Interface ItemType

All Superinterfaces:
Serializable
All Known Subinterfaces:
AtomicType, FunctionItemType, PlainType
All Known Implementing Classes:
AnyChildNodeTest, AnyFunctionType, AnyItemType, AnyNodeTest, BuiltInAtomicType, CombinedNodeTest, ContentTypeTest, DocumentNodeTest, EmptySequenceTest, ExternalObjectType, LocalNameTest, NamespaceTest, NameTest, NodeKindTest, NodeTest

public interface ItemType extends 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 hierarchy. Node Types, represented by the class NodeTest, are also Patterns as used in XSLT.

Saxon assumes that apart from AnyItemType (which corresponds to item() and matches anything), every ItemType will be either an AtomicType, a NodeTest, or a FunctionItemType. User-defined implementations of ItemType must therefore extend one of those three classes/interfaces.

See Also:
  • Method Details

    • isAtomicType

      boolean isAtomicType()
      Determine whether this item type is an atomic type
      Returns:
      true if this is ANY_ATOMIC_TYPE or a subtype thereof
    • isPlainType

      boolean isPlainType()
      Determine whether this item type is a plain type (that is, whether it can ONLY match atomic values)
      Returns:
      true if this is ANY_ATOMIC_TYPE or a subtype thereof, or a "plain" union type (that is, unions of atomic types that impose no further restrictions)
    • matches

      boolean matches(Item item, XPathContext context)
      Test whether a given item conforms to this type
      Parameters:
      item - The item to be tested
      context - the XPath dynamic evaluation context
      Returns:
      true if the item is an instance of this type; false otherwise
    • matchesItem

      boolean matchesItem(Item item, boolean allowURIPromotion, Configuration config)
      Test whether a given item conforms to this type
      Parameters:
      item - The item to be tested
      allowURIPromotion - if a URI value is to be treated as a string
      config - the Saxon configuration
      Returns:
      true if the item is an instance of this type; false otherwise
    • getSuperType

      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.

      Parameters:
      th - the type hierarchy cache
      Returns:
      the supertype, or null if this type is item()
    • getPrimitiveItemType

      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 and union types 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, xs:dayTimeDuration, and xs:yearMonthDuration are considered to be primitive types.
      Returns:
      the corresponding primitive type
    • getPrimitiveType

      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 BuiltInAtomicType.ANY_ATOMIC. 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.
      Returns:
      the integer fingerprint of the corresponding primitive type
    • getDefaultPriority

      double getDefaultPriority()
      Determine the default priority of this item type when used on its own as a Pattern
      Returns:
      the default priority
    • toString

      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
      Parameters:
      pool - the name pool
      Returns:
      a string representation of the type, in notation resembling but not necessarily identical to XPath syntax
    • getAtomizedItemType

      PlainType getAtomizedItemType()
      Get the item type of the atomic values that will be produced when an item of this type is atomized
      Returns:
      the best available item type of the atomic values that will be produced when an item of this type is atomized
    • isAtomizable

      boolean isAtomizable()
      Ask whether values of this type are atomizable
      Returns:
      true unless it is known that these items will be elements with element-only content, or function items, in which case return false
    • visitNamedSchemaComponents

      void visitNamedSchemaComponents(SchemaComponentVisitor visitor) throws XPathException
      Visit all the schema components used in this ItemType definition
      Parameters:
      visitor - the visitor class to be called when each component is visited
      Throws:
      XPathException - if an error occurs