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1
11 package org.eclipse.osgi.framework.internal.core;
12
13 import java.io.IOException  ;
14 import java.net.URL ;
15 import java.security.AccessController ;
16 import java.security.PrivilegedAction ;
17 import java.util.Enumeration ;
18
19 public class SystemPolicy implements IBuddyPolicy {
20
21 private static class ParentClassLoader extends ClassLoader {
22 protected ParentClassLoader() {
23 super(null);
24 }
25 }
26
27 public static final byte BOOT = 0;
28 public static final byte EXT = 1;
29 public static final byte APP = 2;
30
31 private static SystemPolicy[] instances = new SystemPolicy[3];
32
33 private ClassLoader classLoader;
34
35 public static SystemPolicy getInstance(final byte type) {
36 if (instances[type] == null) {
37 instances[type] = new SystemPolicy();
38 instances[type].classLoader = (ClassLoader ) AccessController.doPrivileged(new PrivilegedAction () {
39 public Object run() {
40 return createClassLoader(type);
41 }
42 });
43 }
44 return instances[type];
45 }
46
47 public SystemPolicy() {
48 }
50
51 public SystemPolicy(ClassLoader parent) {
52 classLoader = parent;
53 }
54
55 static ClassLoader createClassLoader(byte type) {
56 switch (type) {
57 case APP :
58 if (ClassLoader.getSystemClassLoader() != null)
59 return ClassLoader.getSystemClassLoader();
60 return new ParentClassLoader();
61
62 case BOOT :
63 return new ParentClassLoader();
64
65 case EXT :
66 if (ClassLoader.getSystemClassLoader() != null)
67 return ClassLoader.getSystemClassLoader().getParent();
68 return new ParentClassLoader();
69 }
70 return null;
71 }
72
73 public Class loadClass(String name) {
74 try {
75 return classLoader.loadClass(name);
76 } catch (ClassNotFoundException e) {
77 return null;
78 }
79 }
80
81 public URL loadResource(String name) {
82 return classLoader.getResource(name);
83 }
84
85 public Enumeration loadResources(String name) {
86 try {
87 return classLoader.getResources(name);
88 } catch (IOException e) {
89 return null;
90 }
91 }
92
93 }
94 |
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