RequestMap


1   /*
2    * Copyright (c) 2002-2003 by OpenSymphony
3    * All rights reserved.
4    */
5   package com.opensymphony.webwork.dispatcher;
6   
7   import javax.servlet.http.HttpServletRequest  ;
8   import java.io.Serializable  ;
9   import java.util.AbstractMap  ;
10  import java.util.Enumeration  ;
11  import java.util.HashSet  ;
12  import java.util.Set  ;
13  
14  
15  /**
16   * A simple implementation of the {@link java.util.Map} interface to handle a collection of request attributes.
17   *
18   * @author Patrick Lightbody
19   * @author Bill Lynch (docs)
20   */
21  public class RequestMap extends AbstractMap   implements Serializable   {
22      //~ Instance fields ////////////////////////////////////////////////////////
23  
24      Set   entries;
25      private HttpServletRequest   request;
26  
27      //~ Constructors ///////////////////////////////////////////////////////////
28  
29      /**
30       * Saves the request to use as the backing for getting and setting values
31       *
32       * @param request the http servlet request.
33       */
34      public RequestMap(final HttpServletRequest   request) {
35          this.request = request;
36      }
37  
38      //~ Methods ////////////////////////////////////////////////////////////////
39  
40      /**
41       * Removes all attributes from the request as well as clears entries in this map.
42       */
43      public void clear() {
44          Enumeration   keys = request.getAttributeNames();
45  
46          while (keys.hasMoreElements()) {
47              String   key = (String  ) keys.nextElement();
48              request.removeAttribute(key);
49          }
50      }
51  
52      /**
53       * Returns a Set of attributes from the http request.
54       *
55       * @return a Set of attributes from the http request.
56       */
57      public Set   entrySet() {
58          if (entries == null) {
59              entries = new HashSet  ();
60  
61              Enumeration   enumeration = request.getAttributeNames();
62  
63              while (enumeration.hasMoreElements()) {
64                  final String   key = enumeration.nextElement().toString();
65                  final Object   value = request.getAttribute(key);
66                  entries.add(new Entry() {
67                      public boolean equals(Object   obj) {
68                          Entry entry = (Entry) obj;
69  
70                          return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
71                      }
72  
73                      public int hashCode() {
74                          return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
75                      }
76  
77                      public Object   getKey() {
78                          return key;
79                      }
80  
81                      public Object   getValue() {
82                          return value;
83                      }
84  
85                      public Object   setValue(Object   obj) {
86                          request.setAttribute(key.toString(), obj);
87  
88                          return value;
89                      }
90                  });
91              }
92          }
93  
94          return entries;
95      }
96  
97      /**
98       * Returns the request attribute associated with the given key or <tt>null</tt> if it doesn't exist.
99       *
100      * @param key the name of the request attribute.
101      * @return the request attribute or <tt>null</tt> if it doesn't exist.
102      */
103     public Object   get(Object   key) {
104         return request.getAttribute(key.toString());
105     }
106 
107     /**
108      * Saves an attribute in the request.
109      *
110      * @param key   the name of the request attribute.
111      * @param value the value to set.
112      * @return the object that was just set.
113      */
114     public Object   put(Object   key, Object   value) {
115         entries = null;
116         request.setAttribute(key.toString(), value);
117 
118         return get(key);
119     }
120 
121     /**
122      * Removes the specified request attribute.
123      *
124      * @param key the name of the attribute to remove.
125      * @return the value that was removed or <tt>null</tt> if the value was not found (and hence, not removed).
126      */
127     public Object   remove(Object   key) {
128         entries = null;
129 
130         Object   value = get(key);
131         request.removeAttribute(key.toString());
132 
133         return value;
134     }
135 }
136
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