Package org.flag4j.complex_numbers

Class CNumberLexer

java.lang.Object

org.flag4j.complex_numbers.CNumberLexer

class CNumberLexer
extends Object

A lexer for producing the tokens of a complex number represented as a string.

Field Summary

Fields

Modifier and Type	Field	Description
protected String	content	Content of the lexer.
private static final String	ERR_MSG	Error message for unexpected symbol.

Constructor Summary

Constructors

Constructor	Description
CNumberLexer(String content)

Method Summary

Modifier and Type	Method	Description
protected boolean	digit(int code)
protected static void	error(String message)	Stops execution with an error message
String	getContent()	Gets the content of this Lexer.
protected int	getNextSymbol()	Produces individual symbols from content, left to right, as ascii values.
CNumberToken	getNextToken()	Produces next CNumberToken from complex number string.
protected void	putBackSymbol(int sym)	Replaces unneeded symbol back into content string.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ERR_MSG

private static final String ERR_MSG

Error message for unexpected symbol.

See Also:

• Constant Field Values

content

protected String content

Content of the lexer.

Constructor Details

CNumberLexer

public CNumberLexer(String content)

Parameters:

content - - String representation of complex number

Method Details

getContent

public String getContent()

Gets the content of this Lexer.

Returns:

content of Lexer

digit

protected boolean digit(int code)

Parameters:

code - - ascii value of character

Returns:

returns true if character is digit. Otherwise, returns false.

getNextSymbol

protected int getNextSymbol()

Produces individual symbols from content, left to right, as ascii values.

Returns:

Returns ascii value of the next symbol from content. If content is empty then returns -1

putBackSymbol

protected void putBackSymbol(int sym)

Replaces unneeded symbol back into content string. Note: This method should only be used when the programmer is confident the token is not an unexpected token.

Parameters:

sym - - symbol to place back into content string

getNextToken

public CNumberToken getNextToken()

Produces next CNumberToken from complex number string. Also removes this CNumberToken from the string. This method implements a finite automata which describes the legal arrangement of tokens within a complex number.

Returns:

Next CNumberToken in string.

Throws:

RuntimeException - If the string is not a valid representation of a complex number.

error

protected static void error(String message)

Stops execution with an error message

Parameters:

message - - error message to print