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1   /*
2    * $Id: ApplicationMap.java 439747 2006-09-03 09:22:46Z mrdon $
3    *
4    * Copyright 2006 The Apache Software Foundation.
5    *
6    * Licensed under the Apache License, Version 2.0 (the "License");
7    * you may not use this file except in compliance with the License.
8    * 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, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.struts2.dispatcher;
19  
20  import java.io.Serializable;
21  import java.util.AbstractMap;
22  import java.util.Enumeration;
23  import java.util.HashSet;
24  import java.util.Map;
25  import java.util.Set;
26  
27  import javax.servlet.ServletContext;
28  
29  
30  /***
31   * A simple implementation of the {@link java.util.Map} interface to handle a collection of attributes and
32   * init parameters in a {@link javax.servlet.ServletContext} object. The {@link #entrySet()} method
33   * enumerates over all servlet context attributes and init parameters and returns a collection of both.
34   * Note, this will occur lazily - only when the entry set is asked for.
35   *
36   */
37  public class ApplicationMap extends AbstractMap implements Serializable {
38  
39  	private static final long serialVersionUID = 9136809763083228202L;
40  	
41  	private ServletContext context;
42      private Set<Object> entries;
43  
44  
45      /***
46       * Creates a new map object given the servlet context.
47       *
48       * @param ctx the servlet context
49       */
50      public ApplicationMap(ServletContext ctx) {
51          this.context = ctx;
52      }
53  
54  
55      /***
56       * Removes all entries from the Map and removes all attributes from the servlet context.
57       */
58      public void clear() {
59          entries = null;
60  
61          Enumeration e = context.getAttributeNames();
62  
63          while (e.hasMoreElements()) {
64              context.removeAttribute(e.nextElement().toString());
65          }
66      }
67  
68      /***
69       * Creates a Set of all servlet context attributes as well as context init parameters.
70       *
71       * @return a Set of all servlet context attributes as well as context init parameters.
72       */
73      public Set entrySet() {
74          if (entries == null) {
75              entries = new HashSet<Object>();
76  
77              // Add servlet context attributes
78              Enumeration enumeration = context.getAttributeNames();
79  
80              while (enumeration.hasMoreElements()) {
81                  final String key = enumeration.nextElement().toString();
82                  final Object value = context.getAttribute(key);
83                  entries.add(new Map.Entry() {
84                      public boolean equals(Object obj) {
85                          Map.Entry entry = (Map.Entry) obj;
86  
87                          return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
88                      }
89  
90                      public int hashCode() {
91                          return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
92                      }
93  
94                      public Object getKey() {
95                          return key;
96                      }
97  
98                      public Object getValue() {
99                          return value;
100                     }
101 
102                     public Object setValue(Object obj) {
103                         context.setAttribute(key.toString(), obj);
104 
105                         return value;
106                     }
107                 });
108             }
109 
110             // Add servlet context init params
111             enumeration = context.getInitParameterNames();
112 
113             while (enumeration.hasMoreElements()) {
114                 final String key = enumeration.nextElement().toString();
115                 final Object value = context.getInitParameter(key);
116                 entries.add(new Map.Entry() {
117                     public boolean equals(Object obj) {
118                         Map.Entry entry = (Map.Entry) obj;
119 
120                         return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
121                     }
122 
123                     public int hashCode() {
124                         return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
125                     }
126 
127                     public Object getKey() {
128                         return key;
129                     }
130 
131                     public Object getValue() {
132                         return value;
133                     }
134 
135                     public Object setValue(Object obj) {
136                         context.setAttribute(key.toString(), obj);
137 
138                         return value;
139                     }
140                 });
141             }
142         }
143 
144         return entries;
145     }
146 
147     /***
148      * Returns the servlet context attribute or init parameter based on the given key. If the
149      * entry is not found, <tt>null</tt> is returned.
150      *
151      * @param key the entry key.
152      * @return the servlet context attribute or init parameter or <tt>null</tt> if the entry is not found.
153      */
154     public Object get(Object key) {
155         // Try context attributes first, then init params
156         // This gives the proper shadowing effects
157         String keyString = key.toString();
158         Object value = context.getAttribute(keyString);
159 
160         return (value == null) ? context.getInitParameter(keyString) : value;
161     }
162 
163     /***
164      * Sets a servlet context attribute given a attribute name and value.
165      *
166      * @param key   the name of the attribute.
167      * @param value the value to set.
168      * @return the attribute that was just set.
169      */
170     public Object put(Object key, Object value) {
171         entries = null;
172         context.setAttribute(key.toString(), value);
173 
174         return get(key);
175     }
176 
177     /***
178      * Removes the specified servlet context attribute.
179      *
180      * @param key the attribute to remove.
181      * @return the entry that was just removed.
182      */
183     public Object remove(Object key) {
184         entries = null;
185 
186         Object value = get(key);
187         context.removeAttribute(key.toString());
188 
189         return value;
190     }
191 }