1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. 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 package org.apache.commons.vfs2.util;
18
19 /**
20 * Factory to create an instance of a Cryptor.
21 *
22 * @since 2.0
23 */
24 public final class CryptorFactory {
25
26 /**
27 * The System property name to identify the Cryptor class to be used.
28 */
29 public static final String CRYPTOR_CLASS = "org.apache.commons.vfs2.cryptor";
30
31 private static Cryptor instance;
32
33 /**
34 * Prevent instantiation of the class.
35 */
36 private CryptorFactory() {
37
38 }
39
40 /**
41 * Allows the Cryptor class to be set programmatically.
42 *
43 * @param cryptor The Cryptor.
44 */
45 public static synchronized void setCryptor(final Cryptor cryptor) {
46 instance = cryptor;
47 }
48
49 /**
50 * Return the Cryptor. If one has not been previously set, create it. The Cryptor class can be set by setting the
51 * "org.apache.commons.vfs2.cryptor" System property to the name of the Cryptor class.
52 *
53 * @return The Cryptor.
54 */
55 public static synchronized Cryptor getCryptor() {
56 if (instance != null) {
57 return instance;
58 }
59
60 final String cryptorClass = System.getProperty(CRYPTOR_CLASS);
61 if (cryptorClass != null) {
62 try {
63 final Class<?> clazz = Class.forName(cryptorClass);
64 instance = (Cryptor) clazz.newInstance();
65 return instance;
66 } catch (final Exception ex) {
67 throw new RuntimeException("Unable to create Cryptor " + cryptorClass, ex);
68 }
69 }
70 instance = new DefaultCryptor();
71 return instance;
72 }
73 }