1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.myfaces.commons.resourcehandler.webapp.config.impl;
20
21 import org.apache.commons.logging.Log;
22 import org.apache.commons.logging.LogFactory;
23
24 /**
25 * <p>
26 * Package-private utility class for determining which specifications are available
27 * in the current process.
28 * </p>
29 *
30 * @author Leonardo Uribe
31 */
32 final class _ExternalSpecifications
33 {
34
35 private static final Log log = LogFactory.getLog(_ExternalSpecifications.class);
36
37 private static volatile Boolean servlet30Available;
38
39 /**
40 * This method determines if servlet 3.0 is present.
41 *
42 * @return true if servlet 3.0 is available, false otherwise.
43 */
44 public static boolean isServlet30Available()
45 {
46 if (servlet30Available == null)
47 {
48 try
49 {
50 servlet30Available = (Class.forName("javax.servlet.ServletRegistration") != null);
51 }
52 catch(Throwable t)
53 {
54 if (log.isTraceEnabled())
55 {
56 log.trace("Cannot load servlet 3.0 class (could be normal)", t);
57 }
58 servlet30Available = Boolean.FALSE;
59 }
60
61 log.info("MyFaces commons ResourceHandler Servlet 3.0 container support " + (servlet30Available ? "enabled" : "disabled"));
62 }
63 return servlet30Available;
64 }
65
66 /**
67 * this class should not be instantiated.
68 */
69 private _ExternalSpecifications()
70 {
71 }
72
73 }