beagled/Lucene.Net/QueryParser/CharStream.cs

   1 /*
   2  * Copyright 2004 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 3.0 */
  17 using System;
  18 namespace Lucene.Net.QueryParsers
  19 {
  20
  21         /// <summary> This interface describes a character stream that maintains line and
  22         /// column number positions of the characters.  It also has the capability
  23         /// to backup the stream to some extent.  An implementation of this
  24         /// interface is used in the TokenManager implementation generated by
  25         /// JavaCCParser.
  26         ///
  27         /// All the methods except backup can be implemented in any fashion. backup
  28         /// needs to be implemented correctly for the correct operation of the lexer.
  29         /// Rest of the methods are all used to get information like line number,
  30         /// column number and the String that constitutes a token and are not used
  31         /// by the lexer. Hence their implementation won't affect the generated lexer's
  32         /// operation.
  33         /// </summary>
  34
  35         public interface CharStream
  36         {
  37
  38                 /// <summary> Returns the next character from the selected input.  The method
  39                 /// of selecting the input is the responsibility of the class
  40                 /// implementing this interface.  Can throw any java.io.IOException.
  41                 /// </summary>
  42                 char ReadChar();
  43
  44                 /// <summary> Returns the column position of the character last read.</summary>
  45                 /// <deprecated>
  46                 /// </deprecated>
  47                 /// <seealso cref="#getEndColumn">
  48                 /// </seealso>
  49                 int GetColumn();
  50
  51                 /// <summary> Returns the line number of the character last read.</summary>
  52                 /// <deprecated>
  53                 /// </deprecated>
  54                 /// <seealso cref="#getEndLine">
  55                 /// </seealso>
  56                 int GetLine();
  57
  58                 /// <summary> Returns the column number of the last character for current token (being
  59                 /// matched after the last call to BeginTOken).
  60                 /// </summary>
  61                 int GetEndColumn();
  62
  63                 /// <summary> Returns the line number of the last character for current token (being
  64                 /// matched after the last call to BeginTOken).
  65                 /// </summary>
  66                 int GetEndLine();
  67
  68                 /// <summary> Returns the column number of the first character for current token (being
  69                 /// matched after the last call to BeginTOken).
  70                 /// </summary>
  71                 int GetBeginColumn();
  72
  73                 /// <summary> Returns the line number of the first character for current token (being
  74                 /// matched after the last call to BeginTOken).
  75                 /// </summary>
  76                 int GetBeginLine();
  77
  78                 /// <summary> Backs up the input stream by amount steps. Lexer calls this method if it
  79                 /// had already read some characters, but could not use them to match a
  80                 /// (longer) token. So, they will be used again as the prefix of the next
  81                 /// token and it is the implemetation's responsibility to do this right.
  82                 /// </summary>
  83                 void  Backup(int amount);
  84
  85                 /// <summary> Returns the next character that marks the beginning of the next token.
  86                 /// All characters must remain in the buffer between two successive calls
  87                 /// to this method to implement backup correctly.
  88                 /// </summary>
  89                 char BeginToken();
  90
  91                 /// <summary> Returns a string made up of characters from the marked token beginning
  92                 /// to the current buffer position. Implementations have the choice of returning
  93                 /// anything that they want to. For example, for efficiency, one might decide
  94                 /// to just return null, which is a valid implementation.
  95                 /// </summary>
  96                 System.String GetImage();
  97
  98                 /// <summary> Returns an array of characters that make up the suffix of length 'len' for
  99                 /// the currently matched token. This is used to build up the matched string
 100                 /// for use in actions in the case of MORE. A simple and inefficient
 101                 /// implementation of this is as follows :
 102                 ///
 103                 /// {
 104                 /// String t = GetImage();
 105                 /// return t.substring(t.length() - len, t.length()).toCharArray();
 106                 /// }
 107                 /// </summary>
 108                 char[] GetSuffix(int len);
 109
 110                 /// <summary> The lexer calls this function to indicate that it is done with the stream
 111                 /// and hence implementations can free any resources held by this class.
 112                 /// Again, the body of this function can be just empty and it will not
 113                 /// affect the lexer's operation.
 114                 /// </summary>
 115                 void  Done();
 116         }
 117 }