net.sf.saxon.type
Interface ItemType

All Superinterfaces:

java.io.Serializable

All Known Subinterfaces:

AtomicType

All Known Implementing Classes:

AnyItemType, BuiltInAtomicType, ExternalObjectType, NodeTest, UserAtomicType

public interface ItemType

extends java.io.Serializable

ItemType is an interface that allows testing of whether an Item conforms to an expected type. ItemType represents the types in the type hierarchy in the XPath model, as distinct from the schema model: an item type is either item() (matches everything), a node type (matches nodes), an atomic type (matches atomic values), or empty() (matches nothing). Atomic types, represented by the class AtomicType, are also instances of SimpleType in the schema type heirarchy. Node Types, represented by the class NodeTest, are also Patterns as used in XSLT.

See Also:

AtomicType, NodeTest

Method Summary

AtomicType	getAtomizedItemType() Get the item type of the atomic values that will be produced when an item of this type is atomized
ItemType	getPrimitiveItemType() Get the primitive item type corresponding to this item type.
int	getPrimitiveType() Get the primitive type corresponding to this item type.
ItemType	getSuperType(TypeHierarchy th) Get the type from which this item type is derived by restriction.
boolean	isAtomicType() Determine whether this item type is atomic (that is, whether it can ONLY match atomic values)
boolean	matchesItem(Item item, XPathContext context, boolean allowURIPromotion) Test whether a given item conforms to this type
java.lang.String	toString(NamePool pool) Produce a representation of this type name for use in error messages.

Method Detail

isAtomicType

public boolean isAtomicType()

Determine whether this item type is atomic (that is, whether it can ONLY match atomic values)

Returns:

true if this is ANY_ATOMIC_TYPE or a subtype thereof

matchesItem

public boolean matchesItem(Item item,
                           XPathContext context,
                           boolean allowURIPromotion)

Test whether a given item conforms to this type

Parameters:

item - The item to be tested

context -

allowURIPromotion -

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 xdt: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.

Parameters:

th -

Returns:

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

getPrimitiveItemType

public ItemType getPrimitiveItemType()

Get the primitive item type corresponding to this item type. For item(), this is Type.ITEM. For node(), it is Type.NODE. For specific node kinds, it is the value representing the node kind, for example Type.ELEMENT. For anyAtomicValue it is Type.ATOMIC_VALUE. For numeric it is Type.NUMBER. For other atomic types it is the primitive type as defined in XML Schema, except that INTEGER is considered to be a primitive type.

getPrimitiveType

public int getPrimitiveType()

Get the primitive type corresponding to this item type. For item(), this is Type.ITEM. For node(), it is Type.NODE. For specific node kinds, it is the value representing the node kind, for example Type.ELEMENT. For anyAtomicValue it is Type.ATOMIC_VALUE. For numeric it is Type.NUMBER. For other atomic types it is the primitive type as defined in XML Schema, except that INTEGER is considered to be a primitive type.

toString

public java.lang.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

getAtomizedItemType

public AtomicType getAtomizedItemType()

Get the item type of the atomic values that will be produced when an item of this type is atomized