Class NodeTest

java.lang.Object
net.sf.saxon.pattern.NodeTest
All Implemented Interfaces:
Serializable, ItemType
Direct Known Subclasses:
AnyChildNodeTest, AnyNodeTest, CombinedNodeTest, ContentTypeTest, DocumentNodeTest, EmptySequenceTest, LocalNameTest, NamespaceTest, NameTest, NodeKindTest
public abstract class NodeTest extends Object implements ItemType, Serializable
A NodeTest is a simple kind of pattern that enables a context-free test of whether a node matches a given node kind and name. There are several kinds of node test: a full name test, a prefix test, and an "any node of a given type" test, an "any node of any type" test, a "no nodes" test (used, e.g. for "@comment()").

As well as being used to support XSLT pattern matching, NodeTests act as predicates in axis steps, and also act as item types for type matching.

For use in user-written application calling NodeInfo.iterateAxis(byte, NodeTest), it is possible to write a user-defined subclass of NodeTest that implements a single method, matches(int, NodeName, int)

Author:
Michael H. Kay
See Also:

  • Constructor Details

    • NodeTest

      public NodeTest()

  • Method Details

    • matches

      public boolean matches(Item item, XPathContext context)
      Description copied from interface: ItemType
      Test whether a given item conforms to this type
      Specified by:
      matches in interface ItemType
      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

      public boolean matchesItem(Item item, boolean allowURIPromotion, Configuration config)
      Test whether a given item conforms to this type. This implements a method of the ItemType interface.
      Specified by:
      matchesItem in interface ItemType
      Parameters:
      item - The item to be tested
      allowURIPromotion - true of promotion of anyURI to string is permitted
      config - the Saxon Configuration
      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
      Parameters:
      th - the type hierarchy cache
      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.
      Specified by:
      getPrimitiveItemType in interface ItemType
      Returns:
      the corresponding primitive type

    • getPrimitiveType

      public int getPrimitiveType()
      Get the basic kind of object that this ItemType matches: for a NodeTest, this is the kind of node, or Type.Node if it matches different kinds of nodes.
      Specified by:
      getPrimitiveType in interface ItemType
      Returns:
      the node kind matched by this node test

    • getFingerprint

      public int getFingerprint()
      Get the name of the nodes matched by this nodetest, if it matches a specific name. Return -1 if the node test matches nodes of more than one name

    • isAtomicType

      public boolean isAtomicType()
      Determine whether this item type is an atomic type
      Specified by:
      isAtomicType in interface ItemType
      Returns:
      true if this is ANY_ATOMIC_TYPE or a subtype thereof

    • isPlainType

      public boolean isPlainType()
      Determine whether this item type is atomic (that is, whether it can ONLY match atomic values)
      Specified by:
      isPlainType in interface ItemType
      Returns:
      false: this is not ANY_ATOMIC_TYPE or a subtype thereof

    • getAtomizedItemType

      public AtomicType getAtomizedItemType()
      Get the item type of the atomic values that will be produced when an item of this type is atomized (assuming that atomization succeeds)
      Specified by:
      getAtomizedItemType in interface ItemType
      Returns:
      the best available item type of the atomic values that will be produced when an item of this type is atomized

    • isAtomizable

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

    • matches

      public boolean matches(TinyTree tree, int nodeNr)
      Test whether this node test is satisfied by a given node on a TinyTree. The node must be a document, element, text, comment, or processing instruction node. This method is provided so that when navigating a TinyTree a node can be rejected without actually instantiating a NodeInfo object. The default implementation instantiates the node and then calls the method matches(NodeInfo)
      Parameters:
      tree - the TinyTree containing the node
      nodeNr - the number of the node within the TinyTree
      Returns:
      true if the node matches the NodeTest, otherwise false

    • matches

      public abstract boolean matches(int nodeKind, NodeName name, int annotation)
      Test whether this node test is satisfied by a given node. This method is only fully supported for a subset of NodeTests, because it doesn't provide all the information needed to evaluate all node tests. In particular (a) it can't be used to evaluate a node test of the form element(N,T) or schema-element(E) where it is necessary to know whether the node is nilled, and (b) it can't be used to evaluate a node test of the form document-node(element(X)). This in practice means that it is used (a) to evaluate the simple node tests found in the XPath 1.0 subset used in XML Schema, and (b) to evaluate node tests where the node kind is known to be an attribute.
      Parameters:
      nodeKind - The kind of node to be matched
      name - identifies the expanded name of the node to be matched. The value should be null for a node with no name.
      annotation - The actual content type of the node

    • matches

      public boolean matches(NodeInfo node)
      Test whether this node test is satisfied by a given node. This alternative method is used in the case of nodes where calculating the fingerprint is expensive, for example DOM or JDOM nodes. The default implementation calls the method matches(int, NodeName, int)
      Parameters:
      node - the node to be matched

    • getNodeKindMask

      public int getNodeKindMask()
      Get a mask indicating which kinds of nodes this NodeTest can match. This is a combination of bits: 1invalid input: '<'invalid input: '<'Type.ELEMENT for element nodes, 1invalid input: '<'invalid input: '<'Type.TEXT for text nodes, and so on. The default implementation indicates that nodes of all kinds are matched.
      Returns:
      a combination of bits: 1invalid input: '<'invalid input: '<'Type.ELEMENT for element nodes, 1invalid input: '<'invalid input: '<'Type.TEXT for text nodes, and so on

    • getContentType

      public SchemaType getContentType()
      Get the content type allowed by this NodeTest (that is, the type annotation of the matched nodes). Return AnyType if there are no restrictions. The default implementation returns AnyType.
      Returns:
      the type annotation that all nodes matching this NodeTest must satisfy

    • getRequiredNodeNames

      public IntSet getRequiredNodeNames()
      Get the set of node names allowed by this NodeTest. This is returned as a set of Integer fingerprints. If all names are permitted (i.e. there are no constraints on the node name), returns IntInfiniteSet.getInstance(). The default implementation returns the universal set.
      Returns:
      the set of integer fingerprints of the node names that this node test can match.

    • isNillable

      public boolean isNillable()
      Determine whether the content type (if present) is nillable
      Returns:
      true if the content test (when present) can match nodes that are nilled

    • visitNamedSchemaComponents

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

    • toString

      public String toString(NamePool pool)
      Display the type descriptor for diagnostics
      Specified by:
      toString in interface ItemType
      Parameters:
      pool - the name pool
      Returns:
      a string representation of the type, in notation resembling but not necessarily identical to XPath syntax