1 /*
2  * Copyright (c) 2012, 2013, 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.
8  *
9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 package separate;
25 
26 import java.util.HashMap;
27 import java.io.File;
28 import java.io.FileInputStream;
29 import java.io.IOException;
30 
31 class DirectedClassLoader extends ClassLoader {
32 
33     private HashMap<String,File> loadLocations;
34     private File defaultLocation;
35     private ClassFilePreprocessor[] preprocessors;
36 
DirectedClassLoader( HashMap<String,File> locations, File fallback, ClassFilePreprocessor ... preprocessors)37     public DirectedClassLoader(
38             HashMap<String,File> locations, File fallback,
39             ClassFilePreprocessor ... preprocessors) {
40         loadLocations = new HashMap<>(locations);
41         defaultLocation = fallback;
42         this.preprocessors = preprocessors;
43     }
44 
DirectedClassLoader( File fallback, ClassFilePreprocessor ... preprocessors)45     public DirectedClassLoader(
46             File fallback, ClassFilePreprocessor ... preprocessors) {
47         loadLocations = new HashMap<>();
48         defaultLocation = fallback;
49         this.preprocessors = preprocessors;
50     }
51 
DirectedClassLoader(ClassFilePreprocessor .... preprocessors)52     public DirectedClassLoader(ClassFilePreprocessor ... preprocessors) {
53         this((File)null, preprocessors);
54     }
55 
setDefaultLocation(File dir)56     public void setDefaultLocation(File dir) { this.defaultLocation = dir; }
setLocationFor(String name, File dir)57     public void setLocationFor(String name, File dir) {
58         loadLocations.put(name, dir);
59     }
60 
61     @Override
findClass(String name)62     protected Class<?> findClass(String name) {
63         String path = name.replace(".", File.separator) + ".class";
64 
65         File location = loadLocations.get(name);
66         if (location == null || !(new File(location, path)).exists()) {
67             File def = new File(defaultLocation, path);
68             if (def.exists()) {
69                 return defineFrom(name, new File(location, path));
70             }
71         } else {
72             return defineFrom(name, new File(location, path));
73         }
74         return null;
75     }
76 
defineFrom(String name, File file)77     private Class<?> defineFrom(String name, File file) {
78         FileInputStream fis = null;
79         try {
80             try {
81                 fis = new FileInputStream(file);
82                 byte[] bytes = new byte[fis.available()];
83                 int read = fis.read(bytes);
84                 if (read != bytes.length) {
85                     return null;
86                 }
87                 if (preprocessors != null) {
88                     for (ClassFilePreprocessor cfp : preprocessors) {
89                         bytes = cfp.preprocess(name, bytes);
90                     }
91                  }
92                 return defineClass(name, bytes, 0, bytes.length);
93             } finally {
94                 fis.close();
95             }
96         } catch (IOException e) {}
97         return null;
98     }
99 }
100