001// Copyright 2004, 2005 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.hivemind.service.impl; 016 017import java.util.HashSet; 018import java.util.Set; 019 020import javassist.CannotCompileException; 021import javassist.ClassPath; 022import javassist.ClassPool; 023import javassist.CtClass; 024import javassist.LoaderClassPath; 025 026/** 027 * Used to ensure that {@link javassist.ClassPool#appendClassPath(javassist.ClassPath)} is invoked 028 * with a synchronized lock. Additionally, wraps around a shared 029 * {@link org.apache.hivemind.service.impl.ClassFactoryClassLoader}. 030 * 031 * @author Howard Lewis Ship 032 */ 033public class HiveMindClassPool extends ClassPool 034{ 035 private ClassFactoryClassLoader _loader = new ClassFactoryClassLoader(); 036 037 /** 038 * Used to identify which class loaders have already been integrated into the pool. 039 */ 040 private Set _loaders = new HashSet(); 041 042 public HiveMindClassPool() 043 { 044 super(null); 045 046 appendClassLoader(Thread.currentThread().getContextClassLoader()); 047 } 048 049 /** 050 * Convienience method for adding to the ClassPath for a particular class loader. 051 */ 052 public synchronized void appendClassLoader(ClassLoader loader) 053 { 054 if (loader == null || loader == _loader || _loaders.contains(loader)) 055 return; 056 057 _loader.addDelegateLoader(loader); 058 059 ClassPath path = new LoaderClassPath(loader); 060 061 appendClassPath(path); 062 063 _loaders.add(loader); 064 } 065 066 /** 067 * Invoked to convert an fabricated class into a real class. The new classes' class loader will 068 * be the delegating ClassFactoryClassLoader, which has visibility to all class loaders for all 069 * modules. 070 * 071 * @since 1.1 072 */ 073 public Class toClass(CtClass ctClass) throws CannotCompileException 074 { 075 return ctClass.toClass(_loader); 076 } 077}