| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.openjpa.lib.util; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import serp.bytecode.lowlevel.ConstantPoolTable; |
| |
| /** |
| * ClassLoader implementation that allows classes to be temporarily |
| * loaded and then thrown away. Useful for the enhancer to be able |
| * to run against a class without first loading(and thus polluting) |
| * the parent ClassLoader. |
| * |
| * @author Marc Prud'hommeaux |
| */ |
| public class TemporaryClassLoader extends ClassLoader { |
| |
| public TemporaryClassLoader(ClassLoader parent) { |
| super(parent); |
| } |
| |
| @Override |
| public Class loadClass(String name) throws ClassNotFoundException { |
| return loadClass(name, false); |
| } |
| |
| @Override |
| protected Class loadClass(String name, boolean resolve) |
| throws ClassNotFoundException { |
| // see if we've already loaded it |
| Class c = findLoadedClass(name); |
| if (c != null) |
| return c; |
| |
| // bug #283. defer to system if the name is a protected name. |
| // "sun." is required for JDK 1.4, which has an access check for |
| // sun.reflect.GeneratedSerializationConstructorAccessor1 |
| if (name.startsWith("java.") || name.startsWith("javax.") || name.startsWith("jakarta.") |
| || name.startsWith("sun.") || name.startsWith("jdk.")) { |
| return Class.forName(name, resolve, getClass().getClassLoader()); |
| } |
| |
| String resourceName = name.replace('.', '/') + ".class"; |
| InputStream resource = getResourceAsStream(resourceName); |
| if (resource == null) { |
| throw new ClassNotFoundException(name); |
| } |
| |
| ByteArrayOutputStream bout = new ByteArrayOutputStream(); |
| byte[] b = new byte[1024]; |
| try { |
| for (int n = 0; (n = resource.read(b, 0, b.length)) != -1; |
| bout.write(b, 0, n)) |
| ; |
| byte[] classBytes = bout.toByteArray(); |
| // To avoid classloader issues with the JVM (Sun and IBM), we |
| // will not load Enums via the TemporaryClassLoader either. |
| // Reference JIRA Issue OPENJPA-646 for more information. |
| if (isAnnotation(classBytes) || isEnum(classBytes)) { |
| try { |
| Class<?> frameworkClass = Class.forName(name, resolve, |
| getClass().getClassLoader()); |
| return frameworkClass; |
| } catch (ClassNotFoundException e) { |
| // OPENJPA-1121 continue, as it must be a user-defined class |
| } |
| } |
| |
| try { |
| return defineClass(name, classBytes, 0, classBytes.length); |
| } catch (SecurityException e) { |
| // possible prohibited package: defer to the parent |
| return super.loadClass(name, resolve); |
| } |
| } catch (IOException ioe) { |
| // defer to the parent |
| return super.loadClass(name, resolve); |
| } |
| } |
| |
| /** |
| * Fast-parse the given class bytecode to determine if it is an |
| * annotation class. |
| */ |
| private static boolean isAnnotation(byte[] b) { |
| if (JavaVersions.VERSION < 5) |
| return false; |
| int idx = ConstantPoolTable.getEndIndex(b); |
| int access = ConstantPoolTable.readUnsignedShort(b, idx); |
| return (access & 0x2000) != 0; // access constant for annotation type |
| } |
| |
| /** |
| * Fast-parse the given class bytecode to determine if it is an |
| * enum class. |
| */ |
| private static boolean isEnum(byte[] b) { |
| if (JavaVersions.VERSION < 5) |
| return false; |
| int idx = ConstantPoolTable.getEndIndex(b); |
| int access = ConstantPoolTable.readUnsignedShort(b, idx); |
| return (access & 0x4000) != 0; // access constant for enum type |
| } |
| } |