net.sf.saxon.value
Class EmptySequence

java.lang.Object
  net.sf.saxon.value.Value
      net.sf.saxon.value.EmptySequence

All Implemented Interfaces:

Serializable, Comparable, SequenceIterable, ValueRepresentation

public final class EmptySequence
extends Value

An EmptySequence object represents a sequence containing no members.

See Also:

Serialized Form

Field Summary

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

Method Summary

Item	asItem() Return the value in the form of an Item
boolean	effectiveBooleanValue() Get the effective boolean value - always false
boolean	equals(Object other) Is this expression the same as another expression?
int	getCardinality() Determine the static cardinality
static EmptySequence	getInstance() Get the implicit instance of this class
ItemType	getItemType(TypeHierarchy th) Determine the item type
int	getLength() Get the length of the sequence
int	hashCode() Return a hash code to support the equals() function
boolean	isMultiValued() Determine whether the value is multivalued, that is, whether it is a sequence that potentially contains more than one item
SequenceIterator	iterate() Return an iteration over the sequence

Methods inherited from class net.sf.saxon.value.Value

asItem, asIterator, asValue, checkPermittedContents, compareTo, convert, convertJavaObjectToXPath, convertToJava, fromItem, getCanonicalLexicalRepresentation, getIterator, getSchemaComparable, getStringValue, getStringValueCS, itemAt, iterate, makeQNameValue, process, reduce, stringToNumber, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Method Detail

getInstance

public static EmptySequence getInstance()

Get the implicit instance of this class

isMultiValued

public boolean isMultiValued()

Determine whether the value is multivalued, that is, whether it is a sequence that potentially contains more than one item

Specified by:

isMultiValued in class Value

Returns:

true if the value might contain more than one item, false if it definitely contains zero or one items

iterate

public SequenceIterator iterate()

Return an iteration over the sequence

Specified by:

iterate in class Value

Returns:

an iterator over the sequence of items

asItem

public Item asItem()

Return the value in the form of an Item

Overrides:

asItem in class Value

Returns:

the value in the form of an Item

getItemType

public ItemType getItemType(TypeHierarchy th)

Determine the item type

Overrides:

getItemType in class Value

Parameters:

th -

Returns:

for the default implementation: AnyItemType (not known)

getCardinality

public int getCardinality()

Determine the static cardinality

Overrides:

getCardinality in class Value

getLength

public final int getLength()

Get the length of the sequence

Overrides:

getLength in class Value

Returns:

always 0 for an empty sequence

equals

public boolean equals(Object other)

Is this expression the same as another expression?

Overrides:

equals in class Value

Throws:

ClassCastException - if the values are not comparable

hashCode

public int hashCode()

Description copied from class: Value

Return a hash code to support the equals() function

Overrides:

hashCode in class Value

effectiveBooleanValue

public boolean effectiveBooleanValue()

Get the effective boolean value - always false

Overrides:

effectiveBooleanValue in class Value

Returns:

the effective boolean value