1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.rng.examples.stress;
18
19 import picocli.CommandLine.IVersionProvider;
20
21 import java.io.IOException;
22 import java.io.InputStream;
23 import java.net.URL;
24 import java.util.Enumeration;
25 import java.util.jar.Attributes;
26 import java.util.jar.Manifest;
27
28 /**
29 * {@link IVersionProvider} implementation that returns version information from
30 * the package jar file's {@code /META-INF/MANIFEST.MF} file.
31 *
32 * @see <a
33 * href="https://github.com/remkop/picocli/blob/master/picocli-examples/src/main/java/picocli/examples/VersionProviderDemo2.java">PicoCLI
34 * version provider demo</a>
35 */
36 class ManifestVersionProvider implements IVersionProvider {
37 /** {@inheritDoc} */
38 @Override
39 public String[] getVersion() throws Exception {
40 final Enumeration<URL> resources = Thread.currentThread().getContextClassLoader()
41 .getResources("META-INF/MANIFEST.MF");
42 while (resources.hasMoreElements()) {
43 final URL url = resources.nextElement();
44 try (InputStream stream = url.openStream()) {
45 final Manifest manifest = new Manifest(stream);
46 if (isApplicableManifest(manifest)) {
47 final Attributes attr = manifest.getMainAttributes();
48 return new String[] {get(attr, "Implementation-Title") + " version \"" +
49 get(attr, "Implementation-Version") + "\""};
50 }
51 } catch (final IOException ex) {
52 return new String[] {"Unable to read from " + url + ". " + ex};
53 }
54 }
55 return new String[0];
56 }
57
58 /**
59 * Checks if this is the applicable manifest for the package.
60 *
61 * @param manifest The manifest.
62 * @return true if is the applicable manifest
63 */
64 private static boolean isApplicableManifest(Manifest manifest) {
65 final Attributes attributes = manifest.getMainAttributes();
66 return "org.apache.commons.rng.examples.stress".equals(get(attributes, "Automatic-Module-Name"));
67 }
68
69 /**
70 * Gets the named object from the attributes using the key.
71 *
72 * @param attributes The attributes.
73 * @param key The key.
74 * @return the object
75 */
76 private static Object get(Attributes attributes, String key) {
77 return attributes.get(new Attributes.Name(key));
78 }
79 }