com.saxonica.functions.hof

Class CoercedFunction

java.lang.Object

net.sf.saxon.om.AbstractItem

com.saxonica.functions.hof.AbstractFunctionItem

com.saxonica.functions.hof.CoercedFunction

All Implemented Interfaces:

PullEvent, Callable, FunctionItem, GroundedValue, Item, Sequence

public class CoercedFunction
extends AbstractFunctionItem

A function item obtained by coercing a supplied function; this adds a wrapper to perform dynamic type checking of the arguments in any call, and type checking of the result.

Constructor Summary

Constructors

Constructor and Description
CoercedFunction(FunctionItem targetFunction) Create a CoercedFunction as a wrapper around a target function

Method Summary

Methods

Modifier and Type	Method and Description
Sequence	call(XPathContext context, Sequence[] args) Invoke the function
static CoercedFunction	coerce(FunctionItem suppliedFunction, SpecificFunctionType requiredType, RoleLocator role, TypeCheckerEnvironment visitor) Factory method to create a CoercedFunction with a given type, for a given targetFunction.
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
void	setArgumentConverter(int arg, Expression converter) Set the argument converter for one argument
void	setResultConverter(Expression converter) Set the converter used to process the returned value
void	setStackFrameMap(SlotManager stackFrame) Set the stack frame map identifying the arguments for conversion
void	typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) Type check the function (may modify it by adding code for converting the arguments)

Methods inherited from class com.saxonica.functions.hof.AbstractFunctionItem

deepEquals, effectiveBooleanValue, explain, getStringValue, getStringValueCS, getTypedValue, optimize, simplify

Methods inherited from class net.sf.saxon.om.AbstractItem

getLength, head, itemAt, iterate, reduce, subsequence

Methods inherited from class java.lang.Object

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

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

getLength, itemAt, reduce, subsequence

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

head, iterate

Constructor Detail

CoercedFunction

public CoercedFunction(FunctionItem targetFunction)

Create a CoercedFunction as a wrapper around a target function

Parameters:

targetFunction - the function to be wrapped by a type-checking layer

Method Detail

setArgumentConverter

public void setArgumentConverter(int arg,
                        Expression converter)

Set the argument converter for one argument

Parameters:

arg - identifies the argument to be converted

converter - the expression used to perform the conversion

setResultConverter

public void setResultConverter(Expression converter)

Set the converter used to process the returned value

Parameters:

converter - the expression used to perform the conversion

setStackFrameMap

public void setStackFrameMap(SlotManager stackFrame)

Set the stack frame map identifying the arguments for conversion

Parameters:

stackFrame -

typeCheck

public void typeCheck(ExpressionVisitor visitor,
             ExpressionVisitor.ContextItemType contextItemType)
               throws XPathException

Type check the function (may modify it by adding code for converting the arguments)

Overrides:

typeCheck in class AbstractFunctionItem

Parameters:

visitor - the expression visitor, supplies context information

contextItemType - the context item type at the point where the function definition appears

Throws:

XPathException

getFunctionItemType

public FunctionItemType getFunctionItemType(TypeHierarchy th)

Get the item type of the function item

Parameters:

th -

Returns:

the function item's type

getFunctionName

public StructuredQName getFunctionName()

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

Returns:

null indicating that this is an anonymous inline function

getArity

public int getArity()

Get the arity of the function

Returns:

the number of arguments in the function signature

call

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

Invoke the function

Parameters:

context - the XPath dynamic evaluation context

args - the actual arguments to be supplied

Returns:

the result of invoking the function

Throws:

XPathException

coerce

public static CoercedFunction coerce(FunctionItem suppliedFunction,
                     SpecificFunctionType requiredType,
                     RoleLocator role,
                     TypeCheckerEnvironment visitor)
                              throws XPathException

Factory method to create a CoercedFunction with a given type, for a given targetFunction. It is assumed that we have already established that coercion is needed

Throws:

XPathException