1 /*
2 * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
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 de.smartics.properties.spi.core.classpath;
17
18 import java.net.URL;
19 import java.net.URLClassLoader;
20 import java.util.Collection;
21 import java.util.Collections;
22 import java.util.Set;
23
24 import org.reflections.Reflections;
25 import org.reflections.scanners.TypeAnnotationsScanner;
26 import org.reflections.util.ConfigurationBuilder;
27
28 import de.smartics.properties.api.core.annotations.PropertySet;
29
30 /**
31 * Loads classes that have a {@link PropertySet} annotation.
32 */
33 public final class PropertySetClassesLoader
34 {
35 // ********************************* Fields *********************************
36
37 // --- constants ------------------------------------------------------------
38
39 /**
40 * Default scanner to use.
41 */
42 private static final TypeAnnotationsScanner SCANNER =
43 new TypeAnnotationsScanner();
44
45 // --- members --------------------------------------------------------------
46
47 // ****************************** Initializer *******************************
48
49 // ****************************** Constructors ******************************
50
51 // ****************************** Inner Classes *****************************
52
53 // ********************************* Methods ********************************
54
55 // --- init -----------------------------------------------------------------
56
57 private static Reflections buildReflections(final Collection<URL> urls)
58 {
59 final ClassLoader classLoader =
60 new URLClassLoader(urls.toArray(new URL[urls.size()]), Thread
61 .currentThread().getContextClassLoader());
62
63 final ConfigurationBuilder builder = new ConfigurationBuilder();
64 builder.setScanners(SCANNER).addClassLoader(classLoader).addUrls(urls);
65 final Reflections reflections = new Reflections(builder);
66 return reflections;
67 }
68
69 // --- get&set --------------------------------------------------------------
70
71 // --- business -------------------------------------------------------------
72
73 /**
74 * Returns all types that are annotated as property set.
75 *
76 * @param urls the class roots to search for types that have the required
77 * annotation.
78 * @return the set of types that are annotated with {@link PropertySet}.
79 */
80 public Set<Class<?>> getPropertySetTypes(final Collection<URL> urls)
81 {
82 if (urls == null || urls.isEmpty())
83 {
84 return Collections.emptySet();
85 }
86
87 final Reflections reflections = buildReflections(urls);
88 final Set<Class<?>> propertySetTypes =
89 reflections.getTypesAnnotatedWith(PropertySet.class);
90
91 return propertySetTypes;
92 }
93
94 // --- object basics --------------------------------------------------------
95
96 }