com.novell.xml.xpath
Class Scanner

java.lang.Object
  com.novell.xml.xpath.Scanner

public class Scanner

extends Object

class to scan and separate a string containing an XPath expression into lexical tokens

See Also:

Token

Field Summary

protected static char

EAT_CHAR

Constructor Summary

Scanner(String string)
Construct a scanner for the passed expression

Method Summary

protected void	appendToken(Token token) Append a token to the result tokens.
protected boolean	checkOpNameMulOpState() Check the preceding Token type to see if an operator name ("div", "mod", "and", "or") or the multiply operator ("*") should be recognized as such
protected void	done() Allow a derived class to finish processing when the end of the input string is reached.
protected char	getNextChar() Get next character from input string
protected char	getNextXMLChar() Return next non-whitespace XML character from input string
protected void	handleChar(char scanChar) Add appropriate token for text starting with passed character This will continue scanning ahead if necessary, and may check the previous Token
protected void	handleLiteral(char startQuote) Create a LiteralToken for the literal text enclosed in single or double quotes
protected void	handleNumber(char startChar) Create a NumberToken from scanned text
protected void	handleQName(com.novell.xml.xpath.QName qName) Construct appropriate token based on an XML QName This will add a WildcardNameToken, FunctionNameToken, NodeTypeToken, or OperatorToken depending on characters and context
protected boolean	isDigit(char c) Determine if passed char is a digit
protected Token	lastToken() Return the last token appended to the result tokens.
protected void	popPos() Restore saved position in expression string
protected char	prescanChar(char scanChar) Perform any non-XPath processing for this character.
protected void	pushPos() Remember current position in expression string
protected void	reset() reset scanner to rescan string
protected Token[]	returnTokens() Return the result tokens as an array of tokens.
Token[]	scan() Return lexical tokens for expression
protected String	scanNCName(char firstChar) scan all characters making up an XML NCName
static double	scanNumber(String string) Scan a string and return the numeric value if string matches the XPath Number production.
protected com.novell.xml.xpath.QName	scanQName(char firstChar) scan all characters making up an XML QName
protected void	tossPos() Throw away remembered position in expression string

Methods inherited from class java.lang.Object

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

Field Detail

EAT_CHAR

protected static final char EAT_CHAR

See Also:

Constant Field Values

Constructor Detail

Scanner

public Scanner(String string)

Construct a scanner for the passed expression

Parameters:

string - XPath expression

Method Detail

scan

public Token[] scan()
             throws XPathParserException

Return lexical tokens for expression

Returns:

array of Token objects

Throws:

java.lang.XPathParserException

XPathParserException

scanNumber

public static double scanNumber(String string)

Scan a string and return the numeric value if string matches the XPath Number production.

Parameters:

string - The string to scan.

Returns:

The numeric value, or NaN if string isn't a number.

prescanChar

protected char prescanChar(char scanChar)

Perform any non-XPath processing for this character. Return true if character should then be processed normally as part of an XPath expression. This is intended primarily for XSLT AttributeValueTemplate scanning.

Parameters:

scanChar - The character being scanned.

Returns:

True if char should be processed further.

done

protected void done()

Allow a derived class to finish processing when the end of the input string is reached.

handleQName

protected void handleQName(com.novell.xml.xpath.QName qName)
                    throws XPathParserException

Construct appropriate token based on an XML QName This will add a WildcardNameToken, FunctionNameToken, NodeTypeToken, or OperatorToken depending on characters and context

Parameters:

qName - object representing QName

Throws:

java.lang.XPathParserException

XPathParserException

handleChar

protected void handleChar(char scanChar)
                   throws XPathParserException

Add appropriate token for text starting with passed character This will continue scanning ahead if necessary, and may check the previous Token

Parameters:

scanChar - character scanned

Throws:

java.lang.XPathParserException

XPathParserException

handleLiteral

protected void handleLiteral(char startQuote)

Create a LiteralToken for the literal text enclosed in single or double quotes

Parameters:

startQuote - scanned quote char '\'' or '"'

handleNumber

protected void handleNumber(char startChar)

Create a NumberToken from scanned text

Parameters:

startChar - Either a digit ('0'-'9') or a decimal point ('.')

checkOpNameMulOpState

protected boolean checkOpNameMulOpState()

Check the preceding Token type to see if an operator name ("div", "mod", "and", "or") or the multiply operator ("*") should be recognized as such

Returns:

true if token being scanned should be recognized as an operator

scanQName

protected com.novell.xml.xpath.QName scanQName(char firstChar)

scan all characters making up an XML QName

Parameters:

firstChar - XML start name character already scanned

Returns:

object representing XML QName

See Also:

XML Names

scanNCName

protected String scanNCName(char firstChar)

scan all characters making up an XML NCName

Parameters:

firstChar - XML start name character already scanned

Returns:

string containing XML NCName

See Also:

XML Names

getNextXMLChar

protected char getNextXMLChar()

Return next non-whitespace XML character from input string

Returns:

character, or 0 if no more chars in string

getNextChar

protected char getNextChar()

Get next character from input string

Returns:

character, or 0 if no more characters

isDigit

protected boolean isDigit(char c)

Determine if passed char is a digit

Parameters:

c - char to check

Returns:

true if passed char in in range '0' to '9' inclusive

reset

protected void reset()

reset scanner to rescan string

pushPos

protected void pushPos()

Remember current position in expression string

tossPos

protected void tossPos()

Throw away remembered position in expression string

See Also:

pushPos()

popPos

protected void popPos()

Restore saved position in expression string

See Also:

pushPos()

appendToken

protected final void appendToken(Token token)

Append a token to the result tokens.

Parameters:

token - The token to append.

lastToken

protected final Token lastToken()

Return the last token appended to the result tokens.

Returns:

The last Token appended to the result tokens.

returnTokens

protected Token[] returnTokens()

Return the result tokens as an array of tokens.

Returns:

An array of Token objects.