com.saxonica.hof
Class CoercedFunction

java.lang.Object
  com.saxonica.hof.AbstractFunctionItem
      com.saxonica.hof.CoercedFunction

All Implemented Interfaces:

Serializable, PullEvent, FunctionItem, Item, ValueRepresentation

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.

See Also:

Serialized Form

Field Summary

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Constructor Summary

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

Method Summary

static CoercedFunction	coerce(FunctionItem suppliedFunction, FunctionType requiredType, RoleLocator role, ExpressionVisitor 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() Get the item type of the function item
StructuredQName	getFunctionName() Get the name of the function, or null if it is anonymous
ValueRepresentation	invoke(ValueRepresentation[] args, XPathContext context) Invoke the function
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

Methods inherited from class com.saxonica.hof.AbstractFunctionItem

bind, curry, explain, getStringValue, getStringValueCS, getTypedValue, optimize, typeCheck

Methods inherited from class java.lang.Object

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

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 -

getFunctionItemType

public FunctionItemType getFunctionItemType()

Get the item type of the function item

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

invoke

public ValueRepresentation invoke(ValueRepresentation[] args,
                                  XPathContext context)
                           throws XPathException

Invoke the function

Parameters:

args - the actual arguments to be supplied

context - the XPath dynamic evaluation context

Returns:

the result of invoking the function

Throws:

XPathException

coerce

public static CoercedFunction coerce(FunctionItem suppliedFunction,
                                     FunctionType requiredType,
                                     RoleLocator role,
                                     ExpressionVisitor 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