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 javax.faces.validator;
20
21 import java.util.logging.Level;
22 import java.util.logging.Logger;
23
24 import javax.el.ELContext;
25
26 /**
27 * <p>
28 * Package-private utility class for determining which specifications are available
29 * in the current process. See JIRA issue: http://issues.apache.org/jira/browse/MYFACES-2386
30 * </p>
31 *
32 * @author Jan-Kees van Andel
33 * @author Jakob Korherr (latest modification by $Author: lu4242 $)
34 * @version $Revision: 1352028 $ $Date: 2012-06-20 04:55:03 -0500 (Wed, 20 Jun 2012) $
35 * @since 2.0
36 */
37 final class _ExternalSpecifications
38 {
39
40 //private static final Log log = LogFactory.getLog(BeanValidator.class);
41 private static final Logger log = Logger.getLogger(_ExternalSpecifications.class.getName());
42
43 private static volatile Boolean beanValidationAvailable;
44 private static volatile Boolean unifiedELAvailable;
45
46 /**
47 * This method determines if Bean Validation is present.
48 *
49 * Eager initialization is used for performance. This means Bean Validation binaries
50 * should not be added at runtime after this variable has been set.
51 * @return true if Bean Validation is available, false otherwise.
52 */
53 public static boolean isBeanValidationAvailable()
54 {
55 if (beanValidationAvailable == null)
56 {
57 try
58 {
59 try
60 {
61 beanValidationAvailable = (Class.forName("javax.validation.Validation") != null);
62 }
63 catch(ClassNotFoundException e)
64 {
65 beanValidationAvailable = Boolean.FALSE;
66 }
67
68 if (beanValidationAvailable)
69 {
70 try
71 {
72 // Trial-error approach to check for Bean Validation impl existence.
73 // If any Exception occurs here, we assume that Bean Validation is not available.
74 // The cause may be anything, i.e. NoClassDef, config error...
75 _ValidationUtils.tryBuildDefaultValidatorFactory();
76 }
77 catch (Throwable t)
78 {
79 log.log(Level.FINE, "Error initializing Bean Validation (could be normal)", t);
80 beanValidationAvailable = false;
81 }
82 }
83 }
84 catch (Throwable t)
85 {
86 log.log(Level.FINE, "Error loading class (could be normal)", t);
87 beanValidationAvailable = false;
88 }
89
90 //log.info("MyFaces Bean Validation support " + (beanValidationAvailable ? "enabled" : "disabled"));
91 }
92 return beanValidationAvailable;
93 }
94
95 /**
96 * This method determines if Unified EL is present.
97 *
98 * Eager initialization is used for performance. This means Unified EL binaries
99 * should not be added at runtime after this variable has been set.
100 * @return true if UEL is available, false otherwise.
101 */
102 public static boolean isUnifiedELAvailable()
103 {
104 if (unifiedELAvailable == null)
105 {
106 try
107 {
108 // Check if the UEL classes are available.
109 // If the JSP EL classes are loaded first, UEL will not work
110 // properly, hence it will be disabled.
111 unifiedELAvailable = (
112 Class.forName("javax.el.ValueReference") != null
113 && Class.forName("javax.el.ValueExpression")
114 .getMethod("getValueReference", ELContext.class) != null
115 );
116 }
117 catch (Throwable t)
118 {
119 log.log(Level.FINE, "Error loading class (could be normal)", t);
120 unifiedELAvailable = false;
121 }
122
123 //log.info("MyFaces Unified EL support " + (unifiedELAvailable ? "enabled" : "disabled"));
124 }
125 return unifiedELAvailable;
126 }
127
128 /**
129 * this class should not be instantiated.
130 */
131 private _ExternalSpecifications()
132 {
133 }
134
135 }