org.apache.xpath.compiler
Class Lexer

java.lang.Object
  org.apache.xpath.compiler.Lexer

class Lexer

extends Object

This class is in charge of lexical processing of the XPath expression into tokens.

Field Summary

private Compiler	m_compiler The target XPath.
(package private) PrefixResolver	m_namespaceContext The prefix resolver to map prefixes to namespaces in the XPath.
private int[]	m_patternMap Ignore this, it is going away.
private int	m_patternMapSize Ignore this, it is going away.
(package private) XPathParser	m_processor The XPath processor object.
(package private) static int	TARGETEXTRA This value is added to each element name in the TARGETEXTRA that is a 'target' (right-most top-level element name).

Constructor Summary

(package private)

Lexer(Compiler compiler, PrefixResolver resolver, XPathParser xpathProcessor) Create a Lexer object.

Method Summary

private void	addToTokenQueue(String s) Add a token to the token queue.
(package private) int	getKeywordToken(String key) Given a string, return the corresponding keyword token.
private int	getTokenQueuePosFromMap(int i) Given a map pos, return the corresponding token queue pos.
private int	mapNSTokens(String pat, int startSubstring, int posOfNSSep, int posOfScan) When a seperator token is found, see if there's a element name or the like to map.
private boolean	mapPatternElemPos(int nesting, boolean isStart, boolean isAttrName) Record the current position on the token queue as long as this is a top-level element.
private void	recordTokenString(Vector targetStrings) Record the current token in the passed vector.
private void	resetTokenMark(int mark) Reset token queue mark and m_token to a given position.
(package private) void	tokenize(String pat) Walk through the expression and build a token queue, and a map of the top-level elements.
(package private) void	tokenize(String pat, Vector targetStrings) Walk through the expression and build a token queue, and a map of the top-level elements.

Methods inherited from class java.lang.Object

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

Field Detail

m_compiler

private Compiler m_compiler

The target XPath.

m_namespaceContext

PrefixResolver m_namespaceContext

The prefix resolver to map prefixes to namespaces in the XPath.

m_processor

XPathParser m_processor

The XPath processor object.

TARGETEXTRA

static final int TARGETEXTRA

This value is added to each element name in the TARGETEXTRA that is a 'target' (right-most top-level element name).

See Also:

Constant Field Values

m_patternMap

private int[] m_patternMap

Ignore this, it is going away. This holds a map to the m_tokenQueue that tells where the top-level elements are. It is used for pattern matching so the m_tokenQueue can be walked backwards. Each element that is a 'target', (right-most top level element name) has TARGETEXTRA added to it.

m_patternMapSize

private int m_patternMapSize

Ignore this, it is going away. The number of elements that m_patternMap maps;

Constructor Detail

Lexer

Lexer(Compiler compiler,
      PrefixResolver resolver,
      XPathParser xpathProcessor)

Create a Lexer object.

Parameters:

compiler - The owning compiler for this lexer.

resolver - The prefix resolver for mapping qualified name prefixes to namespace URIs.

xpathProcessor - The parser that is processing strings to opcodes.

Method Detail

tokenize

void tokenize(String pat)
        throws javax.xml.transform.TransformerException

Walk through the expression and build a token queue, and a map of the top-level elements.

Parameters:

pat - XSLT Expression.

Throws:

javax.xml.transform.TransformerException

tokenize

void tokenize(String pat,
              Vector targetStrings)
        throws javax.xml.transform.TransformerException

Walk through the expression and build a token queue, and a map of the top-level elements.

Parameters:

pat - XSLT Expression.

targetStrings - Vector to hold Strings, may be null.

Throws:

javax.xml.transform.TransformerException

mapPatternElemPos

private boolean mapPatternElemPos(int nesting,
                                  boolean isStart,
                                  boolean isAttrName)

Record the current position on the token queue as long as this is a top-level element. Must be called before the next token is added to the m_tokenQueue.

Parameters:

nesting - The nesting count for the pattern element.

isStart - true if this is the start of a pattern.

isAttrName - true if we have determined that this is an attribute name.

Returns:

true if this is the start of a pattern.

getTokenQueuePosFromMap

private int getTokenQueuePosFromMap(int i)

Given a map pos, return the corresponding token queue pos.

Parameters:

i - The index in the m_patternMap.

Returns:

the token queue position.

resetTokenMark

private final void resetTokenMark(int mark)

Reset token queue mark and m_token to a given position.

Parameters:

mark - The new position.

getKeywordToken

final int getKeywordToken(String key)

Given a string, return the corresponding keyword token.

Parameters:

key - The keyword.

Returns:

An opcode value.

recordTokenString

private void recordTokenString(Vector targetStrings)

Record the current token in the passed vector.

Parameters:

targetStrings - Vector of string.

addToTokenQueue

private final void addToTokenQueue(String s)

Add a token to the token queue.

Parameters:

s - The token.

mapNSTokens

private int mapNSTokens(String pat,
                        int startSubstring,
                        int posOfNSSep,
                        int posOfScan)
                 throws javax.xml.transform.TransformerException

When a seperator token is found, see if there's a element name or the like to map.

Parameters:

pat - The XPath name string.

startSubstring - The start of the name string.

posOfNSSep - The position of the namespace seperator (':').

posOfScan - The end of the name index.

Returns:

-1 always.

Throws:

javax.xml.transform.TransformerException