1 /*
2 * Portions of this software was developed by employees of the National Institute
3 * of Standards and Technology (NIST), an agency of the Federal Government and is
4 * being made available as a public service. Pursuant to title 17 United States
5 * Code Section 105, works of NIST employees are not subject to copyright
6 * protection in the United States. This software may be subject to foreign
7 * copyright. Permission in the United States and in foreign countries, to the
8 * extent that NIST may hold copyright, to use, copy, modify, create derivative
9 * works, and distribute this software and its documentation without fee is hereby
10 * granted on a non-exclusive basis, provided that this notice and disclaimer
11 * of warranty appears in all copies.
12 *
13 * THE SOFTWARE IS PROVIDED 'AS IS' WITHOUT ANY WARRANTY OF ANY KIND, EITHER
14 * EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, ANY WARRANTY
15 * THAT THE SOFTWARE WILL CONFORM TO SPECIFICATIONS, ANY IMPLIED WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND FREEDOM FROM
17 * INFRINGEMENT, AND ANY WARRANTY THAT THE DOCUMENTATION WILL CONFORM TO THE
18 * SOFTWARE, OR ANY WARRANTY THAT THE SOFTWARE WILL BE ERROR FREE. IN NO EVENT
19 * SHALL NIST BE LIABLE FOR ANY DAMAGES, INCLUDING, BUT NOT LIMITED TO, DIRECT,
20 * INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES, ARISING OUT OF, RESULTING FROM,
21 * OR IN ANY WAY CONNECTED WITH THIS SOFTWARE, WHETHER OR NOT BASED UPON WARRANTY,
22 * CONTRACT, TORT, OR OTHERWISE, WHETHER OR NOT INJURY WAS SUSTAINED BY PERSONS OR
23 * PROPERTY OR OTHERWISE, AND WHETHER OR NOT LOSS WAS SUSTAINED FROM, OR AROSE OUT
24 * OF THE RESULTS OF, OR USE OF, THE SOFTWARE OR SERVICES PROVIDED HEREUNDER.
25 */
26
27 package gov.nist.secauto.metaschema.cli.processor.command;
28
29 import java.util.List;
30 import java.util.ServiceLoader;
31 import java.util.ServiceLoader.Provider;
32 import java.util.stream.Collectors;
33
34 import edu.umd.cs.findbugs.annotations.NonNull;
35 import nl.talsmasoftware.lazy4j.Lazy;
36
37 public final class CommandService {
38 private static final Lazy<CommandService> INSTANCE = Lazy.lazy(() -> new CommandService());
39 @NonNull
40 private final ServiceLoader<ICommand> loader;
41
42 /**
43 * Get the singleton instance of the function service.
44 *
45 * @return the service instance
46 */
47 public static CommandService getInstance() {
48 return INSTANCE.get();
49 }
50
51 public CommandService() {
52 ServiceLoader<ICommand> loader = ServiceLoader.load(ICommand.class);
53 assert loader != null;
54 this.loader = loader;
55 }
56
57 /**
58 * Get the function service loader instance.
59 *
60 * @return the service loader instance.
61 */
62 @NonNull
63 private ServiceLoader<ICommand> getLoader() {
64 return loader;
65 }
66
67 @SuppressWarnings("null")
68 @NonNull
69 public List<ICommand> getCommands() {
70 return getLoader().stream()
71 .map(Provider<ICommand>::get)
72 .collect(Collectors.toUnmodifiableList());
73 }
74 }