Mercurial > jdk8-mips64-public > langtools / file comparison
comparison: src/share/classes/com/sun/tools/javac/file/CloseableURLClassLoader.java
src/share/classes/com/sun/tools/javac/file/CloseableURLClassLoader.java
- changeset 454
- ac5b4c5644ce
- parent 407
- f8be8bf150c3
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| 448:44022ba69c2f | 454:ac5b4c5644ce |
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| 1 /* | |
| 2 * Copyright 2007 Sun Microsystems, Inc. All Rights Reserved. | |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. Sun designates this | |
| 8 * particular file as subject to the "Classpath" exception as provided | |
| 9 * by Sun in the LICENSE file that accompanied this code. | |
| 10 * | |
| 11 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 * accompanied this code). | |
| 16 * | |
| 17 * You should have received a copy of the GNU General Public License version | |
| 18 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 * | |
| 21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 22 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 23 * have any questions. | |
| 24 */ | |
| 25 | |
| 26 package com.sun.tools.javac.file; | |
| 27 | |
| 28 import java.io.Closeable; | |
| 29 import java.io.IOException; | |
| 30 import java.lang.reflect.Field; | |
| 31 import java.net.URL; | |
| 32 import java.net.URLClassLoader; | |
| 33 import java.util.ArrayList; | |
| 34 import java.util.jar.JarFile; | |
| 35 | |
| 36 /** | |
| 37 * A URLClassLoader that also implements Closeable. | |
| 38 * Reflection is used to access internal data structures in the URLClassLoader, | |
| 39 * since no public API exists for this purpose. Therefore this code is somewhat | |
| 40 * fragile. Caveat emptor. | |
| 41 * @throws Error if the internal data structures are not as expected. | |
| 42 * | |
| 43 * <p><b>This is NOT part of any API supported by Sun Microsystems. If | |
| 44 * you write code that depends on this, you do so at your own risk. | |
| 45 * This code and its internal interfaces are subject to change or | |
| 46 * deletion without notice.</b> | |
| 47 */ | |
| 48 class CloseableURLClassLoader | |
| 49 extends URLClassLoader implements Closeable { | |
| 50 CloseableURLClassLoader(URL[] urls, ClassLoader parent) throws Error { | |
| 51 super(urls, parent); | |
| 52 try { | |
| 53 getLoaders(); //proactive check that URLClassLoader is as expected | |
| 54 } catch (Throwable t) { | |
| 55 throw new Error("cannot create CloseableURLClassLoader", t); | |
| 56 } | |
| 57 } | |
| 58 | |
| 59 /** | |
| 60 * Close any jar files that may have been opened by the class loader. | |
| 61 * Reflection is used to access the jar files in the URLClassLoader's | |
| 62 * internal data structures. | |
| 63 * @throws java.io.IOException if the jar files cannot be found for any | |
| 64 * reson, or if closing the jar file itself causes an IOException. | |
| 65 */ | |
| 66 public void close() throws IOException { | |
| 67 try { | |
| 68 for (Object l: getLoaders()) { | |
| 69 if (l.getClass().getName().equals("sun.misc.URLClassPath$JarLoader")) { | |
| 70 Field jarField = l.getClass().getDeclaredField("jar"); | |
| 71 JarFile jar = (JarFile) getField(l, jarField); | |
| 72 if (jar != null) { | |
| 73 //System.err.println("CloseableURLClassLoader: closing " + jar); | |
| 74 jar.close(); | |
| 75 } | |
| 76 } | |
| 77 } | |
| 78 } catch (Throwable t) { | |
| 79 IOException e = new IOException("cannot close class loader"); | |
| 80 e.initCause(t); | |
| 81 throw e; | |
| 82 } | |
| 83 } | |
| 84 | |
| 85 private ArrayList<?> getLoaders() | |
| 86 throws NoSuchFieldException, IllegalArgumentException, IllegalAccessException | |
| 87 { | |
| 88 Field ucpField = URLClassLoader.class.getDeclaredField("ucp"); | |
| 89 Object urlClassPath = getField(this, ucpField); | |
| 90 if (urlClassPath == null) | |
| 91 throw new AssertionError("urlClassPath not set in URLClassLoader"); | |
| 92 Field loadersField = urlClassPath.getClass().getDeclaredField("loaders"); | |
| 93 return (ArrayList<?>) getField(urlClassPath, loadersField); | |
| 94 } | |
| 95 | |
| 96 private Object getField(Object o, Field f) | |
| 97 throws IllegalArgumentException, IllegalAccessException { | |
| 98 boolean prev = f.isAccessible(); | |
| 99 try { | |
| 100 f.setAccessible(true); | |
| 101 return f.get(o); | |
| 102 } finally { | |
| 103 f.setAccessible(prev); | |
| 104 } | |
| 105 } | |
| 106 | |
| 107 } |
