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Java > Open Source Codes > org > jboss > aop > advice > AspectFactoryWithClassLoaderSupport


1 /*
2 * JBoss, Home of Professional Open Source
3 * Copyright 2005, JBoss Inc., and individual contributors as indicated
4 * by the @authors tag. See the copyright.txt in the distribution for a
5 * full listing of individual contributors.
6 *
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This software is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this software; if not, write to the Free
19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21 */
22 package org.jboss.aop.advice;
23
24 import java.lang.ref.WeakReference JavaDoc;
25
26 import org.jboss.aop.AspectManager;
27
28 /**
29  * Helper class to be able to set the classloader needed for loading up the aspects in the aspectfactories
30  * @author <a HREF="kabir.khan@jboss.com">Kabir Khan</a>
31  * @version $Revision: 56777 $
32  */
33 public abstract class AspectFactoryWithClassLoaderSupport implements AspectFactory, AspectFactoryWithClassLoader
34 {
35    private WeakReference JavaDoc loader;
36    
37    /** If a scoped classloader with no parent delegation redefines the class, we need to make sure that that class is pushed on the stack */
38    private ThreadLocal JavaDoc scopedClassLoader = new ThreadLocal JavaDoc();
39    
40    protected AspectFactoryWithClassLoaderSupport()
41    {
42    }
43
44    public void setClassLoader(ClassLoader JavaDoc cl)
45    {
46       this.loader = new WeakReference JavaDoc(cl);
47    }
48    
49    protected ClassLoader JavaDoc getLoader()
50    {
51       ClassLoader JavaDoc scopedClassLoader = peekScopedClassLoader();
52       if (scopedClassLoader != null)
53       {
54          return scopedClassLoader;
55       }
56       if (loader != null)
57       {
58          return (ClassLoader JavaDoc)loader.get();
59       }
60       return null;
61    }
62    
63    public void pushScopedClassLoader(ClassLoader JavaDoc scopedCl)
64    {
65       scopedClassLoader.set(scopedCl);
66    }
67    
68    public void popScopedClassLoader()
69    {
70       scopedClassLoader.set(null);
71    }
72    
73    public ClassLoader JavaDoc peekScopedClassLoader()
74    {
75       return (ClassLoader JavaDoc)scopedClassLoader.get();
76    }
77
78    protected Class JavaDoc loadClass(String JavaDoc name) throws ClassNotFoundException JavaDoc
79    {
80       ClassLoader JavaDoc cl = getLoader();
81       if (cl == null)
82       {
83          ClassLoader JavaDoc tcl = Thread.currentThread().getContextClassLoader();
84          if (AspectManager.verbose) System.out.println("Using context classloader " + tcl + " to load aspect " + name);
85          return tcl.loadClass(name);
86       }
87       else
88       {
89          if (AspectManager.verbose) System.out.println("Using scoped classloader " + cl + " to load aspect " + name);
90          return cl.loadClass(name);
91       }
92    }
93
94 }
95
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