Package net.sf.saxon.s9api

Class XdmFunctionItem

java.lang.Object

net.sf.saxon.s9api.XdmValue

net.sf.saxon.s9api.XdmItem

net.sf.saxon.s9api.XdmFunctionItem

All Implemented Interfaces:

java.lang.Iterable<XdmItem>

Direct Known Subclasses:

XdmArray, XdmMap

public class XdmFunctionItem
extends XdmItem

The class XdmFunctionItem represents a function item

Constructor Summary

Constructors

Constructor	Description
XdmFunctionItem(Function fi)	Create an XdmFunctionItem that wraps a supplied Function.

Method Summary

Modifier and Type	Method	Description
java.util.function.Function<? super XdmValue,? extends XdmValue>	asFunction(Processor processor)	Get an equivalent Java Function object representing this XdmFunction.
Step<XdmItem>	asStep(Processor processor)	Get an equivalent Step object representing this XdmFunction.
XdmValue	call(Processor processor, XdmValue... arguments)	Call the function
int	getArity()	Get the arity of the function
QName	getName()	Get the name of the function
static XdmFunctionItem	getSystemFunction(Processor processor, QName name, int arity)	Get a system function.
boolean	isAtomicValue()	Determine whether the item is an atomic value

Methods inherited from class net.sf.saxon.s9api.XdmItem

asMap, getStringValue, getUnderlyingValue, getUnicodeStringValue, isNode, matches, size, stream, wrapItem, wrapItem, wrapItem

Methods inherited from class net.sf.saxon.s9api.XdmValue

append, documentOrder, isEmpty, itemAt, iterator, makeSequence, makeValue, select, subsequence, toString, wrap, wrap

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

XdmFunctionItem

public XdmFunctionItem(Function fi)

Create an XdmFunctionItem that wraps a supplied Function. This method is primarily for internal use, though it is also available to applications that manipulate data using lower-level Saxon interfaces.

Parameters:

fi - the function value to be wrapped.

Method Detail

getName

public QName getName()

Get the name of the function

Returns:

the function name, as a QName, or null for an anonymous inline function item

getArity

public int getArity()

Get the arity of the function

Returns:

the arity of the function, that is, the number of arguments in the function's signature

isAtomicValue

public boolean isAtomicValue()

Determine whether the item is an atomic value

Overrides:

isAtomicValue in class XdmItem

Returns:

false, the item is not an atomic value, it is a function item

getSystemFunction

public static XdmFunctionItem getSystemFunction(Processor processor,
                                                QName name,
                                                int arity)
                                         throws SaxonApiException

Get a system function. This can be any function defined in XPath 3.1 functions and operators, including functions in the math, map, and array namespaces. It can also be a Saxon extension function, provided a licensed Processor is used.

Parameters:

processor - the processor

name - the name of the requested function

arity - the arity of the requested function

Returns:

the requested function, or null if there is no such function. Note that some functions (those with particular context dependencies) may be unsuitable for dynamic calling.

Throws:

SaxonApiException - No longer thrown, but remains in the method signature for backwards compatibility

asFunction

public java.util.function.Function<? super XdmValue,? extends XdmValue> asFunction(Processor processor)

Get an equivalent Java Function object representing this XdmFunction. This is possible only for arity-1 functions.

Parameters:

processor - the processor

Returns:

a Java Function. This takes an XdmValue as its argument, and returns the function result in the form of an XdmValue. The Function throws an unchecked exception if evaluation fails

Throws:

java.lang.IllegalStateException - if the arity of the function is not one (1).

asStep

public Step<XdmItem> asStep(Processor processor)

Get an equivalent Step object representing this XdmFunction. This is possible only for arity-1 functions.

Parameters:

processor - the processor

Returns:

a Step. This takes an XdmItem as its argument, and returns the function result in the form of an XdmStream. The Function throws an unchecked exception if evaluation fails

Throws:

java.lang.IllegalStateException - if the arity of the function is not one (1).

call

public XdmValue call(Processor processor,
                     XdmValue... arguments)
              throws SaxonApiException

Call the function

Parameters:

arguments - the values to be supplied as arguments to the function. The "function conversion rules" will be applied to convert the arguments to the required type when necessary.

processor - the s9api Processor

Returns:

the result of calling the function

Throws:

SaxonApiException - if an error is detected