| /* |
| * Copyright (c) 2007, 2018, 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. |
| */ |
| |
| package nsk.share.classload; |
| |
| import java.io.*; |
| import java.util.*; |
| import nsk.share.*; |
| |
| /** |
| * Classloader that generates classes on the fly. |
| * |
| * This classloader can load classes with name starting with 'Class'. |
| * It will use nsk.share.classload.TemplateClass as template and will |
| * replace class name in the bytecode of template class. It can be used |
| * for example to detect memory leaks in class loading or to quickly |
| * fill PermGen. |
| */ |
| public class GeneratingClassLoader extends ClassLoader { |
| public static final String DEFAULT_CLASSNAME = TemplateClass.class.getName(); |
| public static final String PREFIX = "Class"; |
| |
| private final String [] classPath; |
| private byte[] bytecode; |
| private int[] offsets; |
| private final String encoding = "UTF8"; |
| private final String templateClassName; |
| private final byte[] templateClassNameBytes; |
| |
| /** |
| * Create generating class loader that will use class file |
| * for given class from classpath as template. |
| */ |
| public GeneratingClassLoader(String templateClassName) { |
| this.templateClassName = templateClassName; |
| classPath = System.getProperty("java.class.path").split(File.pathSeparator); |
| try { |
| templateClassNameBytes = templateClassName.getBytes(encoding); |
| } catch (UnsupportedEncodingException e) { |
| throw new TestBug(e); |
| } |
| } |
| |
| /** |
| * Create generating class loader that will use class file |
| * for nsk.share.classload.TemplateClass as template. |
| */ |
| public GeneratingClassLoader() { |
| this("nsk.share.classload.TemplateClass"); |
| } |
| |
| public int getNameLength() { |
| return templateClassName.length(); |
| } |
| |
| public String getPrefix() { |
| return PREFIX; |
| } |
| |
| public String getClassName(int number) { |
| StringBuffer sb = new StringBuffer(); |
| sb.append(PREFIX); |
| sb.append(number); |
| int n = templateClassName.length() - sb.length(); |
| for (int i = 0; i < n; ++i) |
| sb.append("_"); |
| return sb.toString(); |
| } |
| |
| public synchronized Class loadClass(String name) throws ClassNotFoundException { |
| return loadClass(name, false); |
| } |
| |
| public synchronized Class loadClass(String name, boolean resolve) |
| throws ClassNotFoundException { |
| Class c = findLoadedClass(name); |
| if (c != null) |
| return c; |
| if (!name.startsWith(PREFIX)) |
| return super.loadClass(name, resolve); |
| if (name.length() != templateClassName.length()) |
| throw new ClassNotFoundException("Only can load classes with name.length() = " + getNameLength() + " got: '" + name + "' length: " + name.length()); |
| byte[] bytecode = getPatchedByteCode(name); |
| c = defineClass(name, bytecode, 0, bytecode.length); |
| if (resolve) |
| resolveClass(c); |
| return c; |
| } |
| |
| private byte[] getPatchedByteCode(String name) throws ClassNotFoundException { |
| try { |
| byte[] bytecode = getByteCode(); |
| String fname = name.replace(".", File.separator); |
| byte[] replaceBytes = fname.getBytes(encoding); |
| for (int offset : offsets) { |
| for (int i = 0; i < replaceBytes.length; ++i) |
| bytecode[offset + i] = replaceBytes[i]; |
| } |
| return bytecode; |
| } catch (UnsupportedEncodingException e) { |
| throw new TestBug(e); |
| } catch (IOException e) { |
| throw new TestBug(e); |
| } |
| } |
| |
| private byte[] getByteCode() throws ClassNotFoundException { |
| if (bytecode == null) |
| readByteCode(); |
| if (offsets == null) { |
| getOffsets(bytecode); |
| if (offsets == null) |
| throw new TestBug("Class name not found in template class file"); |
| } |
| return (byte[]) bytecode.clone(); |
| } |
| |
| private void readByteCode() throws ClassNotFoundException { |
| String fname = templateClassName.replace(".", File.separator) + ".class"; |
| File target = null; |
| for (int i = 0; i < classPath.length; ++i) { |
| target = new File(classPath[i] + File.separator + fname); |
| if (target.exists()) |
| break; |
| } |
| |
| if (target == null || !target.exists()) |
| throw new ClassNotFoundException("File not found: " + target); |
| try { |
| bytecode = FileUtils.readFile(target); |
| } catch (IOException e) { |
| throw new ClassNotFoundException(templateClassName, e); |
| } |
| } |
| |
| private void getOffsets(byte[] bytecode) { |
| List<Integer> offsets = new ArrayList<Integer>(); |
| if (this.offsets == null) { |
| String pname = templateClassName.replace(".", "/"); |
| try { |
| byte[] pnameb = pname.getBytes(encoding); |
| int i = 0; |
| while (true) { |
| while (i < bytecode.length) { |
| int j = 0; |
| while (j < pnameb.length && bytecode[i + j] == pnameb[j]) |
| ++j; |
| if (j == pnameb.length) |
| break; |
| i++; |
| } |
| if (i == bytecode.length) |
| break; |
| offsets.add(new Integer(i)); |
| i++; |
| } |
| } catch (UnsupportedEncodingException e) { |
| throw new TestBug(e); |
| } |
| this.offsets = new int[offsets.size()]; |
| for (int i = 0; i < offsets.size(); ++i) |
| this.offsets[i] = offsets.get(i).intValue(); |
| } |
| } |
| } |