1 /*
2 * Copyright 2007-2012 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springbyexample.web.context;
18
19 import javax.servlet.ServletContext;
20
21 import org.slf4j.Logger;
22 import org.slf4j.LoggerFactory;
23 import org.springframework.beans.factory.ObjectFactory;
24 import org.springframework.beans.factory.config.Scope;
25 import org.springframework.util.StringUtils;
26 import org.springframework.web.context.ServletContextAware;
27
28 /**
29 * <code>ServletContext</code> scope implementation.
30 * Can be used to share a bean from one web application to another
31 * if the web container has cross context support.
32 *
33 * @author David Winterfeldt
34 */
35 public class ServletContextScope implements Scope, ServletContextAware {
36
37 final Logger logger = LoggerFactory.getLogger(ServletContextScope.class);
38
39 protected ServletContext servletContext = null;
40 protected String context = null;
41
42 /**
43 * Implementation of <code>ServletContextAware</code>.
44 */
45 public void setServletContext(ServletContext servletContext) {
46 this.servletContext = servletContext;
47 }
48
49 /**
50 * Gets context to use when getting and setting
51 * a <code>ServletContext</code> attribute (ex: '/simple-form').
52 * If no context is specified, current one will be used.
53 */
54 public String getContext() {
55 return context;
56 }
57
58 /**
59 * Sets context to use when getting and setting
60 * a <code>ServletContext</code> attribute (ex: '/simple-form').
61 * If no context is specified, current one will be used.
62 */
63 public void setContext(String context) {
64 this.context = context;
65 }
66
67 /**
68 * Gets bean from scope.
69 */
70 public Object get(String name, ObjectFactory factory) {
71 Object result = null;
72
73 ServletContext sc = getServletContext();
74
75 result = sc.getAttribute(name);
76
77 if (result == null) {
78 result = factory.getObject();
79
80 sc.setAttribute(name, result);
81 }
82
83 return result;
84 }
85
86 /**
87 * Removes bean from scope.
88 */
89 public Object remove(String name) {
90 Object result = null;
91
92 ServletContext sc = getServletContext();
93
94 result = sc.getAttribute(name);
95
96 sc.removeAttribute(name);
97
98 return result;
99 }
100
101 /**
102 * <p>Registers destruction callback.</p>
103 *
104 * <p><strong>Note</strong>: Currently not implemented.</p>
105 */
106 public void registerDestructionCallback(String name, Runnable callback) {
107 logger.warn("ServletContextScope does not support descruction callbacks");
108 }
109
110 /**
111 * Resolve the contextual object for the given key, if any.
112 * Which in this case will always be <code>null</code>.
113 */
114 public Object resolveContextualObject(String key) {
115 return null;
116 }
117
118 /**
119 * <p>Gets conversation id.</p>
120 *
121 * <p><strong>Note</strong>: Currently not implemented.</p>
122 */
123 public String getConversationId() {
124 return null;
125 }
126
127 /**
128 * Gets current or cross context <code>ServletContext</code>.
129 */
130 protected ServletContext getServletContext() {
131 ServletContext sc = null;
132
133 if (StringUtils.hasText(context)) {
134 sc = servletContext.getContext(context);
135
136 if (sc == null) {
137 throw new UnsupportedOperationException("Unable to get context for '" + context + "'. " +
138 "Server may not have cross context support or may be configured incorrectly.");
139 }
140 } else {
141 sc = servletContext;
142 }
143
144 return sc;
145 }
146
147 }