Package com.saxonica.functions.extfn

Class Leading

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

com.saxonica.functions.extfn.Leading

All Implemented Interfaces:

Callable, FunctionItem, GroundedValue, Item, Sequence

public class Leading
extends SystemFunction

This class implements the saxon:leading() extension functions.

The first argument is a sequence S, the second a function F (defaulting to fn:data). The function returns the item or items I in the input sequence S up to and excluding the first one for which F(I) returns false.

Constructor Summary

Constructors

Constructor	Description
Leading()

Method Summary

Modifier and Type	Method	Description
Sequence	call(XPathContext context, Sequence[] arguments)	Evaluate this function call at run-time

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

dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, exportAttributes, fixArguments, getArity, getCardinality, getContextNode, getDescription, getDetails, getElaborator, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, getStreamerName, getUniStringArg, hashCode, importAttributes, isSequenceVariadic, isTrustedResultType, makeCall, makeFunction, makeFunction40, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, toShortString, toString, typeCheckCaller

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

atomize, deepEqual40, deepEquals, effectiveBooleanValue, getAnnotations, getUnicodeStringValue, isArray, isMap, makeNewContext, simplify, typeCheck

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.FunctionItem

getGenre

Methods inherited from interface net.sf.saxon.om.GroundedValue

asIterable, concatenate, containsNode, materialize

Methods inherited from interface net.sf.saxon.om.Item

getLength, getStringValue, head, isStreamed, itemAt, iterate, reduce, subsequence

Methods inherited from interface net.sf.saxon.om.Sequence

makeRepeatable

Constructor Detail

Leading

public Leading()

Method Detail

call

public Sequence call(XPathContext context,
                     Sequence[] arguments)
              throws XPathException

Evaluate this function call at run-time

Parameters:

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.

Returns:

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()

Throws:

XPathException - if a dynamic error occurs during evaluation of the function. The Saxon run-time code will add information about the error location.