1 /*
2 * Copyright (c) 2017, 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 import java.util.*;
25 import java.io.*;
26
27 public class PreemptingClassLoader extends ClassLoader {
28
29 private final Set<String> names = new HashSet<>();
30
31 public PreemptingClassLoader(String... names) {
32 for (String n : names) this.names.add(n);
33 }
34
35 protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
36 if (!names.contains(name)) return super.loadClass(name, resolve);
37 Class<?> result = findLoadedClass(name);
38 if (result == null) {
39 String filename = name.replace('.', '/') + ".class";
40 try (InputStream data = getResourceAsStream(filename)) {
41 if (data == null) throw new ClassNotFoundException();
42 try (ByteArrayOutputStream buffer = new ByteArrayOutputStream()) {
43 int b;
44 do {
45 b = data.read();
46 if (b >= 0) buffer.write(b);
47 } while (b >= 0);
48 byte[] bytes = buffer.toByteArray();
49 result = defineClass(name, bytes, 0, bytes.length);
50 }
51 } catch (IOException e) {
52 throw new ClassNotFoundException("Error reading class file", e);
53 }
54 }
55 if (resolve) resolveClass(result);
56 return result;
57 }
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1 /*
2 * Copyright (c) 2017, 2018, 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 import java.util.*;
25 import java.io.*;
26
27 public class PreemptingClassLoader extends ClassLoader {
28
29 private final Set<String> names = new HashSet<>();
30 boolean checkLoaded = true;
31
32 public PreemptingClassLoader(String... names) {
33 for (String n : names) this.names.add(n);
34 }
35
36 public PreemptingClassLoader(String name, String[] names) {
37 super(name, ClassLoader.getSystemClassLoader());
38 for (String n : names) this.names.add(n);
39 }
40
41 public PreemptingClassLoader(String name, String[] names, boolean cL) {
42 super(name, ClassLoader.getSystemClassLoader());
43 for (String n : names) this.names.add(n);
44 checkLoaded = cL;
45 }
46
47 protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
48 if (!names.contains(name)) return super.loadClass(name, resolve);
49 Class<?> result = checkLoaded ? findLoadedClass(name) : null;
50 if (result == null) {
51 String filename = name.replace('.', '/') + ".class";
52 try (InputStream data = getResourceAsStream(filename)) {
53 if (data == null) throw new ClassNotFoundException();
54 try (ByteArrayOutputStream buffer = new ByteArrayOutputStream()) {
55 int b;
56 do {
57 b = data.read();
58 if (b >= 0) buffer.write(b);
59 } while (b >= 0);
60 byte[] bytes = buffer.toByteArray();
61 result = defineClass(name, bytes, 0, bytes.length);
62 }
63 } catch (IOException e) {
64 throw new ClassNotFoundException("Error reading class file", e);
65 }
66 }
67 if (resolve) resolveClass(result);
68 return result;
69 }
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