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
18 package org.apache.commons.lang3;
19
20 import java.net.URL;
21 import java.net.URLClassLoader;
22 import java.util.Arrays;
23 import java.util.Objects;
24
25 /**
26 * Helps work with {@link ClassLoader}.
27 *
28 * @since 3.10
29 */
30 public class ClassLoaderUtils {
31
32 private static final URL[] EMPTY_URL_ARRAY = new URL[] {};
33
34 /**
35 * Gets the system class loader's URLs, if any.
36 *
37 * @return the system class loader's URLs, if any.
38 * @since 3.13.0
39 */
40 public static URL[] getSystemURLs() {
41 return getURLs(ClassLoader.getSystemClassLoader());
42 }
43
44 /**
45 * Gets the current thread's context class loader's URLs, if any.
46 *
47 * @return the current thread's context class loader's URLs, if any.
48 * @since 3.13.0
49 */
50 public static URL[] getThreadURLs() {
51 return getURLs(Thread.currentThread().getContextClassLoader());
52 }
53
54 private static URL[] getURLs(final ClassLoader cl) {
55 return cl instanceof URLClassLoader ? ((URLClassLoader) cl).getURLs() : EMPTY_URL_ARRAY;
56 }
57
58 /**
59 * Converts the given class loader to a String calling {@link #toString(URLClassLoader)}.
60 *
61 * @param classLoader to URLClassLoader to convert.
62 * @return the formatted string.
63 */
64 public static String toString(final ClassLoader classLoader) {
65 if (classLoader instanceof URLClassLoader) {
66 return toString((URLClassLoader) classLoader);
67 }
68 return Objects.toString(classLoader);
69 }
70
71 /**
72 * Converts the given URLClassLoader to a String in the format {@code "URLClassLoader.toString() + [URL1, URL2, ...]"}.
73 *
74 * @param classLoader to URLClassLoader to convert.
75 * @return the formatted string.
76 */
77 public static String toString(final URLClassLoader classLoader) {
78 return classLoader != null ? classLoader + Arrays.toString(classLoader.getURLs()) : "null";
79 }
80 }