net.sf.saxon.functions

Class Matches

Implemented Interfaces:
EvaluableItem, InstructionInfoProvider, SequenceIterable, Serializable, SourceLocator

public class Matches
extends SystemFunction

This class implements the matches() function for regular expression matching

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunction

operation

Fields inherited from class net.sf.saxon.expr.FunctionCall

argument

Fields inherited from class net.sf.saxon.expr.Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD, locationId, staticProperties

Method Summary

Item
evaluateItem(XPathContext c)
Evaluate the matches() function to give a Boolean value.
RegularExpression
getCompiledRegularExpression()
Get the compiled regular expression, returning null if the regex has not been compiled
Expression
optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
Expression
simplify(ExpressionVisitor visitor)
Simplify and validate.
static RegularExpression
tryToCompile(Expression[] args, int patternArg, int flagsArg, StaticContext env)
Try to precompile the arguments to the function.

Methods inherited from class net.sf.saxon.functions.SystemFunction

addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

Methods inherited from class net.sf.saxon.expr.FunctionCall

addExternalFunctionCallToPathMap, checkArgumentCount, checkArguments, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, optimize, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression

addToPathMap, adoptChildExpression, checkPermittedContents, computeCardinality, computeDependencies, computeSpecialProperties, computeStaticProperties, copy, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, explain, findParentOf, getCardinality, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getItemType, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, iterateSubExpressions, markTailFunctionCalls, optimize, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Method Details

evaluateItem

public Item evaluateItem(XPathContext c)
            throws XPathException
Evaluate the matches() function to give a Boolean value.
Specified by:
evaluateItem in interface EvaluableItem
Overrides:
evaluateItem in interface Expression
Parameters:
c - The dynamic evaluation context
Returns:
the result as a BooleanValue, or null to indicate the empty sequence
Throws:
XPathException - on an error

getCompiledRegularExpression

public RegularExpression getCompiledRegularExpression()
Get the compiled regular expression, returning null if the regex has not been compiled
Returns:
the compiled regular expression, or null

optimize

public Expression optimize(ExpressionVisitor visitor,
                           ItemType contextItemType)
            throws XPathException
Perform optimisation of an expression and its subexpressions.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:
optimize in interface SystemFunction
Parameters:
visitor - an expression visitor
contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
Returns:
the original expression, rewritten if appropriate to optimize execution
Throws:
XPathException - if an error is discovered during this phase (typically a type error)

simplify

public Expression simplify(ExpressionVisitor visitor)
            throws XPathException
Simplify and validate. This is a pure function so it can be simplified in advance if the arguments are known
Overrides:
simplify in interface FunctionCall
Parameters:
visitor - an expression visitor
Returns:
the simplified expression
Throws:
XPathException - if any error is found (e.g. invalid regular expression)

tryToCompile

public static RegularExpression tryToCompile(Expression[] args,
                                             int patternArg,
                                             int flagsArg,
                                             StaticContext env)
            throws XPathException
Try to precompile the arguments to the function. This method is shared by the implementations of the three XPath functions matches(), replace(), and tokenize().
Parameters:
args - the supplied arguments to the function, as an array
patternArg - the position of the argument containing the regular expression
flagsArg - the position of the argument containing the flags
env - the static context
Returns:
the compiled regular expression, or null indicating that the information is not available statically so it cannot be precompiled
Throws:
XPathException - if any failure occurs, in particular, if the regular expression is invalid