com.icl.saxon.expr

Class NodeSetExtent

public final class NodeSetExtent extends NodeSetValue implements Sortable, 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).

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

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)

Constructor Detail

NodeSetExtent

public NodeSetExtent(NodeOrderComparer comparer)

Construct an empty node set

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(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 enm, NodeOrderComparer comparer)

Construct a node-set containing all the nodes in a NodeEnumeration.

Parameters: enm 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

Method Detail

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()

Evaluate as a boolean.

Returns: true if the node set is not empty

asString

public String asString()

Convert to string value

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)

enumerate

public NodeEnumeration enumerate()

Return an enumeration of this nodeset value.

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.

getFirst

public NodeInfo getFirst()

Get the first node in the nodeset (in document order)

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

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.

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

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)

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)