/* * Copyright 2004 The Apache Software Foundation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 3.0 */ using System; namespace Lucene.Net.QueryParsers { /// This interface describes a character stream that maintains line and /// column number positions of the characters. It also has the capability /// to backup the stream to some extent. An implementation of this /// interface is used in the TokenManager implementation generated by /// JavaCCParser. /// /// All the methods except backup can be implemented in any fashion. backup /// needs to be implemented correctly for the correct operation of the lexer. /// Rest of the methods are all used to get information like line number, /// column number and the String that constitutes a token and are not used /// by the lexer. Hence their implementation won't affect the generated lexer's /// operation. /// public interface CharStream { /// Returns the next character from the selected input. The method /// of selecting the input is the responsibility of the class /// implementing this interface. Can throw any java.io.IOException. /// char ReadChar(); /// Returns the column position of the character last read. /// /// /// /// int GetColumn(); /// Returns the line number of the character last read. /// /// /// /// int GetLine(); /// Returns the column number of the last character for current token (being /// matched after the last call to BeginTOken). /// int GetEndColumn(); /// Returns the line number of the last character for current token (being /// matched after the last call to BeginTOken). /// int GetEndLine(); /// Returns the column number of the first character for current token (being /// matched after the last call to BeginTOken). /// int GetBeginColumn(); /// Returns the line number of the first character for current token (being /// matched after the last call to BeginTOken). /// int GetBeginLine(); /// Backs up the input stream by amount steps. Lexer calls this method if it /// had already read some characters, but could not use them to match a /// (longer) token. So, they will be used again as the prefix of the next /// token and it is the implemetation's responsibility to do this right. /// void Backup(int amount); /// Returns the next character that marks the beginning of the next token. /// All characters must remain in the buffer between two successive calls /// to this method to implement backup correctly. /// char BeginToken(); /// Returns a string made up of characters from the marked token beginning /// to the current buffer position. Implementations have the choice of returning /// anything that they want to. For example, for efficiency, one might decide /// to just return null, which is a valid implementation. /// System.String GetImage(); /// Returns an array of characters that make up the suffix of length 'len' for /// the currently matched token. This is used to build up the matched string /// for use in actions in the case of MORE. A simple and inefficient /// implementation of this is as follows : /// /// { /// String t = GetImage(); /// return t.substring(t.length() - len, t.length()).toCharArray(); /// } /// char[] GetSuffix(int len); /// The lexer calls this function to indicate that it is done with the stream /// and hence implementations can free any resources held by this class. /// Again, the body of this function can be just empty and it will not /// affect the lexer's operation. /// void Done(); } }