1 /*
2 * Grapht, an open source dependency injector.
3 * Copyright 2014-2015 various contributors (see CONTRIBUTORS.txt)
4 * Copyright 2010-2014 Regents of the University of Minnesota
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as
8 * published by the Free Software Foundation; either version 2.1 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
14 * details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc., 51
18 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 */
20 package org.grouplens.grapht.util;
21
22 /**
23 * A class loader context, used to restore the state from {@link ClassLoaders#pushContext(ClassLoader)}.
24 *
25 * @since 0.8.1
26 * @author <a href="http://www.grouplens.org">GroupLens Research</a>
27 */
28 public class ClassLoaderContext {
29 private final Thread thread;
30 private final ClassLoader original;
31 private boolean popped = false;
32
33 ClassLoaderContext(Thread th, ClassLoader orig) {
34 thread = th;
35 original = orig;
36 }
37
38 /**
39 * Restore the original class loader before this context was entered.
40 * @throws IllegalStateException if the context was already popped.
41 */
42 public void pop() {
43 if (popped) {
44 throw new IllegalStateException("loader context already popped");
45 }
46 thread.setContextClassLoader(original);
47 popped = true;
48 }
49 }