net.sf.saxon.om

Interface FunctionItem

All Superinterfaces:

Callable, GroundedValue, Item, PullEvent, Sequence

All Known Subinterfaces:

MapItem

All Known Implementing Classes:

AbstractFunctionItem, AtomicConstructorFunctionItem, CallableFunctionItem, CoercedFunction, CurriedFunction, ImmutableMap, RangeKey, SingletonMap, UserFunctionItem

public interface FunctionItem
extends Item, Callable, GroundedValue

XDM 3.0 introduces a third kind of item, beyond nodes and atomic values: the function item. Function items implement this marker interface. The actual implementation class is in Saxon-PE and Saxon-EE only.

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] args) Invoke the function
boolean	deepEquals(FunctionItem other, XPathContext context, AtomicComparer comparer, int flags) Test whether this FunctionItem is deep-equal to another function item, under the rules of the deep-equal function
int	getArity() Get the arity of the function
FunctionItemType	getFunctionItemType(TypeHierarchy th) Get the item type of the function item
StructuredQName	getFunctionName() Get the name of the function, or null if it is anonymous

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

getStringValue, getStringValueCS

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

effectiveBooleanValue, getLength, getStringValue, getStringValueCS, itemAt, reduce, subsequence

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

head, iterate

Method Detail

getFunctionItemType

FunctionItemType getFunctionItemType(TypeHierarchy th)

Get the item type of the function item

Parameters:

th - the type hierarchy cache

Returns:

the function item's type

getFunctionName

StructuredQName getFunctionName()

Get the name of the function, or null if it is anonymous

Returns:

the function name, or null for an anonymous inline function

getArity

int getArity()

Get the arity of the function

Returns:

the number of arguments in the function signature

call

Sequence call(XPathContext context,
            Sequence[] args)
              throws XPathException

Invoke the function

Specified by:

call in interface Callable

Parameters:

context - the XPath dynamic evaluation context

args - the actual arguments to be supplied

Returns:

the result of invoking the function

Throws:

XPathException - if a dynamic error occurs within the function

deepEquals

boolean deepEquals(FunctionItem other,
                 XPathContext context,
                 AtomicComparer comparer,
                 int flags)
                   throws XPathException

Test whether this FunctionItem is deep-equal to another function item, under the rules of the deep-equal function

Parameters:

other - the other function item

context - the dynamic evaluation context

comparer - the object to perform the comparison

flags - options for how the comparison is performed

Returns:

true if the two function items are deep-equal

Throws:

XPathException - if the comparison cannot be performed