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1   /*
2    * $Id: ApplicationMap.java 471756 2006-11-06 15:01:43Z husted $
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  package org.apache.struts2.dispatcher;
22  
23  import java.io.Serializable;
24  import java.util.AbstractMap;
25  import java.util.Enumeration;
26  import java.util.HashSet;
27  import java.util.Map;
28  import java.util.Set;
29  
30  import javax.servlet.ServletContext;
31  
32  
33  /***
34   * A simple implementation of the {@link java.util.Map} interface to handle a collection of attributes and
35   * init parameters in a {@link javax.servlet.ServletContext} object. The {@link #entrySet()} method
36   * enumerates over all servlet context attributes and init parameters and returns a collection of both.
37   * Note, this will occur lazily - only when the entry set is asked for.
38   *
39   */
40  public class ApplicationMap extends AbstractMap implements Serializable {
41  
42      private static final long serialVersionUID = 9136809763083228202L;
43  
44      private ServletContext context;
45      private Set<Object> entries;
46  
47  
48      /***
49       * Creates a new map object given the servlet context.
50       *
51       * @param ctx the servlet context
52       */
53      public ApplicationMap(ServletContext ctx) {
54          this.context = ctx;
55      }
56  
57  
58      /***
59       * Removes all entries from the Map and removes all attributes from the servlet context.
60       */
61      public void clear() {
62          entries = null;
63  
64          Enumeration e = context.getAttributeNames();
65  
66          while (e.hasMoreElements()) {
67              context.removeAttribute(e.nextElement().toString());
68          }
69      }
70  
71      /***
72       * Creates a Set of all servlet context attributes as well as context init parameters.
73       *
74       * @return a Set of all servlet context attributes as well as context init parameters.
75       */
76      public Set entrySet() {
77          if (entries == null) {
78              entries = new HashSet<Object>();
79  
80              // Add servlet context attributes
81              Enumeration enumeration = context.getAttributeNames();
82  
83              while (enumeration.hasMoreElements()) {
84                  final String key = enumeration.nextElement().toString();
85                  final Object value = context.getAttribute(key);
86                  entries.add(new Map.Entry() {
87                      public boolean equals(Object obj) {
88                          Map.Entry entry = (Map.Entry) obj;
89  
90                          return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
91                      }
92  
93                      public int hashCode() {
94                          return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
95                      }
96  
97                      public Object getKey() {
98                          return key;
99                      }
100 
101                     public Object getValue() {
102                         return value;
103                     }
104 
105                     public Object setValue(Object obj) {
106                         context.setAttribute(key.toString(), obj);
107 
108                         return value;
109                     }
110                 });
111             }
112 
113             // Add servlet context init params
114             enumeration = context.getInitParameterNames();
115 
116             while (enumeration.hasMoreElements()) {
117                 final String key = enumeration.nextElement().toString();
118                 final Object value = context.getInitParameter(key);
119                 entries.add(new Map.Entry() {
120                     public boolean equals(Object obj) {
121                         Map.Entry entry = (Map.Entry) obj;
122 
123                         return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
124                     }
125 
126                     public int hashCode() {
127                         return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
128                     }
129 
130                     public Object getKey() {
131                         return key;
132                     }
133 
134                     public Object getValue() {
135                         return value;
136                     }
137 
138                     public Object setValue(Object obj) {
139                         context.setAttribute(key.toString(), obj);
140 
141                         return value;
142                     }
143                 });
144             }
145         }
146 
147         return entries;
148     }
149 
150     /***
151      * Returns the servlet context attribute or init parameter based on the given key. If the
152      * entry is not found, <tt>null</tt> is returned.
153      *
154      * @param key the entry key.
155      * @return the servlet context attribute or init parameter or <tt>null</tt> if the entry is not found.
156      */
157     public Object get(Object key) {
158         // Try context attributes first, then init params
159         // This gives the proper shadowing effects
160         String keyString = key.toString();
161         Object value = context.getAttribute(keyString);
162 
163         return (value == null) ? context.getInitParameter(keyString) : value;
164     }
165 
166     /***
167      * Sets a servlet context attribute given a attribute name and value.
168      *
169      * @param key   the name of the attribute.
170      * @param value the value to set.
171      * @return the attribute that was just set.
172      */
173     public Object put(Object key, Object value) {
174         entries = null;
175         context.setAttribute(key.toString(), value);
176 
177         return get(key);
178     }
179 
180     /***
181      * Removes the specified servlet context attribute.
182      *
183      * @param key the attribute to remove.
184      * @return the entry that was just removed.
185      */
186     public Object remove(Object key) {
187         entries = null;
188 
189         Object value = get(key);
190         context.removeAttribute(key.toString());
191 
192         return value;
193     }
194 }