001/* Generated By:JavaCC: Do not edit this line. CharStream.java Version 5.0 */ 002/* JavaCCOptions:STATIC=false,SUPPORT_CLASS_VISIBILITY_PUBLIC=true */ 003package org.w3c.flute.parser; 004 005/** 006 * This interface describes a character stream that maintains line and 007 * column number positions of the characters. It also has the capability 008 * to backup the stream to some extent. An implementation of this 009 * interface is used in the TokenManager implementation generated by 010 * JavaCCParser. 011 * 012 * All the methods except backup can be implemented in any fashion. backup 013 * needs to be implemented correctly for the correct operation of the lexer. 014 * Rest of the methods are all used to get information like line number, 015 * column number and the String that constitutes a token and are not used 016 * by the lexer. Hence their implementation won't affect the generated lexer's 017 * operation. 018 */ 019 020public 021interface CharStream { 022 023 /** 024 * Returns the next character from the selected input. The method 025 * of selecting the input is the responsibility of the class 026 * implementing this interface. Can throw any java.io.IOException. 027 */ 028 char readChar() throws java.io.IOException; 029 030 @Deprecated 031 /** 032 * Returns the column position of the character last read. 033 * @deprecated 034 * @see #getEndColumn 035 */ 036 int getColumn(); 037 038 @Deprecated 039 /** 040 * Returns the line number of the character last read. 041 * @deprecated 042 * @see #getEndLine 043 */ 044 int getLine(); 045 046 /** 047 * Returns the column number of the last character for current token (being 048 * matched after the last call to BeginTOken). 049 */ 050 int getEndColumn(); 051 052 /** 053 * Returns the line number of the last character for current token (being 054 * matched after the last call to BeginTOken). 055 */ 056 int getEndLine(); 057 058 /** 059 * Returns the column number of the first character for current token (being 060 * matched after the last call to BeginTOken). 061 */ 062 int getBeginColumn(); 063 064 /** 065 * Returns the line number of the first character for current token (being 066 * matched after the last call to BeginTOken). 067 */ 068 int getBeginLine(); 069 070 /** 071 * Backs up the input stream by amount steps. Lexer calls this method if it 072 * had already read some characters, but could not use them to match a 073 * (longer) token. So, they will be used again as the prefix of the next 074 * token and it is the implemetation's responsibility to do this right. 075 */ 076 void backup(int amount); 077 078 /** 079 * Returns the next character that marks the beginning of the next token. 080 * All characters must remain in the buffer between two successive calls 081 * to this method to implement backup correctly. 082 */ 083 char BeginToken() throws java.io.IOException; 084 085 /** 086 * Returns a string made up of characters from the marked token beginning 087 * to the current buffer position. Implementations have the choice of returning 088 * anything that they want to. For example, for efficiency, one might decide 089 * to just return null, which is a valid implementation. 090 */ 091 String GetImage(); 092 093 /** 094 * Returns an array of characters that make up the suffix of length 'len' for 095 * the currently matched token. This is used to build up the matched string 096 * for use in actions in the case of MORE. A simple and inefficient 097 * implementation of this is as follows : 098 * 099 * { 100 * String t = GetImage(); 101 * return t.substring(t.length() - len, t.length()).toCharArray(); 102 * } 103 */ 104 char[] GetSuffix(int len); 105 106 /** 107 * The lexer calls this function to indicate that it is done with the stream 108 * and hence implementations can free any resources held by this class. 109 * Again, the body of this function can be just empty and it will not 110 * affect the lexer's operation. 111 */ 112 void Done(); 113 114} 115/* JavaCC - OriginalChecksum=9e13eaf20bbd60d420d5d89177ab64a7 (do not edit this line) */