net.sf.saxon.pattern
Class EmptySequenceTest

java.lang.Object
  extended by net.sf.saxon.pattern.NodeTest
      extended by 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
 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, toString
 
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

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

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


Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.