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1   /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 0.7pre6 */
2   
3   /**
4    * Redistribution and use of this software and associated documentation ("Software"), with or
5    * without modification, are permitted provided that the following conditions are met:
6    *
7    * 1. Redistributions of source code must retain copyright statements and notices. Redistributions
8    * must also contain a copy of this document.
9    *
10   * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
11   * conditions and the following disclaimer in the documentation and/or other materials provided with
12   * the distribution.
13   *
14   * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software
15   * without prior written permission of Intalio, Inc. For written permission, please contact
16   * info@exolab.org.
17   *
18   * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in
19   * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of
20   * Intalio, Inc.
21   *
22   * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/).
23   *
24   * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR
25   * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
26   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS
27   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
30   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
31   * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32   *
33   * Copyright 2000 (C) Intalio Inc. All Rights Reserved.
34   *
35   * $Id$
36   */
37  
38  package org.exolab.castor.xml.dtd.parser;
39  
40  /**
41   * This interface describes a character stream that maintains line and column number positions of
42   * the characters. It also has the capability to backup the stream to some extent. An implementation
43   * of this interface is used in the TokenManager implementation generated by JavaCCParser.
44   * <p>
45   * All the methods except backup can be implemented in any fashion. backup needs to be implemented
46   * correctly for the correct operation of the lexer. Rest of the methods are all used to get
47   * information like line number, column number and the String that constitutes a token and are not
48   * used by the lexer. Hence their implementation won't affect the generated lexer's operation.
49   *
50   * @author Generated automatically by <b>JavaCC</b>
51   * @version Version 0.7pre6
52   */
53  abstract public interface CharStream {
54  
55    /**
56     * Returns the next character from the selected input. The method of selecting the input is the
57     * responsibility of the class implementing this interface. Can throw any java.io.IOException.
58     */
59    abstract public char readChar() throws java.io.IOException;
60  
61    /**
62     * Returns the column position of the character last read.
63     * 
64     * @deprecated
65     * @see #getEndColumn
66     */
67    abstract public int getColumn();
68  
69    /**
70     * Returns the line number of the character last read.
71     * 
72     * @deprecated
73     * @see #getEndLine
74     */
75    abstract public int getLine();
76  
77    /**
78     * Returns the column number of the last character for current token (being matched after the last
79     * call to BeginTOken).
80     */
81    abstract public int getEndColumn();
82  
83    /**
84     * Returns the line number of the last character for current token (being matched after the last
85     * call to BeginTOken).
86     */
87    abstract public int getEndLine();
88  
89    /**
90     * Returns the column number of the first character for current token (being matched after the
91     * last call to BeginTOken).
92     */
93    abstract public int getBeginColumn();
94  
95    /**
96     * Returns the line number of the first character for current token (being matched after the last
97     * call to BeginTOken).
98     */
99    abstract public int getBeginLine();
100 
101   /**
102    * Backs up the input stream by amount steps. Lexer calls this method if it had already read some
103    * characters, but could not use them to match a (longer) token. So, they will be used again as
104    * the prefix of the next token and it is the implemetation's responsibility to do this right.
105    */
106   abstract public void backup(int amount);
107 
108   /**
109    * Returns the next character that marks the beginning of the next token. All characters must
110    * remain in the buffer between two successive calls to this method to implement backup correctly.
111    */
112   abstract public char BeginToken() throws java.io.IOException;
113 
114   /**
115    * Returns a string made up of characters from the marked token beginning to the current buffer
116    * position. Implementations have the choice of returning anything that they want to. For example,
117    * for efficiency, one might decide to just return null, which is a valid implementation.
118    */
119   abstract public String GetImage();
120 
121   /**
122    * Returns an array of characters that make up the suffix of length 'len' for the currently
123    * matched token. This is used to build up the matched string for use in actions in the case of
124    * MORE. A simple and inefficient implementation of this is as follows :
125    * 
126    * <pre>
127    * {
128    *   String t = GetImage();
129    *   return t.substring(t.length() - len, t.length()).toCharArray();
130    * }
131    * </pre>
132    */
133   abstract public char[] GetSuffix(int len);
134 
135   /**
136    * The lexer calls this function to indicate that it is done with the stream and hence
137    * implementations can free any resources held by this class. Again, the body of this function can
138    * be just empty and it will not affect the lexer's operation.
139    */
140   abstract public void Done();
141 
142 }