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.el.unified;
20
21 import java.util.Comparator;
22 import java.util.List;
23
24 import javax.el.ELResolver;
25 import javax.faces.context.ExternalContext;
26 import javax.faces.context.FacesContext;
27
28 import org.apache.myfaces.config.RuntimeConfig;
29
30 /**
31 * Comparator for ELResolvers that shifts the Resolvers from
32 * the faces-config to the front.
33 *
34 * @author Jakob Korherr (latest modification by $Author$)
35 * @version $Revision$ $Date$
36 *
37 * @since 1.2.10, 2.0.2
38 */
39 public class CustomFirstELResolverComparator implements Comparator<ELResolver>
40 {
41
42 private List<ELResolver> _facesConfigResolvers;
43
44 public int compare(ELResolver r1, ELResolver r2)
45 {
46 List<ELResolver> facesConfigResolvers = _getFacesConfigElResolvers();
47
48 if (facesConfigResolvers == null)
49 {
50 // no el-resolvers in faces-config
51 return 0; // keep order
52 }
53
54 boolean r1FromFacesConfig = facesConfigResolvers.contains(r1);
55 boolean r2FromFacesConfig = facesConfigResolvers.contains(r2);
56
57 if (r1FromFacesConfig)
58 {
59 if (r2FromFacesConfig)
60 {
61 // both are from faces-config
62 return 0; // keep order
63 }
64 else
65 {
66 // only r1 is from faces-config
67 return -1;
68 }
69 }
70 else
71 {
72 if (r2FromFacesConfig)
73 {
74 // only r2 is from faces-config
75 return 1;
76 }
77 else
78 {
79 // neither r1 nor r2 are from faces-config
80 return 0; // keep order
81 }
82 }
83 }
84
85 /**
86 * Returns a List of all ELResolvers from the faces-config.
87 * @return
88 */
89 private List<ELResolver> _getFacesConfigElResolvers()
90 {
91 if (_facesConfigResolvers == null)
92 {
93 ExternalContext externalContext
94 = FacesContext.getCurrentInstance().getExternalContext();
95 RuntimeConfig runtimeConfig
96 = RuntimeConfig.getCurrentInstance(externalContext);
97 _facesConfigResolvers
98 = runtimeConfig.getFacesConfigElResolvers();
99 }
100
101 return _facesConfigResolvers;
102 }
103
104 }