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Java > Open Source Codes > org > jboss > axis > utils > JWSClassLoader


1 /*
2  * The Apache Software License, Version 1.1
3  *
4  *
5  * Copyright (c) 2002-2003 The Apache Software Foundation. All rights
6  * reserved.
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9  * modification, are permitted provided that the following conditions
10  * are met:
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13  * notice, this list of conditions and the following disclaimer.
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15  * 2. Redistributions in binary form must reproduce the above copyright
16  * notice, this list of conditions and the following disclaimer in
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20  * 3. The end-user documentation included with the redistribution,
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24  * Alternately, this acknowledgment may appear in the software itself,
25  * if and wherever such third-party acknowledgments normally appear.
26  *
27  * 4. The names "Axis" and "Apache Software Foundation" must
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29  * software without prior written permission. For written
30  * permission, please contact apache@apache.org.
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53  * <http://www.apache.org/>.
54  */
55 package org.jboss.axis.utils;
56
57 import java.io.ByteArrayOutputStream JavaDoc;
58 import java.io.FileInputStream JavaDoc;
59 import java.io.FileNotFoundException JavaDoc;
60 import java.io.IOException JavaDoc;
61 import java.io.InputStream JavaDoc;
62
63 /**
64  * Class loader for JWS files. There is one of these per JWS class, and
65  * we keep a static Hashtable of them, indexed by class name. When we want
66  * to reload a JWS, we replace the ClassLoader for that class and let the
67  * old one get GC'ed.
68  *
69  * @author Glen Daniels (gdaniels@apache.org)
70  * @author Doug Davis (dug@us.ibm.com)
71  */
72 public class JWSClassLoader extends ClassLoader JavaDoc
73 {
74
75    private String JavaDoc classFile = null;
76    private String JavaDoc name = null;
77
78    /**
79     * Construct a JWSClassLoader with a class name, a parent ClassLoader,
80     * and a filename of a .class file containing the bytecode for the class.
81     * The constructor will load the bytecode, define the class, and register
82     * this JWSClassLoader in the static registry.
83     *
84     * @param name the name of the class which will be created/loaded
85     * @param cl the parent ClassLoader
86     * @param classFile filename of the .class file
87     * @throws FileNotFoundException
88     * @throws IOException
89     */
90    public JWSClassLoader(String JavaDoc name, ClassLoader JavaDoc cl, String JavaDoc classFile)
91            throws FileNotFoundException JavaDoc, IOException JavaDoc
92    {
93       super(cl);
94
95       this.name = name + ".class";
96       this.classFile = classFile;
97
98       FileInputStream JavaDoc fis = new FileInputStream JavaDoc(classFile);
99       ByteArrayOutputStream JavaDoc baos = new ByteArrayOutputStream JavaDoc();
100       byte buf[] = new byte[1024];
101       for (int i = 0; (i = fis.read(buf)) != -1;)
102          baos.write(buf, 0, i);
103       fis.close();
104       baos.close();
105
106       /* Create a new Class object from it */
107       /*************************************/
108       byte[] data = baos.toByteArray();
109       defineClass(name, data, 0, data.length);
110
111       ClassUtils.setClassLoader(name, this);
112    }
113
114    /**
115     * Overloaded getResourceAsStream() so we can be sure to return the
116     * correct class file regardless of where it might live on our hard
117     * drive.
118     *
119     * @param resourceName the resource to load (should be "classname.class")
120     * @return an InputStream of the class bytes, or null
121     */
122    public InputStream JavaDoc getResourceAsStream(String JavaDoc resourceName)
123    {
124       try
125       {
126          if (resourceName.equals(name))
127             return new FileInputStream JavaDoc(classFile);
128       }
129       catch (FileNotFoundException JavaDoc e)
130       {
131          // Fall through, return null.
132 }
133       return null;
134    }
135 }
136
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