com.icl.saxon.expr
Class SingletonNodeSet

java.lang.Object
  com.icl.saxon.expr.Expression
      com.icl.saxon.expr.Value
          com.icl.saxon.expr.NodeSetValue
              com.icl.saxon.expr.SingletonNodeSet

All Implemented Interfaces:

org.w3c.dom.NodeList

Direct Known Subclasses:

FragmentValue, TextFragmentValue

public class SingletonNodeSet

extends NodeSetValue

implements org.w3c.dom.NodeList

A node-set value containing zero or one nodes

Field Summary

protected boolean	generalUseAllowed
protected NodeInfo	node

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

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.
java.lang.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
org.w3c.dom.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.

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

asNumber, compare, conversionPreference, convertToJava, display, enumerate, getDataType

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

getDependencies, inverse, numericCompare, reduce, stringToNumber

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

containsReferences, evaluateAsBoolean, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent

Methods inherited from class java.lang.Object

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

Field Detail

node

protected NodeInfo node

generalUseAllowed

protected boolean generalUseAllowed

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

isGeneralUseAllowed

public boolean isGeneralUseAllowed()

Determine if general use as a node-set is allowed

simplify

public Expression simplify()

Simplify the expression

Overrides:

simplify in class Value

Returns:

the simplified expression

evaluate

public Value evaluate(Context context)

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

Overrides:

evaluate in class NodeSetValue

Parameters:

context - The context for evaluation (not used)

evaluateAsNodeSet

public NodeSetValue evaluateAsNodeSet(Context context)

Evaluate an expression as a NodeSet.

Overrides:

evaluateAsNodeSet in class NodeSetValue

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the value of the expression, evaluated in the current context

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.

Specified by:

setSorted in class 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

isSorted

public boolean isSorted()

Test whether the value is known to be sorted

Specified by:

isSorted in class NodeSetValue

Returns:

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

asString

public java.lang.String asString()

Convert to string value

Specified by:

asString in class NodeSetValue

Returns:

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

asBoolean

public boolean asBoolean()

Evaluate as a boolean.

Specified by:

asBoolean in class NodeSetValue

Returns:

true if the node set is not empty

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.

Specified by:

getCount in class NodeSetValue

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)

Specified by:

sort in class NodeSetValue

Returns:

the same NodeSetValue, after sorting. (Historic)

getFirst

public NodeInfo getFirst()

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

Specified by:

getFirst in class NodeSetValue

Returns:

the first node

equals

public boolean equals(Value other)
               throws XPathException

Test whether a nodeset "equals" another Value

Overrides:

equals in class NodeSetValue

Throws:

XPathException

notEquals

public boolean notEquals(Value other)
                  throws XPathException

Test whether a nodeset "not-equals" another Value

Overrides:

notEquals in class NodeSetValue

Throws:

XPathException

enumerate

public NodeEnumeration enumerate()
                          throws XPathException

Return an enumeration of this nodeset value.

Specified by:

enumerate in class NodeSetValue

Throws:

XPathException

getLength

public int getLength()

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

Specified by:

getLength in interface org.w3c.dom.NodeList

item

public org.w3c.dom.Node item(int index)

Return the n'th item in the list (DOM method)

Specified by:

item in interface org.w3c.dom.NodeList