net.sf.saxon.functions
public class Matches extends SystemFunction
Method Summary | |
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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.
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Expression | simplify(ExpressionVisitor visitor)
Simplify and validate.
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static RegularExpression | tryToCompile(Expression[] args, int patternArg, int flagsArg, StaticContext env)
Try to precompile the arguments to the function. |
Parameters: c The dynamic evaluation context
Returns: the result as a BooleanValue, or null to indicate the empty sequence
Throws: XPathException on an error
Returns: the compiled regular expression, or null
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.
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 ITEM_TYPE
Returns: the original expression, rewritten if appropriate to optimize execution
Throws: net.sf.saxon.trans.XPathException if an error is discovered during this phase (typically a type error)
Parameters: visitor an expression visitor
Returns: the simplified expression
Throws: XPathException if any error is found (e.g. invalid regular expression)
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