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1   /*
2    * $Id: ApplicationMap.java 768855 2009-04-27 02:09:35Z wesw $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  package org.apache.struts2.dispatcher;
23  
24  import java.io.Serializable;
25  import java.util.AbstractMap;
26  import java.util.Enumeration;
27  import java.util.HashSet;
28  import java.util.Map;
29  import java.util.Set;
30  
31  import javax.servlet.ServletContext;
32  
33  
34  /***
35   * A simple implementation of the {@link java.util.Map} interface to handle a collection of attributes and
36   * init parameters in a {@link javax.servlet.ServletContext} object. The {@link #entrySet()} method
37   * enumerates over all servlet context attributes and init parameters and returns a collection of both.
38   * Note, this will occur lazily - only when the entry set is asked for.
39   *
40   */
41  public class ApplicationMap extends AbstractMap implements Serializable {
42  
43      private static final long serialVersionUID = 9136809763083228202L;
44  
45      private ServletContext context;
46      private Set<Object> entries;
47  
48  
49      /***
50       * Creates a new map object given the servlet context.
51       *
52       * @param ctx the servlet context
53       */
54      public ApplicationMap(ServletContext ctx) {
55          this.context = ctx;
56      }
57  
58  
59      /***
60       * Removes all entries from the Map and removes all attributes from the servlet context.
61       */
62      public void clear() {
63          entries = null;
64  
65          Enumeration e = context.getAttributeNames();
66  
67          while (e.hasMoreElements()) {
68              context.removeAttribute(e.nextElement().toString());
69          }
70      }
71  
72      /***
73       * Creates a Set of all servlet context attributes as well as context init parameters.
74       *
75       * @return a Set of all servlet context attributes as well as context init parameters.
76       */
77      public Set entrySet() {
78          if (entries == null) {
79              entries = new HashSet<Object>();
80  
81              // Add servlet context attributes
82              Enumeration enumeration = context.getAttributeNames();
83  
84              while (enumeration.hasMoreElements()) {
85                  final String key = enumeration.nextElement().toString();
86                  final Object value = context.getAttribute(key);
87                  entries.add(new Map.Entry() {
88                      public boolean equals(Object obj) {
89                          if (!(obj instanceof Map.Entry)) {
90                            return false;
91                          }
92                          Map.Entry entry = (Map.Entry) obj;
93  
94                          return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
95                      }
96  
97                      public int hashCode() {
98                          return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
99                      }
100 
101                     public Object getKey() {
102                         return key;
103                     }
104 
105                     public Object getValue() {
106                         return value;
107                     }
108 
109                     public Object setValue(Object obj) {
110                         context.setAttribute(key, obj);
111 
112                         return value;
113                     }
114                 });
115             }
116 
117             // Add servlet context init params
118             enumeration = context.getInitParameterNames();
119 
120             while (enumeration.hasMoreElements()) {
121                 final String key = enumeration.nextElement().toString();
122                 final Object value = context.getInitParameter(key);
123                 entries.add(new Map.Entry() {
124                     public boolean equals(Object obj) {
125                         if (!(obj instanceof Map.Entry)) {
126                           return false;
127                         }
128                         Map.Entry entry = (Map.Entry) obj;
129 
130                         return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
131                     }
132 
133                     public int hashCode() {
134                         return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
135                     }
136 
137                     public Object getKey() {
138                         return key;
139                     }
140 
141                     public Object getValue() {
142                         return value;
143                     }
144 
145                     public Object setValue(Object obj) {
146                         context.setAttribute(key, obj);
147 
148                         return value;
149                     }
150                 });
151             }
152         }
153 
154         return entries;
155     }
156 
157     /***
158      * Returns the servlet context attribute or init parameter based on the given key. If the
159      * entry is not found, <tt>null</tt> is returned.
160      *
161      * @param key the entry key.
162      * @return the servlet context attribute or init parameter or <tt>null</tt> if the entry is not found.
163      */
164     public Object get(Object key) {
165         // Try context attributes first, then init params
166         // This gives the proper shadowing effects
167         String keyString = key.toString();
168         Object value = context.getAttribute(keyString);
169 
170         return (value == null) ? context.getInitParameter(keyString) : value;
171     }
172 
173     /***
174      * Sets a servlet context attribute given a attribute name and value.
175      *
176      * @param key   the name of the attribute.
177      * @param value the value to set.
178      * @return the attribute that was just set.
179      */
180     public Object put(Object key, Object value) {
181         entries = null;
182         context.setAttribute(key.toString(), value);
183 
184         return get(key);
185     }
186 
187     /***
188      * Removes the specified servlet context attribute.
189      *
190      * @param key the attribute to remove.
191      * @return the entry that was just removed.
192      */
193     public Object remove(Object key) {
194         entries = null;
195 
196         Object value = get(key);
197         context.removeAttribute(key.toString());
198 
199         return value;
200     }
201 }