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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 org.apache.http.ProtocolVersion;
31  import org.apache.http.ParseException;
32  import org.apache.http.RequestLine;
33  import org.apache.http.StatusLine;
34  import org.apache.http.Header;
35  import org.apache.http.util.CharArrayBuffer;
36  
37  /**
38   * Interface for parsing lines in the HEAD section of an HTTP message.
39   * There are individual methods for parsing a request line, a
40   * status line, or a header line.
41   * The lines to parse are passed in memory, the parser does not depend
42   * on any specific IO mechanism.
43   * Instances of this interface are expected to be stateless and thread-safe.
44   *
45   * @since 4.0
46   */
47  public interface LineParser {
48  
49      /**
50       * Parses the textual representation of a protocol version.
51       * This is needed for parsing request lines (last element)
52       * as well as status lines (first element).
53       *
54       * @param buffer    a buffer holding the protocol version to parse
55       * @param cursor    the parser cursor containing the current position and
56       *                  the bounds within the buffer for the parsing operation
57       *
58       * @return  the parsed protocol version
59       *
60       * @throws ParseException        in case of a parse error
61       */
62      ProtocolVersion parseProtocolVersion(
63              CharArrayBuffer buffer,
64              ParserCursor cursor) throws ParseException;
65  
66      /**
67       * Checks whether there likely is a protocol version in a line.
68       * This method implements a <i>heuristic</i> to check for a
69       * likely protocol version specification. It does <i>not</i>
70       * guarantee that {@link #parseProtocolVersion} would not
71       * detect a parse error.
72       * This can be used to detect garbage lines before a request
73       * or status line.
74       *
75       * @param buffer    a buffer holding the line to inspect
76       * @param cursor    the cursor at which to check for a protocol version, or
77       *                  negative for "end of line". Whether the check tolerates
78       *                  whitespace before or after the protocol version is
79       *                  implementation dependent.
80       *
81       * @return  <code>true</code> if there is a protocol version at the
82       *          argument index (possibly ignoring whitespace),
83       *          <code>false</code> otherwise
84       */
85      boolean hasProtocolVersion(
86              CharArrayBuffer buffer,
87              ParserCursor cursor);
88  
89      /**
90       * Parses a request line.
91       *
92       * @param buffer    a buffer holding the line to parse
93       * @param cursor    the parser cursor containing the current position and
94       *                  the bounds within the buffer for the parsing operation
95       *
96       * @return  the parsed request line
97       *
98       * @throws ParseException        in case of a parse error
99       */
100     RequestLine parseRequestLine(
101             CharArrayBuffer buffer,
102             ParserCursor cursor) throws ParseException;
103 
104     /**
105      * Parses a status line.
106      *
107      * @param buffer    a buffer holding the line to parse
108      * @param cursor    the parser cursor containing the current position and
109      *                  the bounds within the buffer for the parsing operation
110      *
111      * @return  the parsed status line
112      *
113      * @throws ParseException        in case of a parse error
114      */
115     StatusLine parseStatusLine(
116             CharArrayBuffer buffer,
117             ParserCursor cursor) throws ParseException;
118 
119     /**
120      * Creates a header from a line.
121      * The full header line is expected here. Header continuation lines
122      * must be joined by the caller before invoking this method.
123      *
124      * @param buffer    a buffer holding the full header line.
125      *                  This buffer MUST NOT be re-used afterwards, since
126      *                  the returned object may reference the contents later.
127      *
128      * @return  the header in the argument buffer.
129      *          The returned object MAY be a wrapper for the argument buffer.
130      *          The argument buffer MUST NOT be re-used or changed afterwards.
131      *
132      * @throws ParseException        in case of a parse error
133      */
134     Header parseHeader(CharArrayBuffer buffer)
135         throws ParseException;
136 
137 }