Copyright (c) 2000, 2018 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2000, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.core.compiler;

import org.eclipse.jdt.core.compiler.InvalidInputException;

 

Caveat: With the introduction of "restricted keywords" in Java 9
it is impossible to classify a token without the help of a parser.
For that reason, this interface is not suitable for scanning a modular compilation unit
("module-info.java").
It is the client's responsibility to pass only source from ordinary compilation units.
For lack of a file name the scanner cannot check this.

Definition of a Java scanner, as returned by the ToolFactory.
The scanner is responsible for tokenizing a given source, providing information about
the nature of the token read, its positions and source equivalent.

When the scanner has finished tokenizing, it answers an EOF token (
ITerminalSymbols#TokenNameEOF.

When encountering lexical errors, an InvalidInputException is thrown.

See Also:
ToolFactory
ITerminalSymbols
Since:
2.0
@noimplement
This interface is not intended to be implemented by clients./**
  * <p>
  * <strong>Caveat:</strong> With the introduction of "restricted keywords" in Java 9
  * it is impossible to classify a token without the help of a parser.
  * For that reason, this interface is not suitable for scanning a modular compilation unit
  * ("module-info.java").
  * It is the client's responsibility to pass only source from ordinary compilation units.
  * For lack of a file name the scanner cannot check this.
  * </p>
  * 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 \\u0061bc then it will answer abc.
Returns:
the current identifier source, after unicode escape sequences have
been translated into unicode characters/**
	 * 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 \\u0061bc then it will answer \\u0061bc.
Returns:
the current identifier source, before unicode escape sequences have
been translated into unicode characters
Since:
2.1/**
	 * 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.
Returns:
the starting position of the current token inside the original source/**
	 * 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.
Returns:
the ending position of the current token inside the original source/**
	 * 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).
Params:
lineNumber – the given line number
Returns:
the starting position of a given line number/**
	 * 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).
Params:
lineNumber – the given line number
Returns:
the ending position of a given line number/**
	 * 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).
Returns:
an array of the ending positions of the lines encountered so far/**
	 * 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.
Params:
charPosition – the given character position
Returns:
a 1-based line number using the lines which have been encountered so far/**
	 * 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 ITerminalSymbols.
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
Returns:
the next token/**
	 * 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).
Returns:
the original source being processed/**
	 * 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 (ITerminalSymbols.TokenNameEOF).
Params:
startPosition – the given start position
endPosition – the given end position/**
	 * 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 null, this clears the source.
Params:
source – the given source/**
	 * 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);
}