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 */ 24 25 package compiler.jsr292.methodHandleExceptions; 26 27 import java.io.BufferedOutputStream; 28 import java.io.FileNotFoundException; 29 import java.io.FileOutputStream; 30 import java.io.IOException; 31 import java.net.URL; 32 import java.net.URLClassLoader; 33 import java.util.jar.JarEntry; 34 import java.util.jar.JarOutputStream; 35 36 /** 37 * A ByteClassLoader is used to define classes from collections of bytes, as 38 * well as loading classes in the usual way. It includes options to write the 39 * classes to files in a jar, or to read the classes from jars in a later or 40 * debugging run. 41 * 42 * If Boolean property byteclassloader.verbose is true, be chatty about jar 43 * file operations. 44 * 45 */ 46 public class ByteClassLoader extends URLClassLoader { 47 48 final static boolean verbose 49 = Boolean.getBoolean("byteclassloader.verbose"); 50 51 final boolean read; 52 final JarOutputStream jos; 53 final String jar_name; 54 55 /** 56 * Make a new ByteClassLoader. 57 * 58 * @param jar_name Basename of jar file to be read/written by this classloader. 59 * @param read If true, read classes from jar file instead of from parameter. 60 * @param write If true, write classes to jar files for offline study/use. 61 * 62 * @throws FileNotFoundException 63 * @throws IOException 64 */ 65 public ByteClassLoader(String jar_name, boolean read, boolean write) 66 throws FileNotFoundException, IOException { 67 super(read 68 ? new URL[]{new URL("file:" + jar_name + ".jar")} 69 : new URL[0]); 70 this.read = read; 71 this.jar_name = jar_name; 72 this.jos = write 73 ? new JarOutputStream( 74 new BufferedOutputStream( 75 new FileOutputStream(jar_name + ".jar"))) : null; 76 if (read && write) { 77 throw new Error("At most one of read and write may be true."); 78 } 79 } 80 81 private static void writeJarredFile(JarOutputStream jos, String file, String suffix, byte[] bytes) { 82 String fileName = file.replace(".", "/") + "." + suffix; 83 JarEntry ze = new JarEntry(fileName); 84 try { 85 ze.setSize(bytes.length); 86 jos.putNextEntry(ze); 87 jos.write(bytes); 88 jos.closeEntry(); 89 } catch (IOException e) { 90 throw new RuntimeException(e); 91 } 92 } 93 94 /** 95 * (pre)load class name using classData for the definition. 96 * 97 * @param name 98 * @param classData 99 * @return 100 */ 101 public Class<?> loadBytes(String name, byte[] classData) throws ClassNotFoundException { 102 if (jos != null) { 103 if (verbose) { 104 System.out.println("ByteClassLoader: writing " + name); 105 } 106 writeJarredFile(jos, name, "class", classData); 107 } 108 109 Class<?> clazz = null; 110 if (read) { 111 if (verbose) { 112 System.out.println("ByteClassLoader: reading " + name + " from " + jar_name); 113 } 114 clazz = loadClass(name); 115 } else { 116 clazz = defineClass(name, classData, 0, classData.length); 117 resolveClass(clazz); 118 } 119 return clazz; 120 } 121 122 public void close() { 123 if (jos != null) { 124 try { 125 if (verbose) { 126 System.out.println("ByteClassLoader: closing " + jar_name); 127 } 128 jos.close(); 129 } catch (IOException ex) { 130 } 131 } 132 } 133 }