/*******************************************************************************
* Copyright (c) 2000, 2008 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.core.compiler;
import org.eclipse.jdt.core.compiler.InvalidInputException;
/**
* Definition of a Java scanner, as returned by the <code>ToolFactory</code>.
* The scanner is responsible for tokenizing a given source, providing information about
* the nature of the token read, its positions and source equivalent.
* <p>
* When the scanner has finished tokenizing, it answers an EOF token (<code>
* ITerminalSymbols#TokenNameEOF</code>.
* </p><p>
* When encountering lexical errors, an <code>InvalidInputException</code> is thrown.
* </p>
*
* @see org.eclipse.jdt.core.ToolFactory
* @see ITerminalSymbols
* @since 2.0
* @noimplement This interface is not intended to be implemented by clients.
*/
public interface IScanner {
/**
* Answers the current identifier source, after unicode escape sequences have
* been translated into unicode characters.
* For example, if original source was <code>\\u0061bc</code> then it will answer <code>abc</code>.
*
* @return the current identifier source, after unicode escape sequences have
* been translated into unicode characters
*/
char[] getCurrentTokenSource();
/**
* Answers the current identifier source, before unicode escape sequences have
* been translated into unicode characters.
* For example, if original source was <code>\\u0061bc</code> then it will answer <code>\\u0061bc</code>.
*
* @return the current identifier source, before unicode escape sequences have
* been translated into unicode characters
* @since 2.1
*/
char[] getRawTokenSource();
/**
* Answers the starting position of the current token inside the original source.
* This position is zero-based and inclusive. It corresponds to the position of the first character
* which is part of this token. If this character was a unicode escape sequence, it points at the first
* character of this sequence.
*
* @return the starting position of the current token inside the original source
*/
int getCurrentTokenStartPosition();
/**
* Answers the ending position of the current token inside the original source.
* This position is zero-based and inclusive. It corresponds to the position of the last character
* which is part of this token. If this character was a unicode escape sequence, it points at the last
* character of this sequence.
*
* @return the ending position of the current token inside the original source
*/
int getCurrentTokenEndPosition();
/**
* Answers the starting position of a given line number. This line has to have been encountered
* already in the tokenization process (in other words, it cannot be used to compute positions of lines beyond
* current token). Once the entire source has been processed, it can be used without any limit.
* Line starting positions are zero-based, and start immediately after the previous line separator (if any).
*
* @param lineNumber the given line number
* @return the starting position of a given line number
*/
int getLineStart(int lineNumber);
/**
* Answers the ending position of a given line number. This line has to have been encountered
* already in the tokenization process (in other words, it cannot be used to compute positions of lines beyond
* current token). Once the entire source has been processed, it can be used without any limit.
* Line ending positions are zero-based, and correspond to the last character of the line separator
* (in case multi-character line separators).
*
* @param lineNumber the given line number
* @return the ending position of a given line number
**/
int getLineEnd(int lineNumber);
/**
* Answers an array of the ending positions of the lines encountered so far. Line ending positions
* are zero-based, and correspond to the last character of the line separator (in case multi-character
* line separators).
*
* @return an array of the ending positions of the lines encountered so far
*/
int[] getLineEnds();
/**
* Answers a 1-based line number using the lines which have been encountered so far. If the position
* is located beyond the current scanned line, then the last line number will be answered.
*
* @param charPosition the given character position
* @return a 1-based line number using the lines which have been encountered so far
*/
int getLineNumber(int charPosition);
/**
* Read the next token in the source, and answers its ID as specified by <code>ITerminalSymbols</code>.
* Note that the actual token ID values are subject to change if new keywords were added to the language
* (for instance, 'assert' is a keyword in 1.4).
*
* @throws InvalidInputException in case a lexical error was detected while reading the current token
* @return the next token
*/
int getNextToken() throws InvalidInputException;
/**
* Answers the original source being processed (not a copy of it).
*
* @return the original source being processed
*/
char[] getSource();
/**
* Reposition the scanner on some portion of the original source. The given endPosition is the last valid position.
* Beyond this position, the scanner will answer EOF tokens (<code>ITerminalSymbols.TokenNameEOF</code>).
*
* @param startPosition the given start position
* @param endPosition the given end position
*/
void resetTo(int startPosition, int endPosition);
/**
* Set the scanner source to process. By default, the scanner will consider starting at the beginning of the
* source until it reaches its end.
* If the given source is <code>null</code>, this clears the source.
*
* @param source the given source
*/
void setSource(char[] source);
}