1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/classes/com/sun/tools/javac/util/CloseableURLClassLoader.java Fri Dec 11 14:26:27 2009 -0800
1.3 @@ -0,0 +1,108 @@
1.4 +/*
1.5 + * Copyright 2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Sun designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Sun in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.25 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.26 + * have any questions.
1.27 + */
1.28 +
1.29 +package com.sun.tools.javac.util;
1.30 +
1.31 +import java.io.Closeable;
1.32 +import java.io.IOException;
1.33 +import java.lang.reflect.Field;
1.34 +import java.net.URL;
1.35 +import java.net.URLClassLoader;
1.36 +import java.util.ArrayList;
1.37 +import java.util.jar.JarFile;
1.38 +
1.39 +/**
1.40 + * A URLClassLoader that also implements Closeable.
1.41 + * Reflection is used to access internal data structures in the URLClassLoader,
1.42 + * since no public API exists for this purpose. Therefore this code is somewhat
1.43 + * fragile. Caveat emptor.
1.44 + * @throws Error if the internal data structures are not as expected.
1.45 + *
1.46 + * <p><b>This is NOT part of any API supported by Sun Microsystems. If
1.47 + * you write code that depends on this, you do so at your own risk.
1.48 + * This code and its internal interfaces are subject to change or
1.49 + * deletion without notice.</b>
1.50 + */
1.51 +public class CloseableURLClassLoader
1.52 + extends URLClassLoader implements Closeable {
1.53 + public CloseableURLClassLoader(URL[] urls, ClassLoader parent) throws Error {
1.54 + super(urls, parent);
1.55 + try {
1.56 + getLoaders(); //proactive check that URLClassLoader is as expected
1.57 + } catch (Throwable t) {
1.58 + throw new Error("cannot create CloseableURLClassLoader", t);
1.59 + }
1.60 + }
1.61 +
1.62 + /**
1.63 + * Close any jar files that may have been opened by the class loader.
1.64 + * Reflection is used to access the jar files in the URLClassLoader's
1.65 + * internal data structures.
1.66 + * @throws java.io.IOException if the jar files cannot be found for any
1.67 + * reson, or if closing the jar file itself causes an IOException.
1.68 + */
1.69 + @Override
1.70 + public void close() throws IOException {
1.71 + try {
1.72 + for (Object l: getLoaders()) {
1.73 + if (l.getClass().getName().equals("sun.misc.URLClassPath$JarLoader")) {
1.74 + Field jarField = l.getClass().getDeclaredField("jar");
1.75 + JarFile jar = (JarFile) getField(l, jarField);
1.76 + if (jar != null) {
1.77 + //System.err.println("CloseableURLClassLoader: closing " + jar);
1.78 + jar.close();
1.79 + }
1.80 + }
1.81 + }
1.82 + } catch (Throwable t) {
1.83 + IOException e = new IOException("cannot close class loader");
1.84 + e.initCause(t);
1.85 + throw e;
1.86 + }
1.87 + }
1.88 +
1.89 + private ArrayList<?> getLoaders()
1.90 + throws NoSuchFieldException, IllegalArgumentException, IllegalAccessException
1.91 + {
1.92 + Field ucpField = URLClassLoader.class.getDeclaredField("ucp");
1.93 + Object urlClassPath = getField(this, ucpField);
1.94 + if (urlClassPath == null)
1.95 + throw new AssertionError("urlClassPath not set in URLClassLoader");
1.96 + Field loadersField = urlClassPath.getClass().getDeclaredField("loaders");
1.97 + return (ArrayList<?>) getField(urlClassPath, loadersField);
1.98 + }
1.99 +
1.100 + private Object getField(Object o, Field f)
1.101 + throws IllegalArgumentException, IllegalAccessException {
1.102 + boolean prev = f.isAccessible();
1.103 + try {
1.104 + f.setAccessible(true);
1.105 + return f.get(o);
1.106 + } finally {
1.107 + f.setAccessible(prev);
1.108 + }
1.109 + }
1.110 +
1.111 +}
