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    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 }