org.neo4j.cypher.internal.parser.javacc.CharStream Maven / Gradle / Ivy
/* Generated by: ParserGeneratorCC: Do not edit this line. CharStream.java Version 1.1 */
/* ParserGeneratorCCOptions:SUPPORT_CLASS_VISIBILITY_PUBLIC=true */
/*
* Copyright (c) "Neo4j"
* Neo4j Sweden AB [https://neo4j.com]
*
* 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.
*/
package org.neo4j.cypher.internal.parser.javacc;
/**
* 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 {
/**
* Get the next character from the selected input. The method
* of selecting the input is the responsibility of the class
* implementing this interface.
* @return the next character from the selected input
* @throws java.io.IOException on IO error
*/
char readChar() throws java.io.IOException;
/**
* @return the column number of the first character for current token (being
* matched after the last call to beginToken).
*/
int getBeginColumn();
/**
* @return the line number of the first character for current token (being
* matched after the last call to BeginToken).
*/
int getBeginLine();
/**
* @return the column number of the last character for current token (being
* matched after the last call to BeginToken).
*/
int getEndColumn();
/**
* @return the line number of the last character for current token (being
* matched after the last call to BeginToken).
*/
int getEndLine();
/**
* 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.
* @param amount Number of chars to back up.
*/
void backup(int amount);
/**
* @return 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() throws java.io.IOException;
/**
* @return 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.
*/
String getImage();
/**
* @return 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();
// Getters and setters
/**
* @return Current tab size.
*/
int getTabSize();
/**
* Set the tab size to use.
* @param i spaces per tab
*/
void setTabSize(int i);
/**
* @return true if line number and column numbers should be tracked.
*/
boolean isTrackLineColumn();
/**
* Enable or disable line number and column number tracking.
* @param trackLineColumn true to track it, false to not do it.
*/
void setTrackLineColumn(boolean trackLineColumn);
}
/* ParserGeneratorCC - OriginalChecksum=a3722a896695cc8e579bef7583de89f4 (do not edit this line) */