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.config.support;
17
18 import java.io.IOException;
19 import java.net.MalformedURLException;
20 import java.net.URL;
21 import java.util.Collections;
22 import java.util.Enumeration;
23 import java.util.LinkedList;
24
25 import org.slf4j.Logger;
26 import org.slf4j.LoggerFactory;
27
28 /**
29 * Utiliy methody regarding Classloader URLs.
30 */
31 public final class UrlUtil
32 {
33 // ********************************* Fields *********************************
34
35 // --- constants ------------------------------------------------------------
36
37 /**
38 * Reference to the logger for this class.
39 */
40 private static final Logger LOG = LoggerFactory.getLogger(UrlUtil.class);
41
42 // --- members --------------------------------------------------------------
43
44 // ****************************** Initializer *******************************
45
46 // ****************************** Constructors ******************************
47
48 // ****************************** Inner Classes *****************************
49
50 // ********************************* Methods ********************************
51
52 // --- init -----------------------------------------------------------------
53
54 // --- get&set --------------------------------------------------------------
55
56 // --- business -------------------------------------------------------------
57
58 // --- object basics --------------------------------------------------------
59
60 /**
61 * Get all resourceURLs of the given class loader.
62 *
63 * @param classLoader the class loader from which all resource URLs shall be
64 * fetched.
65 *
66 * @return the enumeration of resource URLs of the given class loader.
67 * @throws IOException when the URL can not be retrieved.
68 */
69 public static Enumeration<URL> getResourceUrlsFromFolder(
70 final ClassLoader classLoader, final String resourceFolderName)
71 throws IOException
72 {
73 return getResourceUrls(classLoader, resourceFolderName.endsWith("/")
74 ? resourceFolderName : resourceFolderName + "/");
75 }
76
77 /**
78 * Get all resourceURLs of the given class loader.
79 *
80 * @param classLoader the class loader from which all resource URLs shall be
81 * fetched.
82 * @return the enumeration of resource URLs of the given class loader.
83 * @throws IOException when the URL can not be retrieved.
84 */
85 public static Enumeration<URL> getResourceUrls(final ClassLoader classLoader,
86 final String resourceName) throws IOException
87 {
88 final Enumeration<URL> rootUrls = classLoader.getResources(resourceName);
89 final LinkedList<URL> rootResourceUrls = new LinkedList<URL>();
90 while (rootUrls.hasMoreElements())
91 {
92 final URL current = rootUrls.nextElement();
93 rootResourceUrls.add(shortenUrl(current, resourceName));
94 }
95 return Collections.enumeration(rootResourceUrls);
96 }
97
98 public static URL shortenUrl(final URL current, final String resourceName)
99 throws MalformedURLException
100 {
101 final String path = current.getPath();
102 String strippedPath =
103 path.substring(0, path.length() - resourceName.length());
104 strippedPath = ensureEndsWith(strippedPath, "/");
105 final URL stripped;
106 try
107 {
108 if ("jar".equals(current.getProtocol()))
109 {
110 stripped =
111 new URL("jar:" + new URL(current, strippedPath).toExternalForm());
112 }
113 else
114 {
115 stripped = new URL(current, strippedPath);
116 }
117 }
118 catch (final MalformedURLException e)
119 {
120 LOG.warn("Cannot use URL '{}' in its truncated form '{}'.", current,
121 strippedPath);
122 return current;
123 }
124 return stripped;
125 }
126
127 private static String ensureEndsWith(final String inputString,
128 final String endsWith)
129 {
130 String ensuredString = inputString;
131 if (!ensuredString.endsWith(endsWith))
132 {
133 ensuredString += endsWith;
134 }
135 return ensuredString;
136 }
137 }