org.treetank.service.xml.xpath.parser

Class XPathScanner

java.lang.Object

org.treetank.service.xml.xpath.parser.XPathScanner

public final class XPathScanner
extends Object

XPathScanner

Lexical scanner to extract tokens from the query.

This scanner is used to interpret the query. It reads the the query string char by char and specifies the type of the input and creates a token for every logic text unit.

Constructor Summary

Constructors

Constructor and Description
XPathScanner(String mQuery) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
String	begin() Returns the beginning of a query that has already been scanned.
int	getPos() Return the current cursor position in the query.
IXPathToken	lookUpTokens(int paramNext) Return the token that will be returned by the scanner after the call of nextToken(), without changing the internal state of the scanner.
IXPathToken	nextToken() Reads the string char by char and returns one token by call.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

XPathScanner

public XPathScanner(String mQuery)

Constructor. Initializes the internal state. Receives query and adds a end mark to it.

Parameters:

mQuery - the query to scan

Method Detail

nextToken

public IXPathToken nextToken()

Reads the string char by char and returns one token by call. The scanning starts in the start state, if not further specified before, and specifies the next scanner state and the type of the future token according to its first char. As soon as the current char does not fit the conditions for the current token type, the token is generated and returned.

Returns:

token The new token.

lookUpTokens

public IXPathToken lookUpTokens(int paramNext)

Return the token that will be returned by the scanner after the call of nextToken(), without changing the internal state of the scanner.

Parameters:

paramNext - number of next tokens to be read

Returns:

token that will be read after calling nextToken()

begin

public String begin()

Returns the beginning of a query that has already been scanned. This can be used by the client e.g. for error messages in case of unexpected token occurs.

Returns:

string so far

getPos

public int getPos()

Return the current cursor position in the query.

Returns:

current position of the cursor

toString

public String toString()

Overrides:

toString in class Object