net.sf.saxon.expr
Class ExpressionParser

java.lang.Object
  net.sf.saxon.expr.ExpressionParser

Direct Known Subclasses:

SelectionParser

public class ExpressionParser
extends Object

Parser for XPath expressions and XSLT patterns. This code was originally inspired by James Clark's xt but has been totally rewritten (several times)

Author:

Michael Kay

Nested Class Summary

static class

ExpressionParser.ForClause

Constructor Summary

ExpressionParser()
Create an expression parser

Method Summary

Stack	getRangeVariableStack() Get the range variable stack.
Tokenizer	getTokenizer() Get the tokenizer (the lexical analyzer)
boolean	isCompileWithTracing() Determine whether trace hooks are included in the compiled code.
LocalNameTest	makeLocalNameTest(short nodeType, String localName) Make a LocalNameTest (*:name)
int	makeNameCode(String qname, boolean useDefault) Make a NameCode, using the static context for namespace resolution
int	makeNameCodeSilently(String qname, boolean useDefault) Make a NameCode, using the static context for namespace resolution.
NamespaceTest	makeNamespaceTest(short nodeType, String prefix) Make a NamespaceTest (name:*)
NameTest	makeNameTest(short nodeType, String qname, boolean useDefault) Make a NameTest, using the static context for namespace resolution
StructuredQName	makeStructuredQName(String qname, boolean useDefault) Make a Structured QName, using the static context for namespace resolution
Expression	parse(String expression, int start, int terminator, int lineNumber, StaticContext env) Parse a string representing an expression
Pattern	parsePattern(String pattern, StaticContext env) Parse a string representing an XSLT pattern
SequenceType	parseSequenceType(String input, StaticContext env) Parse a string representing a sequence type
void	setCompileWithTracing(boolean trueOrFalse) Set whether trace hooks are to be included in the compiled code.
void	setRangeVariableStack(Stack stack) Set the range variable stack.
void	setScanOnly(boolean scanOnly) Set that we are parsing in "scan only"

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionParser

public ExpressionParser()

Create an expression parser

Method Detail

setCompileWithTracing

public void setCompileWithTracing(boolean trueOrFalse)

Set whether trace hooks are to be included in the compiled code. To use tracing, it is necessary both to compile the code with trace hooks included, and to supply a TraceListener at run-time

Parameters:

trueOrFalse - true if trace code is to be compiled in, false otherwise

isCompileWithTracing

public boolean isCompileWithTracing()

Determine whether trace hooks are included in the compiled code.

Returns:

true if trace hooks are included, false if not.

getTokenizer

public Tokenizer getTokenizer()

Get the tokenizer (the lexical analyzer)

Returns:

the tokenizer (the lexical analyzer)

parse

public Expression parse(String expression,
                        int start,
                        int terminator,
                        int lineNumber,
                        StaticContext env)
                 throws XPathException

Parse a string representing an expression

Parameters:

expression - the expression expressed as a String

start - offset within the string where parsing is to start

terminator - character to treat as terminating the expression

lineNumber - location of the start of the expression, for diagnostics

env - the static context for the expression

Returns:

an Expression object representing the result of parsing

Throws:

XPathException - if the expression contains a syntax error

parsePattern

public Pattern parsePattern(String pattern,
                            StaticContext env)
                     throws XPathException

Parse a string representing an XSLT pattern

Parameters:

pattern - the pattern expressed as a String

env - the static context for the pattern

Returns:

a Pattern object representing the result of parsing

Throws:

XPathException - if the pattern contains a syntax error

parseSequenceType

public SequenceType parseSequenceType(String input,
                                      StaticContext env)
                               throws XPathException

Parse a string representing a sequence type

Parameters:

input - the string, which should conform to the XPath SequenceType production

env - the static context

Returns:

a SequenceType object representing the type

Throws:

XPathException - if any error is encountered

getRangeVariableStack

public Stack getRangeVariableStack()

Get the range variable stack. Used when parsing a nested subexpression inside an attribute constructor

Returns:

the stack used for locally-declared variables

setRangeVariableStack

public void setRangeVariableStack(Stack stack)

Set the range variable stack. Used when parsing a nested subexpression inside an attribute constructor.

Parameters:

stack - the stack to be used for local variables declared within the expression

makeNameCode

public final int makeNameCode(String qname,
                              boolean useDefault)
                       throws XPathException

Make a NameCode, using the static context for namespace resolution

Parameters:

qname - The name as written, in the form "[prefix:]localname"

useDefault - Defines the action when there is no prefix. If true, use the default namespace URI for element names. If false, use no namespace URI (as for attribute names).

Returns:

the namecode, which can be used to identify this name in the name pool

Throws:

XPathException - if the name is invalid, or the prefix undeclared

makeNameCodeSilently

public final int makeNameCodeSilently(String qname,
                                      boolean useDefault)
                               throws XPathException,
                                      QNameException

Make a NameCode, using the static context for namespace resolution. This variant of the method does not call "grumble" to report any errors to the ErrorListener, it only reports errors by throwing exceptions. This allows the caller to control the message output.

Parameters:

qname - The name as written, in the form "[prefix:]localname"

useDefault - Defines the action when there is no prefix. If true, use the default namespace URI for element names. If false, use no namespace URI (as for attribute names).

Returns:

the namecode, which can be used to identify this name in the name pool

Throws:

XPathException - if the name is invalid, or the prefix undeclared

QNameException

makeStructuredQName

public final StructuredQName makeStructuredQName(String qname,
                                                 boolean useDefault)
                                          throws XPathException

Make a Structured QName, using the static context for namespace resolution

Parameters:

qname - The name as written, in the form "[prefix:]localname"

useDefault - Defines the action when there is no prefix. If true, use the default namespace URI for element names. If false, use no namespace URI (as for attribute names).

Returns:

the namecode, which can be used to identify this name in the name pool

Throws:

XPathException - if the name is invalid, or the prefix undeclared

makeNameTest

public NameTest makeNameTest(short nodeType,
                             String qname,
                             boolean useDefault)
                      throws XPathException

Make a NameTest, using the static context for namespace resolution

Parameters:

nodeType - the type of node required (identified by a constant in class Type)

qname - the lexical QName of the required node

useDefault - true if the default namespace should be used when the QName is unprefixed

Returns:

a NameTest, representing a pattern that tests for a node of a given node kind and a given name

Throws:

XPathException - if the QName is invalid

makeNamespaceTest

public NamespaceTest makeNamespaceTest(short nodeType,
                                       String prefix)
                                throws XPathException

Make a NamespaceTest (name:*)

Parameters:

nodeType - integer code identifying the type of node required

prefix - the namespace prefix

Returns:

the NamespaceTest, a pattern that matches all nodes in this namespace

Throws:

XPathException - if the namespace prefix is not declared

makeLocalNameTest

public LocalNameTest makeLocalNameTest(short nodeType,
                                       String localName)
                                throws XPathException

Make a LocalNameTest (*:name)

Parameters:

nodeType - the kind of node to be matched

localName - the requred local name

Returns:

a LocalNameTest, a pattern which matches all nodes of a given local name, regardless of namespace

Throws:

XPathException - if the local name is invalid

setScanOnly

public void setScanOnly(boolean scanOnly)

Set that we are parsing in "scan only"

Parameters:

scanOnly - true if parsing is to proceed in scan-only mode. In this mode namespace bindings are not yet known, so no attempt is made to look up namespace prefixes.