Collections;
19  import java.util.Set;
20  import java.util.concurrent.ConcurrentHashMap;
21  import java.util.concurrent.ConcurrentMap;
22  
23  import org.springframework.batch.core.Job;
24  import org.springframework.batch.core.configuration.DuplicateJobException;
25  import org.springframework.batch.core.configuration.JobFactory;
26  import org.springframework.batch.core.configuration.JobRegistry;
27  import org.springframework.batch.core.launch.NoSuchJobException;
28  import org.springframework.util.Assert;
29  
30  /**
31   * Simple, thread-safe, map-based implementation of {@link JobRegistry}.
32   *
33   * @author Dave Syer
34   * @author Robert Fischer
35   */
36  public class MapJobRegistry implements JobRegistry {
37  
38  	/**
39  	 * The map holding the registered job factories.
40  	 */
41  	// The "final" ensures that it is visible and initialized when the constructor resolves.
42  	private final ConcurrentMap<String, JobFactory> map = new ConcurrentHashMap<String, JobFactory>();
43  
44  	@Override
45  	public void register(JobFactory jobFactory) throws DuplicateJobException {
46  		Assert.notNull(jobFactory);
47  		String name = jobFactory.getJobName();
48  		Assert.notNull(name, "Job configuration must have a name.");
49  		JobFactory previousValue = map.putIfAbsent(name, jobFactory);
50  		if (previousValue != null) {
51  			throw new DuplicateJobException("A job configuration with this name [" + name
52  					+ "] was already registered");
53  		}
54  	}
55  
56  	@Override
57  	public void unregister(String name) {
58  		Assert.notNull(name, "Job configuration must have a name.");
59  		map.remove(name);
60  	}
61  
62  	@Override
63  	public Job getJob(String name) throws NoSuchJobException {
64  		JobFactory factory = map.get(name);
65  		if (factory == null) {
66  			throw new NoSuchJobException("No job configuration with the name [" + name + "] was registered");
67  		} else {
68  			return factory.createJob();
69  		}
70  	}
71  
72  	/**
73  	 * Provides an unmodifiable view of the job names.
74  	 */
75  	@Override
76  	public Set<String> getJobNames() {
77  		return Collections.unmodifiableSet(map.keySet());
78  	}
79  
80  }