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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.protocol;
29  
30  import java.util.HashMap;
31  import java.util.Map;
32  
33  import org.apache.http.annotation.NotThreadSafe;
34  
35  /**
36   * Default implementation of {@link HttpContext}.
37   * <p>
38   * Please note methods of this class are not synchronized and therefore may
39   * be threading unsafe.
40   *
41   * @since 4.0
42   */
43  @NotThreadSafe
44  public class BasicHttpContext implements HttpContext {
45  
46      private final HttpContext parentContext;
47      private Map<String, Object> map = null;
48  
49      public BasicHttpContext() {
50          this(null);
51      }
52  
53      public BasicHttpContext(final HttpContext parentContext) {
54          super();
55          this.parentContext = parentContext;
56      }
57  
58      public Object getAttribute(final String id) {
59          if (id == null) {
60              throw new IllegalArgumentException("Id may not be null");
61          }
62          Object obj = null;
63          if (this.map != null) {
64              obj = this.map.get(id);
65          }
66          if (obj == null && this.parentContext != null) {
67              obj = this.parentContext.getAttribute(id);
68          }
69          return obj;
70      }
71  
72      public void setAttribute(final String id, final Object obj) {
73          if (id == null) {
74              throw new IllegalArgumentException("Id may not be null");
75          }
76          if (this.map == null) {
77              this.map = new HashMap<String, Object>();
78          }
79          this.map.put(id, obj);
80      }
81  
82      public Object removeAttribute(final String id) {
83          if (id == null) {
84              throw new IllegalArgumentException("Id may not be null");
85          }
86          if (this.map != null) {
87              return this.map.remove(id);
88          } else {
89              return null;
90          }
91      }
92  
93      /**
94       * @since 4.2
95       */
96      public void clear() {
97          if (this.map != null) {
98              this.map.clear();
99          }
100     }
101 
102     @Override
103     public String toString() {
104         if (this.map != null) {
105             return this.map.toString();
106         } else {
107             return "{}";
108         }
109     }
110 }