001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.vfs2.util; 018 019/** 020 * Factory to create an instance of a Cryptor. 021 * 022 * @since 2.0 023 */ 024public final class CryptorFactory { 025 /** 026 * The System property name to identify the Cryptor class to be used. 027 */ 028 public static final String CRYPTOR_CLASS = "org.apache.commons.vfs2.cryptor"; 029 030 private static Cryptor instance; 031 032 /** 033 * Prevent instantiation of the class. 034 */ 035 private CryptorFactory() { 036 037 } 038 039 /** 040 * Allows the Cryptor class to be set programmatically. 041 * 042 * @param cryptor The Cryptor. 043 */ 044 public static synchronized void setCryptor(final Cryptor cryptor) { 045 instance = cryptor; 046 } 047 048 /** 049 * Return the Cryptor. If one has not been previously set, create it. The Cryptor class can be set by setting the 050 * "org.apache.commons.vfs2.cryptor" System property to the name of the Cryptor class. 051 * 052 * @return The Cryptor. 053 */ 054 public static synchronized Cryptor getCryptor() { 055 if (instance != null) { 056 return instance; 057 } 058 059 final String cryptorClass = System.getProperty(CRYPTOR_CLASS); 060 if (cryptorClass != null) { 061 try { 062 final Class<?> clazz = Class.forName(cryptorClass); 063 instance = (Cryptor) clazz.newInstance(); 064 return instance; 065 } catch (final Exception ex) { 066 throw new RuntimeException("Unable to create Cryptor " + cryptorClass, ex); 067 } 068 } 069 instance = new DefaultCryptor(); 070 return instance; 071 } 072}