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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.util.Args;
36  import org.apache.http.util.CharArrayBuffer;
37  
38  /**
39   * This class represents a raw HTTP header whose content is parsed 'on demand'
40   * only when the header value needs to be consumed.
41   *
42   * @since 4.0
43   */
44  public class BufferedHeader implements FormattedHeader, Cloneable, Serializable {
45  
46      private static final long serialVersionUID = -2768352615787625448L;
47  
48      /**
49       * Header name.
50       */
51      private final String name;
52  
53      /**
54       * The buffer containing the entire header line.
55       */
56      private final CharArrayBuffer buffer;
57  
58      /**
59       * The beginning of the header value in the buffer
60       */
61      private final int valuePos;
62  
63  
64      /**
65       * Creates a new header from a buffer.
66       * The name of the header will be parsed immediately,
67       * the value only if it is accessed.
68       *
69       * @param buffer    the buffer containing the header to represent
70       *
71       * @throws ParseException   in case of a parse error
72       */
73      public BufferedHeader(final CharArrayBuffer buffer)
74          throws ParseException {
75  
76          super();
77          Args.notNull(buffer, "Char array buffer");
78          final int colon = buffer.indexOf(':');
79          if (colon == -1) {
80              throw new ParseException
81                  ("Invalid header: " + buffer.toString());
82          }
83          final String s = buffer.substringTrimmed(0, colon);
84          if (s.length() == 0) {
85              throw new ParseException
86                  ("Invalid header: " + buffer.toString());
87          }
88          this.buffer = buffer;
89          this.name = s;
90          this.valuePos = colon + 1;
91      }
92  
93  
94      @Override
95      public String getName() {
96          return this.name;
97      }
98  
99      @Override
100     public String getValue() {
101         return this.buffer.substringTrimmed(this.valuePos, this.buffer.length());
102     }
103 
104     @Override
105     public HeaderElement[] getElements() throws ParseException {
106         final ParserCursor cursor = new ParserCursor(0, this.buffer.length());
107         cursor.updatePos(this.valuePos);
108         return BasicHeaderValueParser.INSTANCE.parseElements(this.buffer, cursor);
109     }
110 
111     @Override
112     public int getValuePos() {
113         return this.valuePos;
114     }
115 
116     @Override
117     public CharArrayBuffer getBuffer() {
118         return this.buffer;
119     }
120 
121     @Override
122     public String toString() {
123         return this.buffer.toString();
124     }
125 
126     @Override
127     public Object clone() throws CloneNotSupportedException {
128         // buffer is considered immutable
129         // no need to make a copy of it
130         return super.clone();
131     }
132 
133 }