com.icl.saxon.expr

Class SingletonNodeSet

public class SingletonNodeSet extends NodeSetValue implements NodeList

A node-set value containing zero or one nodes

Field Summary
protected boolean	generalUseAllowed
protected NodeInfo	node

Constructor Summary
	SingletonNodeSet() Create an empty node-set
	SingletonNodeSet(NodeInfo node) Create a node-set containing one node

Method Summary
void	allowGeneralUse() Allow general use as a node-set.
boolean	asBoolean() Evaluate as a boolean.
String	asString() Convert to string value
NodeEnumeration	enumerate() Return an enumeration of this nodeset value.
boolean	equals(Value other) Test whether a nodeset "equals" another Value
Value	evaluate(Context context) Evaluate the Node Set.
NodeSetValue	evaluateAsNodeSet(Context context) Evaluate an expression as a NodeSet.
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	isGeneralUseAllowed() Determine if general use as a node-set is allowed
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)
boolean	notEquals(Value other) Test whether a nodeset "not-equals" another Value
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.

Field Detail

generalUseAllowed

protected boolean generalUseAllowed

node

protected NodeInfo node

Constructor Detail

SingletonNodeSet

public SingletonNodeSet()

Create an empty node-set

SingletonNodeSet

public SingletonNodeSet(NodeInfo node)

Create a node-set containing one node

Method Detail

allowGeneralUse

public void allowGeneralUse()

Allow general use as a node-set. This is required to lift the 1.0 restrictions on use of result tree fragments

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

enumerate

public NodeEnumeration enumerate()

Return an enumeration of this nodeset value.

equals

public boolean equals(Value other)

Test whether a nodeset "equals" another Value

evaluate

public Value evaluate(Context context)

Evaluate the Node Set. This guarantees to return the result in sorted order.

Parameters: context The context for evaluation (not used)

evaluateAsNodeSet

public NodeSetValue evaluateAsNodeSet(Context context)

Evaluate an expression as a NodeSet.

Parameters: context The context in which the expression is to be evaluated

Returns: the value of the expression, evaluated in the current context

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

getLength

public int getLength()

return the number of nodes in the list (DOM method)

isGeneralUseAllowed

public boolean isGeneralUseAllowed()

Determine if general use as a node-set is allowed

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)

notEquals

public boolean notEquals(Value other)

Test whether a nodeset "not-equals" another Value

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. (Historic)