net.sf.saxon.pattern

Class EmptySequenceTest

java.lang.Object

net.sf.saxon.pattern.NodeTest

net.sf.saxon.pattern.EmptySequenceTest

All Implemented Interfaces:

Serializable, ItemType

public final class EmptySequenceTest
extends NodeTest

NodeTest is an interface that enables a test of whether a node has a particular name and type. An EmptySequenceTest matches no nodes or atomic values: it corresponds to the type empty-sequence().

Author:

Michael H. Kay

See Also:

Serialized Form

Method Summary

Methods

Modifier and Type	Method and Description
double	getDefaultPriority() Determine the default priority of this node test when used on its own as a Pattern
static EmptySequenceTest	getInstance() Get a NoNodeTest instance
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.
int	hashCode() Returns a hash code value for the object.
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.
boolean	matchesItem(Item item, boolean allowURIPromotion, Configuration config) Test whether a given item conforms to this type
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

getAtomizedItemType, getContentType, getFingerprint, getRequiredNodeNames, getSuperType, isAtomicType, isAtomizable, isNillable, isPlainType, matches

Methods inherited from class java.lang.Object

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

Method Detail

getInstance

public static EmptySequenceTest getInstance()

Get a NoNodeTest instance

getPrimitiveType

public final int getPrimitiveType()

Description copied from class: NodeTest

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

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

Overrides:

getPrimitiveItemType in class NodeTest

Returns:

the corresponding primitive type

matchesItem

public boolean matchesItem(Item item,
                  boolean allowURIPromotion,
                  Configuration config)

Test whether a given item conforms to this type

Specified by:

matchesItem in interface ItemType

Overrides:

matchesItem in class NodeTest

Parameters:

item - The item to be tested

allowURIPromotion -

config -

Returns:

true if the item is an instance of this type; false otherwise

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

getDefaultPriority

public final double getDefaultPriority()

Determine the default priority of this node test when used on its own as a Pattern

Returns:

the default priority

getNodeKindMask

public int getNodeKindMask()

Get a mask indicating which kinds of nodes this NodeTest can match. This is a combination of bits: 1<

Overrides:

getNodeKindMask in class NodeTest

Returns:

a combination of bits: 1<

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

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Returns a hash code value for the object.

Overrides:

hashCode in class Object