com.icl.saxon.expr

Class DifferenceEnumeration

Implemented Interfaces:
NodeEnumeration

public class DifferenceEnumeration
extends java.lang.Object
implements NodeEnumeration

An enumeration representing a nodeset that is an intersection of two other NodeSets. There is currently no operator in XPath to create such an expression, but it is used by the extension function difference(). The code is derived from the analagous UnionEnumeration, an inner class of UnionExpression.

Field Summary

(package private) NodeInfo
nextNode

Constructor Summary

DifferenceEnumeration(NodeEnumeration p1, NodeEnumeration p2, Controller controller)
Form an enumeration of the difference of two nodesets, that is, the nodes that are in p1 and that are not in p2.

Method Summary

boolean
hasMoreElements()
Determine whether there are more nodes to come.
boolean
isPeer()
Determine whether the nodes returned by this enumeration are known to be peers, that is, no node is a descendant or ancestor of another node.
boolean
isReverseSorted()
Determine whether the nodes returned by this enumeration are known to be in reverse document order.
boolean
isSorted()
Determine whether the nodes returned by this enumeration are known to be in document order
NodeInfo
nextElement()
Get the next node in sequence.

Field Details

nextNode

(package private)  NodeInfo nextNode

Constructor Details

DifferenceEnumeration

public DifferenceEnumeration(NodeEnumeration p1,
                             NodeEnumeration p2,
                             Controller controller)
            throws XPathException
Form an enumeration of the difference of two nodesets, that is, the nodes that are in p1 and that are not in p2.
Parameters:
p1 - the first operand
p2 - the second operand

Method Details

hasMoreElements

public boolean hasMoreElements()
Determine whether there are more nodes to come.
(Note the term "Element" is used here in the sense of the standard Java Enumeration class, it has nothing to do with XML elements).
Specified by:
hasMoreElements in interface NodeEnumeration
Returns:
true if there are more nodes

isPeer

public boolean isPeer()
Determine whether the nodes returned by this enumeration are known to be peers, that is, no node is a descendant or ancestor of another node. This significance of this property is that if a peer enumeration is applied to each node in a set derived from another peer enumeration, and if both enumerations are sorted, then the result is also sorted.
Specified by:
isPeer in interface NodeEnumeration

isReverseSorted

public boolean isReverseSorted()
Determine whether the nodes returned by this enumeration are known to be in reverse document order.
Specified by:
isReverseSorted in interface NodeEnumeration
Returns:
true if the nodes are guaranteed to be in document order.

isSorted

public boolean isSorted()
Determine whether the nodes returned by this enumeration are known to be in document order
Specified by:
isSorted in interface NodeEnumeration
Returns:
true if the nodes are guaranteed to be in document order.

nextElement

public NodeInfo nextElement()
            throws XPathException
Get the next node in sequence.
(Note the term "Element" is used here in the sense of the standard Java Enumeration class, it has nothing to do with XML elements).
Specified by:
nextElement in interface NodeEnumeration
Returns:
the next NodeInfo