net.sf.saxon.pattern
Class NodeTest
java.lang.Object
net.sf.saxon.pattern.NodeTest
- ItemType, Serializable
public abstract class NodeTest
extends java.lang.Object
A NodeTest is a simple kind of pattern that enables a context-free test of whether
a node has a particular
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,int,int)
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)
|
SchemaType | getContentType() - Get the content type allowed by this NodeTest (that is, the type annotation of the matched nodes).
|
abstract double | getDefaultPriority() - Determine the default priority of this node test when used on its own as a Pattern
|
int | getFingerprint() - Get the name of the nodes matched by this nodetest, if it matches a specific name.
|
int | getNodeKindMask() - Get a mask indicating which kinds of nodes this NodeTest can match.
|
ItemType | getPrimitiveItemType() - Get the primitive item type corresponding to this item type.
|
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.
|
IntHashSet | getRequiredNodeNames() - Get the set of node names allowed by this NodeTest.
|
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 | isNillable() - Determine whether the content type (if present) is nillable
|
abstract boolean | matches(int nodeKind, int fingerprint, int annotation) - Test whether this node test is satisfied by a given node.
|
boolean | matches(NodeInfo node) - Test whether this node test is satisfied by a given node.
|
boolean | matches(TinyTree tree, int nodeNr) - Test whether this node test is satisfied by a given node on a TinyTree.
|
boolean | matchesItem(Item item, boolean allowURIPromotion, Configuration config) - Test whether a given item conforms to this type.
|
String | toString(NamePool pool) - Display the type descriptor for diagnostics
|
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)
- getAtomizedItemType in interface ItemType
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.
getDefaultPriority
public abstract double getDefaultPriority()
Determine the default priority of this node test when used on its own as a Pattern
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
getNodeKindMask
public int getNodeKindMask()
Get a mask indicating which kinds of nodes this NodeTest can match. This is a combination
of bits: 1<<Type.ELEMENT for element nodes, 1<<Type.TEXT for text nodes, and so on. The default
implementation indicates that nodes of all kinds are matched.
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.
- getPrimitiveItemType in interface ItemType
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.
- getPrimitiveType in interface ItemType
- the node kind matched by this node test
getRequiredNodeNames
public IntHashSet getRequiredNodeNames()
Get the set of node names allowed by this NodeTest. This is returned as a set of Integer fingerprints.
A null value indicates that all names are permitted (i.e. that there are no constraints on the node name.
The default implementation returns null.
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.
- getSuperType in interface ItemType
th
- the type hierarchy cache
- the supertype, or null if this type is item()
isAtomicType
public boolean isAtomicType()
Determine whether this item type is atomic (that is, whether it can ONLY match
atomic values)
- isAtomicType in interface ItemType
- false: this is not ANY_ATOMIC_TYPE or a subtype thereof
isNillable
public boolean isNillable()
Determine whether the content type (if present) is nillable
- true if the content test (when present) can match nodes that are nilled
matches
public abstract boolean matches(int nodeKind,
int fingerprint,
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.
nodeKind
- The kind of node to be matchedfingerprint
- identifies the expanded name of the node to be matched.
The value should be -1 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,int,int)
node
- the node to be matched
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)
tree
- the TinyTree containing the nodenodeNr
- the number of the node within the TinyTree
- true if the node matches the NodeTest, otherwise false
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.
- matchesItem in interface ItemType
item
- The item to be testedallowURIPromotion
- config
-
- true if the item is an instance of this type; false otherwise
toString
public String toString(NamePool pool)
Display the type descriptor for diagnostics
- toString in interface ItemType