Source code: org/apache/batik/bridge/DocumentJarClassLoader.java
1 /*
2
3 Copyright 2002-2003 The Apache Software Foundation
4
5 Licensed under the Apache License, Version 2.0 (the "License");
6 you may not use this file except in compliance with the License.
7 You may obtain a copy of the License at
8
9 http://www.apache.org/licenses/LICENSE-2.0
10
11 Unless required by applicable law or agreed to in writing, software
12 distributed under the License is distributed on an "AS IS" BASIS,
13 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 See the License for the specific language governing permissions and
15 limitations under the License.
16
17 */
18 package org.apache.batik.bridge;
19
20 import java.net.URL;
21 import java.net.URLClassLoader;
22 import java.security.CodeSource;
23 import java.security.cert.Certificate;
24 import java.security.Permission;
25 import java.security.PermissionCollection;
26 import java.security.Policy;
27 import java.util.Enumeration;
28
29 /**
30 * This <tt>ClassLoader</tt> implementation only grants permission to
31 * connect back to the server from where the document referencing the
32 * jar file was loaded.
33 *
34 * A <tt>URLClassLoader</tt> extension is needed in case the user
35 * allows linked jar files to come from a different origin than
36 * the document referencing them.
37 *
38 * @author <a mailto="vincent.hardy@sun.com">Vincent Hardy</a>
39 * @version $Id: DocumentJarClassLoader.java,v 1.5 2004/10/30 16:54:53 deweese Exp $
40 */
41 public class DocumentJarClassLoader extends URLClassLoader {
42 /**
43 * CodeSource for the Document which referenced the Jar file
44 * @see #getPermissions
45 */
46 protected CodeSource documentCodeSource = null;
47
48 /**
49 * Constructor
50 */
51 public DocumentJarClassLoader(URL jarURL,
52 URL documentURL){
53 super(new URL[]{jarURL});
54
55 if (documentURL != null) {
56 documentCodeSource = new CodeSource
57 (documentURL, (Certificate[])null);
58 }
59 }
60
61 /**
62 * Returns the permissions for the given codesource object.
63 * The implementation of this method first gets the permissions
64 * granted by the policy, and then adds additional permissions
65 * based on the URL of the codesource.
66 * <p>
67 * Then, if the documentURL passed at construction time is
68 * not null, the permissions granted to that URL are added.
69 *
70 * As a result, the jar file code will only be able to
71 * connect to the server which served the document.
72 *
73 * @param codesource the codesource
74 * @return the permissions granted to the codesource
75 */
76 protected PermissionCollection getPermissions(CodeSource codesource)
77 {
78 // First, get the permissions which may be granted
79 // through the policy file(s)
80 Policy p = Policy.getPolicy();
81
82 PermissionCollection pc = null;
83 if (p != null) {
84 pc = p.getPermissions(codesource);
85 }
86
87 // Now, add permissions if the documentCodeSource is not null
88 if (documentCodeSource != null){
89 PermissionCollection urlPC
90 = super.getPermissions(documentCodeSource);
91
92 if (pc != null) {
93 Enumeration items = urlPC.elements();
94 while (items.hasMoreElements()) {
95 pc.add((Permission)(items.nextElement()));
96 }
97 } else {
98 pc = urlPC;
99 }
100 }
101
102 return pc;
103 }
104 }