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
20 package org.apache.myfaces.el.unified.resolver;
21
22 import javax.el.ELContext;
23 import javax.el.ELException;
24 import javax.el.PropertyNotFoundException;
25 import javax.faces.FacesException;
26 import javax.faces.context.ExternalContext;
27 import javax.faces.context.FacesContext;
28
29 import org.apache.myfaces.config.element.ManagedBean;
30
31 import com.google.inject.Injector;
32
33 /**
34 * <p>
35 * Register this ELResolver in faces-config.xml.
36 * </p>
37 *
38 * <application> <el-resolver>org.apache.myfaces.el.unified.resolver.GuiceResolver</el-resolver> </application>
39 *
40 * <p>
41 * Implement and configure a ServletContextListener in web.xml .
42 * </p>
43 *
44 * <listener> <listener-class>com.your_company.GuiceServletContextListener</listener-class> </listener>
45 *
46 * <p>
47 * Configure Guice in your ServletContextListener implementation, and place the Injector in application scope.
48 * </p>
49 *
50 * public class GuiceServletContextListener implements ServletContextListener {
51 *
52 * public void contextInitialized(ServletContextEvent event) { ServletContext ctx = event.getServletContext(); //when on
53 * Java6, use ServiceLoader.load(com.google.inject.Module.class); Injector injector = Guice.createInjector(new
54 * YourModule()); ctx.setAttribute(GuiceResolver.KEY, injector); }
55 *
56 * public void contextDestroyed(ServletContextEvent event) { ServletContext ctx = event.getServletContext();
57 * ctx.removeAttribute(GuiceResolver.KEY); }
58 *
59 *}
60 *
61 * @author Dennis Byrne
62 */
63
64 public class GuiceResolver extends ManagedBeanResolver
65 {
66
67 public static final String KEY = "oam." + Injector.class.getName();
68
69 @Override
70 public Object getValue(ELContext ctx, Object base, Object property) throws NullPointerException,
71 PropertyNotFoundException, ELException
72 {
73
74 if (base != null || !(property instanceof String))
75 {
76 return null;
77 }
78
79 FacesContext fctx = (FacesContext)ctx.getContext(FacesContext.class);
80
81 if (fctx == null)
82 {
83 return null;
84 }
85
86 ExternalContext ectx = fctx.getExternalContext();
87
88 if (ectx == null || ectx.getRequestMap().containsKey(property) || ectx.getSessionMap().containsKey(property)
89 || ectx.getApplicationMap().containsKey(property))
90 {
91 return null;
92 }
93
94 ManagedBean managedBean = runtimeConfig(ctx).getManagedBean((String)property);
95
96 return managedBean == null ? null : getValue(ctx, ectx, managedBean.getManagedBeanClass());
97 }
98
99 private Object getValue(ELContext ctx, ExternalContext ectx, Class<?> managedBeanClass)
100 {
101
102 Injector injector = (Injector)ectx.getApplicationMap().get(KEY);
103
104 if (injector == null)
105 {
106 throw new FacesException("Could not find an instance of " + Injector.class.getName()
107 + " in application scope using key '" + KEY + "'");
108 }
109
110 Object value = injector.getInstance(managedBeanClass);
111 ctx.setPropertyResolved(true);
112 return value;
113 }
114
115 }