DirectoryLoader.java revision 608:7e06bf1dcb09 
1/*
2 * Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26/*
27 * Licensed Materials - Property of IBM
28 * RMI-IIOP v1.0
29 * Copyright IBM Corp. 1998 1999  All Rights Reserved
30 *
31 */
32
33package sun.rmi.rmic.iiop;
34
35import java.util.Hashtable;
36import java.io.File;
37import java.io.FileInputStream;
38
39/**
40 * DirectoryLoader is a simple ClassLoader which loads from a specified
41 * file system directory.
42 * @author Bryan Atsatt
43 */
44
45public class DirectoryLoader extends ClassLoader {
46
47    private Hashtable cache;
48    private File root;
49
50    /**
51     * Constructor.
52     */
53    public DirectoryLoader (File rootDir) {
54        cache = new Hashtable();
55        if (rootDir == null || !rootDir.isDirectory()) {
56            throw new IllegalArgumentException();
57        }
58        root = rootDir;
59    }
60
61    private DirectoryLoader () {}
62
63    /**
64     * Convenience version of loadClass which sets 'resolve' == true.
65     */
66    public Class loadClass(String className) throws ClassNotFoundException {
67        return loadClass(className, true);
68    }
69
70    /**
71     * This is the required version of loadClass which is called
72     * both from loadClass above and from the internal function
73     * FindClassFromClass.
74     */
75    public synchronized Class loadClass(String className, boolean resolve)
76        throws ClassNotFoundException {
77        Class result;
78        byte  classData[];
79
80        // Do we already have it in the cache?
81
82        result = (Class) cache.get(className);
83
84        if (result == null) {
85
86            // Nope, can we get if from the system class loader?
87
88            try {
89
90                result = super.findSystemClass(className);
91
92            } catch (ClassNotFoundException e) {
93
94                // No, so try loading it...
95
96                classData = getClassFileData(className);
97
98                if (classData == null) {
99                    throw new ClassNotFoundException();
100                }
101
102                // Parse the class file data...
103
104                result = defineClass(classData, 0, classData.length);
105
106                if (result == null) {
107                    throw new ClassFormatError();
108                }
109
110                // Resolve it...
111
112                if (resolve) resolveClass(result);
113
114                // Add to cache...
115
116                cache.put(className, result);
117            }
118        }
119
120        return result;
121    }
122
123    /**
124     * Reurn a byte array containing the contents of the class file.  Returns null
125     * if an exception occurs.
126     */
127    private byte[] getClassFileData (String className) {
128
129        byte result[] = null;
130        FileInputStream stream = null;
131
132        // Get the file...
133
134        File classFile = new File(root,className.replace('.',File.separatorChar) + ".class");
135
136        // Now get the bits...
137
138        try {
139            stream = new FileInputStream(classFile);
140            result = new byte[stream.available()];
141            stream.read(result);
142        } catch(ThreadDeath death) {
143            throw death;
144        } catch (Throwable e) {
145        }
146
147        finally {
148            if (stream != null) {
149                try {
150                    stream.close();
151                } catch(ThreadDeath death) {
152                    throw death;
153                } catch (Throwable e) {
154                }
155            }
156        }
157
158        return result;
159    }
160}
161