Package net.sf.saxon.value
Class SingletonNode
- java.lang.Object
-
- net.sf.saxon.value.Value
-
- net.sf.saxon.value.SingletonNode
-
- All Implemented Interfaces:
java.io.Serializable
,SequenceIterable
,GroundedValue
,ValueRepresentation
public class SingletonNode extends Value implements GroundedValue
A value that is a sequence containing zero or one nodes- See Also:
- Serialized Form
-
-
Field Summary
Fields Modifier and Type Field Description protected NodeInfo
node
-
Fields inherited from class net.sf.saxon.value.Value
EMPTY_CLASS_ARRAY, INDETERMINATE_ORDERING
-
Fields inherited from interface net.sf.saxon.om.ValueRepresentation
EMPTY_VALUE_ARRAY
-
-
Constructor Summary
Constructors Constructor Description SingletonNode(NodeInfo node)
Create a node-set containing zero or one nodes
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Item
asItem()
Return the value in the form of an Itemboolean
effectiveBooleanValue()
Get the effective boolean valueint
getCardinality()
Determine the static cardinalityItemType
getItemType(TypeHierarchy th)
Determine the data type of the items in the expression.int
getLength()
Get the length of the sequenceNodeInfo
getNode()
Get the node that forms the node-set.java.lang.String
getStringValue()
Convert the value to a string, using the serialization rules.Item
itemAt(int n)
Get the n'th item in the sequence (starting from 0).SequenceIterator
iterate()
Return an enumeration of this nodeset value.void
process(XPathContext context)
Process the instruction, without returning any tail callsGroundedValue
subsequence(int start, int length)
Get a subsequence of the value-
Methods inherited from class net.sf.saxon.value.Value
asItem, asIterator, asValue, checkPermittedContents, convertToJava, equals, fromItem, getCanonicalLexicalRepresentation, getIterator, getSchemaComparable, getStringValueCS, iterate, makeQNameValue, reduce, stringToNumber, toString
-
Methods inherited from class java.lang.Object
clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
-
Methods inherited from interface net.sf.saxon.om.ValueRepresentation
getStringValueCS
-
-
-
-
Field Detail
-
node
protected NodeInfo node
-
-
Constructor Detail
-
SingletonNode
public SingletonNode(NodeInfo node)
Create a node-set containing zero or one nodes- Parameters:
node
- The node to be contained in the node-set, or null if the node-set is to be empty
-
-
Method Detail
-
asItem
public Item asItem()
Return the value in the form of an Item
-
process
public void process(XPathContext context) throws XPathException
Process the instruction, without returning any tail calls- Overrides:
process
in classValue
- Parameters:
context
- The dynamic context, giving access to the current node, the current variables, etc.- Throws:
XPathException
-
getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the items in the expression. This method determines the most precise type that it can, because it is called when testing that the node conforms to a required type.- Overrides:
getItemType
in classValue
- Parameters:
th
- the type hierarchy cache- Returns:
- the most precise possible type of the node.
-
getCardinality
public int getCardinality()
Determine the static cardinality- Overrides:
getCardinality
in classValue
- Returns:
- the cardinality
-
getLength
public int getLength() throws XPathException
Get the length of the sequence- Overrides:
getLength
in classValue
- Returns:
- the number of items in the sequence
- Throws:
XPathException
-
itemAt
public Item itemAt(int n)
Get the n'th item in the sequence (starting from 0). This is defined for all SequenceValues, but its real benefits come for a SequenceValue stored extensionally (or for a MemoClosure, once all the values have been read)- Specified by:
itemAt
in interfaceGroundedValue
- Overrides:
itemAt
in classValue
- Parameters:
n
- position of the required item, counting from zero.- Returns:
- the n'th item in the sequence, where the first item in the sequence is numbered zero. If n is negative or >= the length of the sequence, returns null.
-
subsequence
public GroundedValue subsequence(int start, int length)
Get a subsequence of the value- Specified by:
subsequence
in interfaceGroundedValue
- Parameters:
start
- the index of the first item to be included in the result, counting from zero. A negative value is taken as zero. If the value is beyond the end of the sequence, an empty sequence is returnedlength
- the number of items to be included in the result. Specify Integer.MAX_VALUE to get the subsequence up to the end of the base sequence. If the value is negative, an empty sequence is returned. If the value goes off the end of the sequence, the result returns items up to the end of the sequence- Returns:
- the required subsequence. If min is
-
getNode
public NodeInfo getNode()
Get the node that forms the node-set. Return null if there is none.
-
iterate
public SequenceIterator iterate()
Return an enumeration of this nodeset value.
-
effectiveBooleanValue
public boolean effectiveBooleanValue()
Get the effective boolean value- Overrides:
effectiveBooleanValue
in classValue
- Returns:
- the effective boolean value
-
getStringValue
public java.lang.String getStringValue()
Convert the value to a string, using the serialization rules. For atomic values this is the same as a cast; for sequence values it gives a space-separated list. For QNames and NOTATIONS, or lists containing them, it fails.- Specified by:
getStringValue
in interfaceValueRepresentation
- Overrides:
getStringValue
in classValue
-
-