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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.message;
29  
30  import java.io.Serializable;
31  
32  import org.apache.http.FormattedHeader;
33  import org.apache.http.HeaderElement;
34  import org.apache.http.ParseException;
35  import org.apache.http.annotation.NotThreadSafe;
36  import org.apache.http.util.Args;
37  import org.apache.http.util.CharArrayBuffer;
38  
39  /**
40   * This class represents a raw HTTP header whose content is parsed 'on demand'
41   * only when the header value needs to be consumed.
42   *
43   * @since 4.0
44   */
45  @NotThreadSafe
46  public class BufferedHeader implements FormattedHeader, Cloneable, Serializable {
47  
48      private static final long serialVersionUID = -2768352615787625448L;
49  
50      /**
51       * Header name.
52       */
53      private final String name;
54  
55      /**
56       * The buffer containing the entire header line.
57       */
58      private final CharArrayBuffer buffer;
59  
60      /**
61       * The beginning of the header value in the buffer
62       */
63      private final int valuePos;
64  
65  
66      /**
67       * Creates a new header from a buffer.
68       * The name of the header will be parsed immediately,
69       * the value only if it is accessed.
70       *
71       * @param buffer    the buffer containing the header to represent
72       *
73       * @throws ParseException   in case of a parse error
74       */
75      public BufferedHeader(final CharArrayBuffer buffer)
76          throws ParseException {
77  
78          super();
79          Args.notNull(buffer, "Char array buffer");
80          final int colon = buffer.indexOf(':');
81          if (colon == -1) {
82              throw new ParseException
83                  ("Invalid header: " + buffer.toString());
84          }
85          final String s = buffer.substringTrimmed(0, colon);
86          if (s.length() == 0) {
87              throw new ParseException
88                  ("Invalid header: " + buffer.toString());
89          }
90          this.buffer = buffer;
91          this.name = s;
92          this.valuePos = colon + 1;
93      }
94  
95  
96      public String getName() {
97          return this.name;
98      }
99  
100     public String getValue() {
101         return this.buffer.substringTrimmed(this.valuePos, this.buffer.length());
102     }
103 
104     public HeaderElement[] getElements() throws ParseException {
105         final ParserCursor cursor = new ParserCursor(0, this.buffer.length());
106         cursor.updatePos(this.valuePos);
107         return BasicHeaderValueParser.INSTANCE.parseElements(this.buffer, cursor);
108     }
109 
110     public int getValuePos() {
111         return this.valuePos;
112     }
113 
114     public CharArrayBuffer getBuffer() {
115         return this.buffer;
116     }
117 
118     @Override
119     public String toString() {
120         return this.buffer.toString();
121     }
122 
123     @Override
124     public Object clone() throws CloneNotSupportedException {
125         // buffer is considered immutable
126         // no need to make a copy of it
127         return super.clone();
128     }
129 
130 }