net.sf.saxon.pattern

Class CombinedNodeTest

java.lang.Object

net.sf.saxon.pattern.NodeTest

net.sf.saxon.pattern.CombinedNodeTest

All Implemented Interfaces:

ItemType

public class CombinedNodeTest
extends NodeTest

A CombinedNodeTest combines two nodetests using one of the operators union (=or), intersect (=and), difference (= "and not"). This arises when optimizing a union (etc) of two path expressions using the same axis. A CombinedNodeTest is also used to support constructs such as element(N,T), which can be expressed as (element(N,*) AND element(*,T))

Author:

Michael H. Kay

Constructor Summary

Constructors

Constructor and Description
CombinedNodeTest(NodeTest nt1, int operator, NodeTest nt2) Create a NodeTest that combines two other node tests

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object other) Indicates whether some other object is "equal to" this one.
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)
NodeTest[]	getComponentNodeTests() Get the two parts of the combined node test
SchemaType	getContentType() Get the content type allowed by this NodeTest (that is, the type annotation of the matched nodes).
double	getDefaultPriority() Get the default priority of this nodeTest when used 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.
int	getOperator() Get the operator used to combine the two node tests: one of Token.UNION, Token.INTERSECT, Token.EXCEPT,
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.
IntSet	getRequiredNodeNames() Get the set of node names allowed by this NodeTest.
ItemType	getSuperType(TypeHierarchy th) Get the supertype of this type.
int	hashCode() Returns a hash code value for the object.
boolean	isAtomizable() Ask whether values of this type are atomizable
boolean	isNillable() Determine whether the content type (if present) is nillable
boolean	matches(int nodeKind, NodeName name, 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.
String	toString()
void	visitNamedSchemaComponents(SchemaComponentVisitor visitor) Visit all the schema components used in this ItemType definition

Methods inherited from class net.sf.saxon.pattern.NodeTest

getPrimitiveItemType, isAtomicType, isPlainType, matches, matchesItem

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CombinedNodeTest

public CombinedNodeTest(NodeTest nt1,
                int operator,
                NodeTest nt2)

Create a NodeTest that combines two other node tests

Parameters:

nt1 - the first operand. Note that if the defaultPriority of the pattern is required, it will be taken from that of the first operand.

operator - one of Token.UNION, Token.INTERSECT, Token.EXCEPT

nt2 - the second operand

Method Detail

matches

public 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.

Specified by:

matches in class NodeTest

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

Returns:

true if the node matches this node tst

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.

Overrides:

matches in class NodeTest

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 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.

Overrides:

matches in class NodeTest

Parameters:

node - the node to be matched

Returns:

true if the node test is satisfied by the supplied node, false otherwise

toString

public String toString()

Overrides:

toString in class Object

getSuperType

public ItemType getSuperType(TypeHierarchy th)

Get the supertype of this type. This isn't actually a well-defined concept: the types form a lattice rather than a strict hierarchy.

Specified by:

getSuperType in interface ItemType

Overrides:

getSuperType in class NodeTest

Parameters:

th - the type hierarchy cache

Returns:

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

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.

Overrides:

getNodeKindMask in class NodeTest

Returns:

a combination of bits: 1<

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

Overrides:

getPrimitiveType in class NodeTest

Returns:

the node kind matched by this node test

getRequiredNodeNames

public IntSet 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.

Overrides:

getRequiredNodeNames in class NodeTest

Returns:

the set of integer fingerprints of the node names that this node test can match.

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.

Overrides:

getContentType in class NodeTest

Returns:

the type annotation that all nodes matching this NodeTest must satisfy

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

Overrides:

getAtomizedItemType in class NodeTest

Returns:

the best available item type of the atomic values that will be produced when an item of this type is atomized, or null if it is known that atomization will throw an error.

isAtomizable

public boolean isAtomizable()

Ask whether values of this type are atomizable

Specified by:

isAtomizable in interface ItemType

Overrides:

isAtomizable in class NodeTest

Returns:

true unless it is known that these items will be elements with element-only content, in which case return false

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

Overrides:

getFingerprint in class NodeTest

isNillable

public boolean isNillable()

Determine whether the content type (if present) is nillable

Overrides:

isNillable in class NodeTest

Returns:

true if the content test (when present) can match nodes that are nilled

hashCode

public int hashCode()

Returns a hash code value for the object.

Overrides:

hashCode in class Object

equals

public boolean equals(Object other)

Indicates whether some other object is "equal to" this one.

Overrides:

equals in class Object

getDefaultPriority

public double getDefaultPriority()

Get the default priority of this nodeTest when used as a pattern. In the case of a union, this will always be (arbitrarily) the default priority of the first operand. In other cases, again somewhat arbitrarily, it is 0.25, reflecting the common usage of an intersection to represent the pattern element(E, T).

Specified by:

getDefaultPriority in class NodeTest

Returns:

the default priority for the pattern

getComponentNodeTests

public NodeTest[] getComponentNodeTests()

Get the two parts of the combined node test

Returns:

the two operands

getOperator

public int getOperator()

Get the operator used to combine the two node tests: one of Token.UNION, Token.INTERSECT, Token.EXCEPT,

Returns:

the operator

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 NodeTest

Parameters:

visitor - the visitor class to be called when each component is visited

Throws:

XPathException - if an error occurs