com.icl.saxon.expr

Class NodeSetExtent

Implemented Interfaces:
org.w3c.dom.NodeList, Sortable

public final class NodeSetExtent
extends NodeSetValue
implements Sortable, org.w3c.dom.NodeList

A node-set value implemented extensionally. This class also implements the DOM NodeList interface - though this will only work if the nodes themselves implement the DOM Node interface (which is true of the two Saxon tree models, but not necessarily of all possible implementations).

Nested Class Summary

Field Summary

Fields inherited from class com.icl.saxon.expr.Value

ANY, BOOLEAN, NODESET, NUMBER, OBJECT, STRING

Fields inherited from class com.icl.saxon.expr.Expression

staticContext

Constructor Summary

NodeSetExtent(Vector nodes, NodeOrderComparer comparer)
Construct a node-set given the set of nodes as a Vector
NodeSetExtent(NodeEnumeration enum, NodeOrderComparer comparer)
Construct a node-set containing all the nodes in a NodeEnumeration.
NodeSetExtent(NodeInfo nodes, NodeOrderComparer comparer)
Construct a node-set given the set of nodes as an array
NodeSetExtent(NodeOrderComparer comparer)
Construct an empty node set

Method Summary

void
append(NodeInfo node)
Append a node to the node-set.
boolean
asBoolean()
Evaluate as a boolean.
String
asString()
Convert to string value
int
compare(int a, int b)
Compare two nodes in document sequence (needed to implement the Sortable interface)
NodeEnumeration
enumerate()
Return an enumeration of this nodeset value.
int
getCount()
Count the nodes in the node-set.
NodeInfo
getFirst()
Get the first node in the nodeset (in document order)
int
getLength()
return the number of nodes in the list (DOM method)
boolean
isSorted()
Test whether the value is known to be sorted
Node
item(int index)
Return the n'th item in the list (DOM method)
NodeInfo
selectFirst(Context context)
Return the first node in the nodeset (in document order)
void
setSorted(boolean isSorted)
Set a flag to indicate whether the nodes are sorted.
Expression
simplify()
Simplify the expression
NodeSetValue
sort()
Sort the nodes into document order.
void
swap(int a, int b)
Swap two nodes (needed to implement the Sortable interface)

Methods inherited from class com.icl.saxon.expr.NodeSetValue

asBoolean, asNumber, asString, compare, conversionPreference, convertToJava, display, enumerate, enumerate, equals, evaluate, evaluateAsNodeSet, getCount, getDataType, getFirst, isSorted, notEquals, setSorted, sort

Methods inherited from class com.icl.saxon.expr.Value

asBoolean, asNumber, asString, compare, conversionPreference, convertToJava, equals, evaluate, getDependencies, inverse, notEquals, numericCompare, reduce, simplify, stringToNumber

Methods inherited from class com.icl.saxon.expr.Expression

containsReferences, display, enumerate, evaluate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getDataType, getDependencies, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, reduce, setStaticContext, simplify, usesCurrent

Constructor Details

NodeSetExtent

public NodeSetExtent(Vector nodes,
                     NodeOrderComparer comparer)
Construct a node-set given the set of nodes as a Vector

Parameters:
nodes - a Vector whose elements must be NodeInfo objects
comparer - Comparer used for sorting into document order


NodeSetExtent

public NodeSetExtent(NodeEnumeration enum,
                     NodeOrderComparer comparer)
            throws XPathException
Construct a node-set containing all the nodes in a NodeEnumeration.

Parameters:
enum - The supplied node enumeration. This must be positioned at the start, so that hasMoreElements() returns true if there are any nodes in the node-set, and nextElement() returns the first node.
comparer - Comparer used for sorting into document order


NodeSetExtent

public NodeSetExtent(NodeInfo nodes,
                     NodeOrderComparer comparer)
Construct a node-set given the set of nodes as an array

Parameters:
nodes - An array whose elements must be NodeInfo objects
comparer - Comparer used for sorting into document order


NodeSetExtent

public NodeSetExtent(NodeOrderComparer comparer)
Construct an empty node set

Method Details

append

public void append(NodeInfo node)
Append a node to the node-set. This is used only when building indexes. The node-set must be sorted; the new node must follow the others in document order. The new node is not added if it is the same as the last node currently in the node-set.


asBoolean

public boolean asBoolean()
            throws XPathException
Evaluate as a boolean.
Overrides:
asBoolean in interface NodeSetValue

Returns:
true if the node set is not empty


asString

public String asString()
Convert to string value
Overrides:
asString in interface NodeSetValue

Returns:
the value of the first node in the node-set if there is one, otherwise an empty string


compare

public int compare(int a,
                   int b)
Compare two nodes in document sequence (needed to implement the Sortable interface)
Specified by:
compare in interface Sortable


enumerate

public NodeEnumeration enumerate()
Return an enumeration of this nodeset value.
Overrides:
enumerate in interface NodeSetValue


getCount

public int getCount()
Count the nodes in the node-set. Note this will sort the node set if necessary, to make sure there are no duplicates.
Overrides:
getCount in interface NodeSetValue


getFirst

public NodeInfo getFirst()
Get the first node in the nodeset (in document order)
Overrides:
getFirst in interface NodeSetValue

Returns:
the first node, or null if the nodeset is empty


getLength

public int getLength()
return the number of nodes in the list (DOM method)


isSorted

public boolean isSorted()
Test whether the value is known to be sorted
Overrides:
isSorted in interface NodeSetValue

Returns:
true if the value is known to be sorted in document order, false if it is not known whether it is sorted.


item

public Node item(int index)
Return the n'th item in the list (DOM method)


selectFirst

public NodeInfo selectFirst(Context context)
Return the first node in the nodeset (in document order)

Parameters:
context - The context for the evaluation: not used

Returns:
the NodeInfo of the first node in document order, or null if the node-set is empty.


setSorted

public void setSorted(boolean isSorted)
Set a flag to indicate whether the nodes are sorted. Used when the creator of the node-set knows that they are already in document order.
Overrides:
setSorted in interface NodeSetValue

Parameters:
isSorted - true if the caller wishes to assert that the nodes are in document order and do not need to be further sorted


simplify

public Expression simplify()
Simplify the expression
Overrides:
simplify in interface Value


sort

public NodeSetValue sort()
Sort the nodes into document order. This does nothing if the nodes are already known to be sorted; to force a sort, call setSorted(false)
Overrides:
sort in interface NodeSetValue

Returns:
the same NodeSetValue, after sorting. (The reason for returning this is that it makes life easier for the XSL compiler).


swap

public void swap(int a,
                 int b)
Swap two nodes (needed to implement the Sortable interface)
Specified by:
swap in interface Sortable