1/* 2 * Copyright (c) 2013, Oracle and/or its affiliates. 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24package compiler.jsr292.methodHandleExceptions; 25 26import java.io.BufferedOutputStream; 27import java.io.FileNotFoundException; 28import java.io.FileOutputStream; 29import java.io.IOException; 30import java.net.URL; 31import java.net.URLClassLoader; 32import java.util.jar.JarEntry; 33import java.util.jar.JarOutputStream; 34 35/** 36 * A ByteClassLoader is used to define classes from collections of bytes, as 37 * well as loading classes in the usual way. It includes options to write the 38 * classes to files in a jar, or to read the classes from jars in a later or 39 * debugging run. 40 * 41 * If Boolean property byteclassloader.verbose is true, be chatty about jar 42 * file operations. 43 * 44 */ 45public class ByteClassLoader extends URLClassLoader { 46 47 final static boolean verbose 48 = Boolean.getBoolean("byteclassloader.verbose"); 49 50 final boolean read; 51 final JarOutputStream jos; 52 final String jar_name; 53 54 /** 55 * Make a new ByteClassLoader. 56 * 57 * @param jar_name Basename of jar file to be read/written by this classloader. 58 * @param read If true, read classes from jar file instead of from parameter. 59 * @param write If true, write classes to jar files for offline study/use. 60 * 61 * @throws FileNotFoundException 62 * @throws IOException 63 */ 64 public ByteClassLoader(String jar_name, boolean read, boolean write) 65 throws FileNotFoundException, IOException { 66 super(read 67 ? new URL[]{new URL("file:" + jar_name + ".jar")} 68 : new URL[0]); 69 this.read = read; 70 this.jar_name = jar_name; 71 this.jos = write 72 ? new JarOutputStream( 73 new BufferedOutputStream( 74 new FileOutputStream(jar_name + ".jar"))) : null; 75 if (read && write) { 76 throw new Error("At most one of read and write may be true."); 77 } 78 } 79 80 private static void writeJarredFile(JarOutputStream jos, String file, String suffix, byte[] bytes) { 81 String fileName = file.replace(".", "/") + "." + suffix; 82 JarEntry ze = new JarEntry(fileName); 83 try { 84 ze.setSize(bytes.length); 85 jos.putNextEntry(ze); 86 jos.write(bytes); 87 jos.closeEntry(); 88 } catch (IOException e) { 89 throw new RuntimeException(e); 90 } 91 } 92 93 /** 94 * (pre)load class name using classData for the definition. 95 * 96 * @param name 97 * @param classData 98 * @return 99 */ 100 public Class<?> loadBytes(String name, byte[] classData) throws ClassNotFoundException { 101 if (jos != null) { 102 if (verbose) { 103 System.out.println("ByteClassLoader: writing " + name); 104 } 105 writeJarredFile(jos, name, "class", classData); 106 } 107 108 Class<?> clazz = null; 109 if (read) { 110 if (verbose) { 111 System.out.println("ByteClassLoader: reading " + name + " from " + jar_name); 112 } 113 clazz = loadClass(name); 114 } else { 115 clazz = defineClass(name, classData, 0, classData.length); 116 resolveClass(clazz); 117 } 118 return clazz; 119 } 120 121 public void close() { 122 if (jos != null) { 123 try { 124 if (verbose) { 125 System.out.println("ByteClassLoader: closing " + jar_name); 126 } 127 jos.close(); 128 } catch (IOException ex) { 129 } 130 } 131 } 132} 133