Class CompileXPath

  • All Implemented Interfaces:
    Callable, Function, GroundedValue, Item, Sequence

    public class CompileXPath
    extends SystemFunction
    This class implements the saxon:compile-XPath() extension function, which is specially-recognized by the system because it needs access to parts of the static context.

    The compile-XPath() extension function compiles an XPath expression to a SEF representation. It was originally defined for Saxon-JS to allow free-standing compilation and execution of dynamic XPath expressions in the browser; this is a back-port to Saxon-Java so that the same code can be executed in either environment, which facilitates testing.

    • Constructor Detail

      • CompileXPath

        public CompileXPath()
    • Method Detail

      • call

        public MapItem call​(XPathContext context,
                            Sequence[] arguments)
                     throws XPathException
        Evaluate this function call at run-time
        context - The XPath dynamic evaluation context
        arguments - The values of the arguments to the function call. Each argument value (which is in general a sequence) is supplied in the form of an iterator over the items in the sequence. If required, the supplied sequence can be materialized by calling, for example, new SequenceExtent(arguments[i]). If the argument is always a singleton, then the single item may be obtained by calling arguments[i].next(). The implementation is not obliged to read all the items in each SequenceIterator if they are not required to compute the result; but if any SequenceIterator is not read to completion, it is good practice to call its close() method.
        an iterator over the results of the function. If the result is a single item, it can be returned in the form of a SingletonIterator. If the result is an empty sequence, the method should return EmptyIterator.getInstance()
        XPathException - if a dynamic error occurs during evaluation of the function. The Saxon run-time code will add information about the error location.
      • make

        public static Expression make​(java.lang.String expression,
                                      StaticContext env,
                                      int start,
                                      int terminator,
                                      CodeInjector codeInjector,
                                      boolean inCatch)
                               throws XPathException
        Upgraded from ExpressionTool.make() to permit 'in-catch' conversion of error variables to calls on saxon:dynamic-error-info()

        Parse an XPath expression. This performs the basic analysis of the expression against the grammar, it binds variable references and function calls to variable definitions and function definitions, and it performs context-independent expression rewriting for optimization purposes.

        expression - The expression (as a character string)
        env - An object giving information about the compile-time context of the expression
        start - position of the first significant character in the expression
        terminator - The token that marks the end of this expression; typically Token.EOF, but may for example be a right curly brace
        codeInjector - true allows injection of tracing, debugging, or performance monitoring code; null if not required
        inCatch - The Xpath is considered to be in the context of an xsl:catch
        an object of type Expression
        XPathException - if the expression contains a static error