com.icl.saxon.expr
Class SortKeyEnumeration

java.lang.Object
  com.icl.saxon.expr.SortKeyEnumeration

All Implemented Interfaces:

LastPositionFinder, NodeEnumeration, Sortable

public final class SortKeyEnumeration

extends java.lang.Object

implements NodeEnumeration, LastPositionFinder, Sortable

A SortKeyEnumeration is NodeEnumeration that delivers the nodes sorted according to a specified sort key.

Field Summary

protected NodeEnumeration

base

Constructor Summary

SortKeyEnumeration(Context context, NodeEnumeration _base, SortKeyDefinition[] sortkeys)

Method Summary

int	compare(int a, int b) Compare two nodes in sorted sequence (needed to implement the Sortable interface)
int	getLastPosition() Get the last position
boolean	hasMoreElements() Determine whether there are more nodes
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 sorted order
void	swap(int a, int b) Swap two nodes (needed to implement the Sortable interface)

Methods inherited from class java.lang.Object

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

Field Detail

base

protected NodeEnumeration base

Constructor Detail

SortKeyEnumeration

public SortKeyEnumeration(Context context,
                          NodeEnumeration _base,
                          SortKeyDefinition[] sortkeys)
                   throws XPathException

Method Detail

hasMoreElements

public boolean hasMoreElements()

Determine whether there are more nodes

Specified by:

hasMoreElements in interface NodeEnumeration

Returns:

true if there are more nodes

nextElement

public NodeInfo nextElement()
                     throws XPathException

Get the next node, in sorted order

Specified by:

nextElement in interface NodeEnumeration

Returns:

the next NodeInfo

Throws:

XPathException

isSorted

public boolean isSorted()

Description copied from interface: NodeEnumeration

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.

isReverseSorted

public boolean isReverseSorted()

Description copied from interface: NodeEnumeration

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.

isPeer

public boolean isPeer()

Description copied from interface: NodeEnumeration

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

getLastPosition

public int getLastPosition()
                    throws XPathException

Description copied from interface: LastPositionFinder

Get the last position

Specified by:

getLastPosition in interface LastPositionFinder

Throws:

XPathException

compare

public int compare(int a,
                   int b)

Compare two nodes in sorted sequence (needed to implement the Sortable interface)

Specified by:

compare in interface Sortable

Returns:

<0 if obj[a]0 if obj[a]>obj[b]

swap

public void swap(int a,
                 int b)

Swap two nodes (needed to implement the Sortable interface)

Specified by:

swap in interface Sortable