com.saxonica.hof
Class FunctionType

java.lang.Object
  net.sf.saxon.type.AnyFunctionType
      com.saxonica.hof.FunctionType

All Implemented Interfaces:

Serializable, FunctionItemType, ItemType

public class FunctionType
extends AnyFunctionType

An instance of this class represents a specific function item type, for example function(xs:int) as xs:boolean

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.type.AnyFunctionType

ANY_FUNCTION, SINGLE_FUNCTION

Constructor Summary

FunctionType(SequenceType[] argTypes, SequenceType resultType)

Method Summary

boolean	equals(Object other) Test whether this function type equals another function type
SequenceType[]	getArgumentTypes() Get the argument types
int	getArity() Get the arity (number of arguments) of this function type
SequenceType	getResultType() Get the result type
ItemType	getSuperType(TypeHierarchy th) Get the type from which this item type is derived by restriction.
Expression	makeFunctionSequenceCoercer(Expression exp, RoleLocator role, ExpressionVisitor visitor) Create an expression whose effect is to apply function coercion to coerce a function from this type to another type
boolean	matchesItem(Item item, boolean allowURIPromotion, Configuration config) Test whether a given item conforms to this type
int	relationship(FunctionItemType other, TypeHierarchy th) Determine the relationship of one function item type to another
String	toString() Produce a representation of this type name for use in error messages.
String	toString(NamePool pool) Produce a representation of this type name for use in error messages.

Methods inherited from class net.sf.saxon.type.AnyFunctionType

getAtomizedItemType, getInstance, getPrimitiveItemType, getPrimitiveType, isAtomicType, isAtomizable

Methods inherited from class java.lang.Object

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

Constructor Detail

FunctionType

public FunctionType(SequenceType[] argTypes,
                    SequenceType resultType)

Method Detail

getArity

public int getArity()

Get the arity (number of arguments) of this function type

Returns:

the number of argument types in the function signature

getArgumentTypes

public SequenceType[] getArgumentTypes()

Get the argument types

Returns:

the list of argument types

getResultType

public SequenceType getResultType()

Get the result type

Returns:

the result type

matchesItem

public boolean matchesItem(Item item,
                           boolean allowURIPromotion,
                           Configuration config)

Test whether a given item conforms to this type

Specified by:

matchesItem in interface ItemType

Overrides:

matchesItem in class AnyFunctionType

Parameters:

item - The item to be tested

allowURIPromotion -

config -

Returns:

true if the item is an instance of this type; false otherwise

getSuperType

public ItemType getSuperType(TypeHierarchy th)

Get the type from which this item type is derived by restriction. This is the supertype in the XPath type heirarchy, as distinct from the Schema base type: this means that the supertype of xs:boolean is xs:anyAtomicType, whose supertype is item() (rather than xs:anySimpleType).

In fact the concept of "supertype" is not really well-defined, because the types form a lattice rather than a hierarchy. The only real requirement on this function is that it returns a type that strictly subsumes this type, ideally as narrowly as possible.

Specified by:

getSuperType in interface ItemType

Overrides:

getSuperType in class AnyFunctionType

Parameters:

th - the type hierarchy cache

Returns:

the supertype, or null if this type is item()

toString

public String toString(NamePool pool)

Produce a representation of this type name for use in error messages. Where this is a QName, it will use conventional prefixes

Specified by:

toString in interface ItemType

Overrides:

toString in class AnyFunctionType

Parameters:

pool - the name pool

Returns:

a string representation of the type, in notation resembling but not necessarily identical to XPath syntax

toString

public String toString()

Produce a representation of this type name for use in error messages.

Overrides:

toString in class AnyFunctionType

Returns:

a string representation of the type, in notation resembling but not necessarily identical to XPath syntax

equals

public boolean equals(Object other)

Test whether this function type equals another function type

Overrides:

equals in class Object

relationship

public int relationship(FunctionItemType other,
                        TypeHierarchy th)

Determine the relationship of one function item type to another

Specified by:

relationship in interface FunctionItemType

Overrides:

relationship in class AnyFunctionType

Returns:

for example TypeHierarchy.SUBSUMES, TypeHierarchy.SAME_TYPE

makeFunctionSequenceCoercer

public Expression makeFunctionSequenceCoercer(Expression exp,
                                              RoleLocator role,
                                              ExpressionVisitor visitor)
                                       throws XPathException

Description copied from class: AnyFunctionType

Create an expression whose effect is to apply function coercion to coerce a function from this type to another type

Specified by:

makeFunctionSequenceCoercer in interface FunctionItemType

Overrides:

makeFunctionSequenceCoercer in class AnyFunctionType

Parameters:

exp - the expression that delivers the supplied sequence of function items (the ones in need of coercion)

role - information for use in diagnostics

visitor - the expression visitor, supplies context information

Returns:

the coerced function, a function that calls the original function after checking the parameters

Throws:

XPathException