1 // ========================================================================
2 // Copyright (c) 2009 Intalio, Inc.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13 package org.eclipse.jetty.osgi.boot.internal.webapp;
14
15 import java.io.File;
16 import java.net.MalformedURLException;
17 import java.net.URL;
18 import java.net.URLClassLoader;
19 import java.util.ArrayList;
20 import java.util.HashMap;
21 import java.util.HashSet;
22 import java.util.Map;
23 import java.util.Set;
24
25 import org.eclipse.jetty.server.Server;
26 import org.eclipse.jetty.webapp.WebAppContext;
27
28 /**
29 * Helper to create a URL class-loader with the jars inside
30 * ${jetty.home}/lib/ext and ${jetty.home}/resources. In an ideal world, every
31 * library is an OSGi bundle that does loads nicely. To support standard jars or
32 * bundles that cannot be loaded in the current OSGi environment, we support
33 * inserting the jars in the usual jetty/lib/ext folders in the proper classpath
34 * for the webapps.
35 * <p>
36 * Also the folder resources typically contains central configuration files for
37 * things like: log config and others. We enable fragments to register classes
38 * that are called back and passed those resources to do what they need to do.
39 * </p>
40 * <p>
41 * For example the test-jndi webapplication depends on derby, derbytools,
42 * atomikos none of them are osgi bundles. we can either re-package them or we
43 * can place them in the usual lib/ext. <br/>
44 * In fact jasper's jsp libraries should maybe place in lib/ext too.
45 * </p>
46 * <p>
47 * The drawback is that those libraries will not be available in the OSGi
48 * classloader. Note that we could have setup those jars as embedded jars of the
49 * current bundle. However, we would need to know in advance what are those jars
50 * which was not acceptable. Also having those jars in a URLClassLoader seem to
51 * be required for some cases. For example jaspers' TldLocationsCache (replaced
52 * by TldScanner for servlet-3.0). <br/>
53 * Also all the dependencies of those libraries must be resolvable directly from
54 * the JettyBooStrapper bundle as it is set as the parent classloader. For
55 * example: if atomikos is placed in lib/ext it will work if and only if
56 * JettyBootStrapper import the necessary packages from javax.naming*,
57 * javax.transaction*, javax.mail* etc Most of the common cases of javax are
58 * added as optional import packages into jetty bootstrapper plugin. When there
59 * are not covered: please make a request or create a fragment or register a
60 * bundle with a buddy-policy onto the jetty bootstrapper..
61 * </p>
62 * <p>
63 * Alternatives to placing jars in lib/ext
64 * <ol>
65 * <li>Bundle the jars in an osgi bundle. Have the webapp(s) that context
66 * depends on them depend on that bundle. Things will go well for jetty.</li>
67 * <li>Bundle those jars in an osgi bundle-fragment that targets the
68 * jetty-bootstrap bundle</li>
69 * <li>Use equinox Buddy-Policy: register a buddy of the jetty bootstrapper
70 * bundle. (least favorite: it will work only on equinox)</li>
71 * </ol>
72 * </p>
73 */
74 public class LibExtClassLoaderHelper
75 {
76
77 /**
78 * Class called back
79 */
80 public interface IFilesInJettyHomeResourcesProcessor
81 {
82 void processFilesInResourcesFolder(File jettyHome, Map<String, File> filesInResourcesFolder);
83 }
84
85 public static Set<IFilesInJettyHomeResourcesProcessor> registeredFilesInJettyHomeResourcesProcessors = new HashSet<IFilesInJettyHomeResourcesProcessor>();
86
87 /**
88 * @param server
89 * @return a url classloader with the jars of resources, lib/ext and the
90 * jars passed in the other argument. The parent classloader usually
91 * is the JettyBootStrapper (an osgi classloader.
92 * @throws MalformedURLException
93 */
94 public static URLClassLoader createLibEtcClassLoaderHelper(File jettyHome, Server server, ClassLoader parentClassLoader) throws MalformedURLException
95 {
96
97 ArrayList<URL> urls = new ArrayList<URL>();
98 File jettyResources = new File(jettyHome,"resources");
99 if (jettyResources.exists())
100 {
101 // make sure it contains something else than README:
102 Map<String, File> jettyResFiles = new HashMap<String, File>();
103 for (File f : jettyResources.listFiles())
104 {
105 jettyResFiles.put(f.getName(),f);
106 if (f.getName().toLowerCase().startsWith("readme"))
107 {
108 continue;
109 }
110 else
111 {
112 if (urls.isEmpty())
113 {
114 urls.add(jettyResources.toURI().toURL());
115 }
116 }
117 }
118 processFilesInResourcesFolder(jettyHome,jettyResFiles);
119 }
120 File libExt = new File(jettyHome,"lib/ext");
121 if (libExt.exists())
122 {
123 for (File f : libExt.listFiles())
124 {
125 if (f.getName().endsWith(".jar"))
126 {
127 // cheap to tolerate folders so let's do it.
128 URL url = f.toURI().toURL();
129 if (f.isFile())
130 {// is this necessary anyways?
131 url = new URL("jar:" + url.toString() + "!/");
132 }
133 urls.add(url);
134 }
135 }
136 }
137
138 return new URLClassLoader(urls.toArray(new URL[urls.size()]),parentClassLoader);
139 }
140
141 /**
142 * When we find files typically used for central logging configuration we do
143 * what it takes in this method to do what the user expects. Without
144 * depending too much directly on a particular logging framework.
145 * <p>
146 * We can afford to do some implementation specific code for a logging
147 * framework only in a fragment. <br/>
148 * Trying to configure log4j and logback in here.
149 * </p>
150 * <p>
151 * We recommend that slf4j jars are all placed in the osgi framework. And a
152 * single implementation if possible packaged as an osgi bundle is there.
153 * </p>
154 */
155 protected static void processFilesInResourcesFolder(File jettyHome, Map<String, File> childrenFiles)
156 {
157 for (IFilesInJettyHomeResourcesProcessor processor : registeredFilesInJettyHomeResourcesProcessors)
158 {
159 processor.processFilesInResourcesFolder(jettyHome,childrenFiles);
160 }
161 }
162
163 }