CharStream


1   /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 3.0 */
2   /** 
3    * JSP Parser for PMD.
4    * @author Pieter � Application Engineers NV/SA � http://www.ae.be
5    */
6   
7   package net.sourceforge.pmd.jsp.ast;
8   
9   /**
10   * This interface describes a character stream that maintains line and
11   * column number positions of the characters.  It also has the capability
12   * to backup the stream to some extent.  An implementation of this
13   * interface is used in the TokenManager implementation generated by
14   * JavaCCParser.
15   * <p/>
16   * All the methods except backup can be implemented in any fashion. backup
17   * needs to be implemented correctly for the correct operation of the lexer.
18   * Rest of the methods are all used to get information like line number,
19   * column number and the String that constitutes a token and are not used
20   * by the lexer. Hence their implementation won't affect the generated lexer's
21   * operation.
22   */
23  
24  public interface CharStream extends net.sourceforge.pmd.ast.CharStream {
25  
26      /**
27       * Returns the next character from the selected input.  The method
28       * of selecting the input is the responsibility of the class
29       * implementing this interface.  Can throw any java.io.IOException.
30       */
31      char readChar() throws java.io.IOException  ;
32  
33      /**
34       * Returns the column position of the character last read.
35       *
36       * @see #getEndColumn
37       * @deprecated
38       */
39      int getColumn();
40  
41      /**
42       * Returns the line number of the character last read.
43       *
44       * @see #getEndLine
45       * @deprecated
46       */
47      int getLine();
48  
49      /**
50       * Returns the column number of the last character for current token (being
51       * matched after the last call to BeginTOken).
52       */
53      int getEndColumn();
54  
55      /**
56       * Returns the line number of the last character for current token (being
57       * matched after the last call to BeginTOken).
58       */
59      int getEndLine();
60  
61      /**
62       * Returns the column number of the first character for current token (being
63       * matched after the last call to BeginTOken).
64       */
65      int getBeginColumn();
66  
67      /**
68       * Returns the line number of the first character for current token (being
69       * matched after the last call to BeginTOken).
70       */
71      int getBeginLine();
72  
73      /**
74       * Backs up the input stream by amount steps. Lexer calls this method if it
75       * had already read some characters, but could not use them to match a
76       * (longer) token. So, they will be used again as the prefix of the next
77       * token and it is the implemetation's responsibility to do this right.
78       */
79      void backup(int amount);
80  
81      /**
82       * Returns the next character that marks the beginning of the next token.
83       * All characters must remain in the buffer between two successive calls
84       * to this method to implement backup correctly.
85       */
86      char BeginToken() throws java.io.IOException  ;
87  
88      /**
89       * Returns a string made up of characters from the marked token beginning
90       * to the current buffer position. Implementations have the choice of returning
91       * anything that they want to. For example, for efficiency, one might decide
92       * to just return null, which is a valid implementation.
93       */
94      String   GetImage();
95  
96      /**
97       * Returns an array of characters that make up the suffix of length 'len' for
98       * the currently matched token. This is used to build up the matched string
99       * for use in actions in the case of MORE. A simple and inefficient
100      * implementation of this is as follows :
101      * <p/>
102      * {
103      * String t = GetImage();
104      * return t.substring(t.length() - len, t.length()).toCharArray();
105      * }
106      */
107     char[] GetSuffix(int len);
108 
109     /**
110      * 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      */
115     void Done();
116 
117 }
118
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags