## com.saxonica.functions.hof
Class FunctionType

    java.lang.Object
      net.sf.saxon.type.AnyFunctionType
          com.saxonica.functions.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.
`int` `hashCode()` Returns a hash code value for the object.
`Expression` `makeFunctionSequenceCoercer(Expression exp, RoleLocator role, TypeCheckerEnvironment 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.
`void` `visitNamedSchemaComponents(SchemaComponentVisitor visitor)` Visit all the schema components used in this ItemType definition

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, 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`

### hashCode

    public int hashCode()

  Returns a hash code value for the object.

  Overrides:
    `hashCode` 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,
                                                  TypeCheckerEnvironment 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`

### visitNamedSchemaComponents

    public void visitNamedSchemaComponents(SchemaComponentVisitor visitor)
                                    throws XPathException

  Visit all the schema components used in this ItemType definition

  Specified by:
    `visitNamedSchemaComponents` in interface `ItemType`
  Overrides:
    `visitNamedSchemaComponents` in class `AnyFunctionType`
  Parameters:
    `visitor` - the visitor class to be called when each component is visited
  Throws:
    `XPathException`

Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.