1 /*
2 * Licensed under the Apache License, Version 2.0 (the "License");
3 * you may not use this file except in compliance with the License.
4 * You may obtain a copy of the License at
5 *
6 * http://www.apache.org/licenses/LICENSE-2.0
7 *
8 * Unless required by applicable law or agreed to in writing, software
9 * distributed under the License is distributed on an "AS IS" BASIS,
10 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 * See the License for the specific language governing permissions and
12 * limitations under the License.
13 */
14 package org.apache.commons.classscan;
15
16 import java.util.Collection;
17 import java.util.Iterator;
18
19 import org.apache.commons.classscan.model.MetaClass;
20
21 /**
22 * Metadata about a ClassLoader. This includes the jars that a ClassLoader loads
23 * from and the Classes that are potentially available.
24 */
25 public interface MetaClassLoader {
26 /**
27 * Get the metadata about the parent of the associated ClassLoader.
28 *
29 * @return The parent metadata. This will be null if the associated
30 * ClassLoader is the primordial ClassLoader.
31 */
32 MetaClassLoader getParent();
33
34 /**
35 * Get metadata about the locations from which the associated ClassLoader
36 * loads Classes.
37 *
38 * @return A read-only set of code locations
39 */
40 Collection<? extends MetaClassPathElement> getClassLocations();
41
42 /**
43 * Get metadata about a class locations
44 *
45 * @param codeLocation
46 * The location of a folder, jar, or compressed code
47 */
48 MetaClassPathElement getClassLocation(String codeLocation);
49
50 /**
51 * Get metadata about the Classes from which the associated ClassLoader can
52 * load.
53 *
54 * @return A read-only set of class information
55 */
56 Iterator<? extends MetaClass> getMetaClasses();
57
58 /**
59 * Get metadata about a particular Class. This method will return only
60 * classes defined by the associated ClassLoader. Classes defined by a
61 * parent ClassLoader can be found using {@link #findMetaClass}.
62 *
63 * @param className
64 * The name of the Class
65 * @return The metadata about the Class; or null, if the class was not
66 * available to the associated ClassLoader
67 */
68 MetaClass getMetaClass(String className);
69
70 /**
71 * Find metadata about a particular Class. This method will first search up
72 * the associated parent ClassLoader chain.
73 *
74 * @param className
75 * The name of the Class
76 * @return The metadata about the Class; or null, if the class was not
77 * available to the associated ClassLoader not its parent chain
78 */
79 MetaClass findMetaClass(String className);
80
81 /**
82 * Find all the implementors of an interface class. This method will search
83 * in the associated ClassLoader and all parents.
84 *
85 * @param interfaceToFind
86 * The non-null MetaClass associated with the
87 *
88 * @return All discovered implementors of the desired interface
89 */
90 Collection<? extends MetaClass> findAllImplementors(String interfaceToFind);
91 }