net.sf.saxon.functions
Class Matches

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.Matches

All Implemented Interfaces:

Serializable, SourceLocator, EvaluableItem, SequenceIterable, InstructionInfoProvider

public class Matches
extends SystemFunction

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

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

Matches()

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

addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, getDetails, getErrorCodeForTypeErrors, getItemType, makeSystemFunction, setDetails

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

addExternalFunctionCallToPathMap, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, toString, typeCheck

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

addToPathMap, adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, effectiveBooleanValue, evaluateAsString, explain, findParentOf, getCardinality, getColumnNumber, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, iterate, iterateEvents, markTailFunctionCalls, process, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Matches

public Matches()

Method Detail

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 class FunctionCall

Parameters:

visitor - an expression visitor

Returns:

the simplified expression

Throws:

XPathException - if any error is found (e.g. invalid regular expression)

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 class 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)

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

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 class 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

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