1 /**
2 * This file Copyright (c) 2010-2010 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.module.groovy.support.classes;
35
36 import groovy.lang.GroovyClassLoader;
37 import groovy.lang.GroovyObject;
38 import info.magnolia.module.groovy.support.HierarchyManagerProvider;
39 import info.magnolia.objectfactory.ClassFactory;
40 import info.magnolia.objectfactory.DefaultClassFactory;
41
42 import org.codehaus.groovy.control.CompilationFailedException;
43
44
45 /**
46 * A {@link info.magnolia.objectfactory.ClassFactory} which attempts to load classes using a
47 * {@link groovy.lang.GroovyClassLoader} if they were not found using a delegate (which is a
48 * {@link info.magnolia.objectfactory.DefaultClassFactory} by default).
49 *
50 * A little bit of background:
51 * When loading classes via the GroovyClassLoader, we loose control on where classes
52 * are loaded from. The GroovyClassLoader will always first attempt to load any given
53 * class via its parent*. This is actually the expected behaviour from regular ClassLoader
54 * implementations. As long as we first try loading our classes via the DefaultClassFactory,
55 * we're fine, we keep control of the order in which ClassLoaders are poked for classes.
56 * By default, the GroovyClassLoader uses the current thread's ContextClassLoader, while
57 * we first use the caller's ClassLoader, *then* the thread's.
58 * Any class/script loaded via the GroovyClassLoader and using classes that haven't been
59 * loaded yet will thus see those classes loaded via the current thread's ContextClassLoader.
60 * If this were to become an issue, we'd probably need to create something along the lines of
61 * a ClassFactoryAwareClassLoader, and give that as a parent to the GroovyClassLoader.
62 *
63 * @author gjoseph
64 * @version $Revision: $ ($Author: $)
65 */
66 public class GroovyClassFactory implements ClassFactory {
67 private final static org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(GroovyClassFactory.class);
68
69 private final ClassFactory delegate;
70 private final GroovyClassLoader gcl;
71
72 public GroovyClassFactory() {
73 // Using the SystemContext to load classes of the repository, by default.
74 // Since the forName() method will attempt to load any class via the DefaultClassFactory *first*,
75 // we should hopefully have a SystemContext implementation ready by the time we need to access the repository.
76 // (and the repository should be ready by then too)
77 this(new DefaultClassFactory(), new HierarchyManagerProvider.SystemContextHierarchyManagerProvider());
78 }
79
80 public GroovyClassFactory(ClassFactory delegate, HierarchyManagerProvider hmp) {
81 if (hmp == null || delegate == null) {
82 throw new IllegalArgumentException("Delegate ClassFactory and HierarchyManagerProvider can not be null");
83 }
84
85 this.delegate = delegate;
86 this.gcl = new MgnlGroovyClassLoader(hmp);
87 }
88
89 public <C> Class<C> forName(String className) throws ClassNotFoundException {
90 try {
91 return delegate.forName(className);
92 } catch (ClassNotFoundException cnfe) {
93 try {
94 return gcl.loadClass(className, true, false);
95 } catch (CompilationFailedException compilationException) {
96 // TODO - would be nice to get the precise location of the source script ...
97 log.error("Could not compile {} with Groovy:\n{}", className, compilationException.getMessage());
98 throw new ClassNotFoundException("Could not compile " + className + " with Groovy", compilationException);
99 }
100 }
101 }
102
103 public <T> T newInstance(Class<T> c, Object... objects) {
104 final Class<T> klass = recompileClassIfNeeded(c);
105 return delegate.newInstance(klass, objects);
106 }
107
108 public <T> T newInstance(Class<T> c, Class<?>[] argTypes, Object... params) {
109 final Class<T> klass = recompileClassIfNeeded(c);
110 return delegate.newInstance(klass, argTypes, params);
111 }
112
113 // TODO - shouldn't this move to the ResourceLoader ?
114 private <T> Class<T> recompileClassIfNeeded(Class<T> c) {
115 Class<T> klass = c;
116 if (GroovyObject.class.isAssignableFrom(c)) {
117 log.debug("{} is a Groovy object, so check if a newer source is available", c.getName());
118 try {
119 klass = gcl.loadClass(c.getName(), true, false);
120 }
121 catch (ClassNotFoundException e) {
122 log.warn(e.getMessage());
123 klass = c;
124 }
125 }
126 return klass;
127 }
128 }