| import java.io.BufferedOutputStream; |
| import java.io.FileNotFoundException; |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.net.URL; |
| import java.net.URLClassLoader; |
| import java.util.jar.JarEntry; |
| import java.util.jar.JarOutputStream; |
| |
| /* |
| * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| /** |
| * A ByteClassLoader is used to define classes from collections of bytes, as |
| * well as loading classes in the usual way. It includes options to write the |
| * classes to files in a jar, or to read the classes from jars in a later or |
| * debugging run. |
| * |
| * If Boolean property byteclassloader.verbose is true, be chatty about jar |
| * file operations. |
| * |
| */ |
| public class ByteClassLoader extends URLClassLoader { |
| |
| final static boolean verbose |
| = Boolean.getBoolean("byteclassloader.verbose"); |
| |
| final boolean read; |
| final JarOutputStream jos; |
| final String jar_name; |
| |
| /** |
| * Make a new ByteClassLoader. |
| * |
| * @param jar_name Basename of jar file to be read/written by this classloader. |
| * @param read If true, read classes from jar file instead of from parameter. |
| * @param write If true, write classes to jar files for offline study/use. |
| * |
| * @throws FileNotFoundException |
| * @throws IOException |
| */ |
| public ByteClassLoader(String jar_name, boolean read, boolean write) |
| throws FileNotFoundException, IOException { |
| super(read |
| ? new URL[]{new URL("file:" + jar_name + ".jar")} |
| : new URL[0]); |
| this.read = read; |
| this.jar_name = jar_name; |
| this.jos = write |
| ? new JarOutputStream( |
| new BufferedOutputStream( |
| new FileOutputStream(jar_name + ".jar"))) : null; |
| if (read && write) { |
| throw new Error("At most one of read and write may be true."); |
| } |
| } |
| |
| private static void writeJarredFile(JarOutputStream jos, String file, String suffix, byte[] bytes) { |
| String fileName = file.replace(".", "/") + "." + suffix; |
| JarEntry ze = new JarEntry(fileName); |
| try { |
| ze.setSize(bytes.length); |
| jos.putNextEntry(ze); |
| jos.write(bytes); |
| jos.closeEntry(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| /** |
| * (pre)load class name using classData for the definition. |
| * |
| * @param name |
| * @param classData |
| * @return |
| */ |
| public Class<?> loadBytes(String name, byte[] classData) throws ClassNotFoundException { |
| if (jos != null) { |
| if (verbose) { |
| System.out.println("ByteClassLoader: writing " + name); |
| } |
| writeJarredFile(jos, name, "class", classData); |
| } |
| |
| Class<?> clazz = null; |
| if (read) { |
| if (verbose) { |
| System.out.println("ByteClassLoader: reading " + name + " from " + jar_name); |
| } |
| clazz = loadClass(name); |
| } else { |
| clazz = defineClass(name, classData, 0, classData.length); |
| resolveClass(clazz); |
| } |
| return clazz; |
| } |
| |
| public void close() { |
| if (jos != null) { |
| try { |
| if (verbose) { |
| System.out.println("ByteClassLoader: closing " + jar_name); |
| } |
| jos.close(); |
| } catch (IOException ex) { |
| } |
| } |
| } |
| } |