net.sf.saxon.s9api

Class XdmValue

java.lang.Object

net.sf.saxon.s9api.XdmValue

All Implemented Interfaces:

Iterable<XdmItem>

Direct Known Subclasses:

XdmEmptySequence, XdmItem

public class XdmValue
extends Object
implements Iterable<XdmItem>

An value in the XDM data model. A value is a sequence of zero or more items, each item being either an atomic value or a node.

An XdmValue is immutable.

A sequence consisting of a single item may be represented as an instance of XdmItem, which is a subtype of XdmValue. However, there is no guarantee that a sequence of length one will always be an instance of XdmItem.

Similarly, a zero-length sequence may be represented as an instance of XdmEmptySequence, but there is no guarantee that every sequence of length zero will always be an instance of XdmEmptySequence.

Since:

9.0

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	XdmValue()
	XdmValue(Iterable<XdmItem> items) Create an XdmValue as a sequence of XdmItem objects
protected	XdmValue(Sequence value)

Method Summary

Methods

Modifier and Type	Method and Description
XdmValue	append(XdmValue otherValue) Create a new XdmValue by concatenating the contents of this XdmValue and another XdmValue.
Sequence	getUnderlyingValue() Get the underlying implementation object representing the value.
XdmItem	itemAt(int n) Get the n'th item in the value, counting from zero.
XdmSequenceIterator	iterator() Get an iterator over the items in this value.
protected void	setValue(Sequence value)
int	size() Get the number of items in the sequence
static XdmValue	wrap(Sequence value) Create an XdmValue that wraps an existing Saxon Sequence

Methods inherited from class java.lang.Object

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

Constructor Detail

XdmValue

protected XdmValue()

XdmValue

public XdmValue(Iterable<XdmItem> items)

Create an XdmValue as a sequence of XdmItem objects

Parameters:

items - a sequence of XdmItem objects. Note that if this is supplied as a list or similar collection, subsequent changes to the list/collection will have no effect on the XdmValue.

Since:

9.0.0.4

XdmValue

protected XdmValue(Sequence value)

Method Detail

setValue

protected void setValue(Sequence value)

wrap

public static XdmValue wrap(Sequence value)

Create an XdmValue that wraps an existing Saxon Sequence

Parameters:

value - the supplied Sequence (which may be a singleton Item),

Returns:

an XdmValue corresponding to the supplied Sequence. If the supplied value is null, an empty sequence is returned. If the supplied value is an atomic value, the result will be an instance of XdmAtomicValue. If the supplied value is a node, the result will be an instance of XdmNode. If the supplied value is a function item (including map items), the result will be an instance of XdmFunctionItem.

Throws:

SaxonApiUncheckedException - if the supplied Sequence is not yet fully evaluated, and evaluation of the underlying expression fails with a dynamic error.

Since:

9.5 (previously a protected method)

append

public XdmValue append(XdmValue otherValue)

Create a new XdmValue by concatenating the contents of this XdmValue and another XdmValue. The two input XdmValue objects are unaffected by this operation.

Note: creating a sequence of N values by successive calls on this method takes time proportional to N-squared.

Parameters:

otherValue - the value to be appended

Returns:

a new XdmValue containing the concatenation of the two input XdmValue objects

Since:

9.2

size

public int size()

Get the number of items in the sequence

Returns:

the number of items in the value

Throws:

SaxonApiUncheckedException - if the value is lazily evaluated and the delayed evaluation fails with a dynamic error.

itemAt

public XdmItem itemAt(int n)
               throws IndexOutOfBoundsException,
                      SaxonApiUncheckedException

Get the n'th item in the value, counting from zero.

Parameters:

n - the item that is required, counting the first item in the sequence as item zero

Returns:

the n'th item in the sequence making up the value, counting from zero

Throws:

IndexOutOfBoundsException - if n is less than zero or greater than or equal to the number of items in the value

SaxonApiUncheckedException - if the value is lazily evaluated and the delayed evaluation fails with a dynamic error.

iterator

public XdmSequenceIterator iterator()
                             throws SaxonApiUncheckedException

Get an iterator over the items in this value.

Specified by:

iterator in interface Iterable<XdmItem>

Returns:

an Iterator over the items in this value.

Throws:

SaxonApiUncheckedException - if the value is lazily evaluated and the delayed evaluation fails with a dynamic error.

getUnderlyingValue

public Sequence getUnderlyingValue()

Get the underlying implementation object representing the value. This method allows access to lower-level Saxon functionality, including classes and methods that offer no guarantee of stability across releases.

Returns:

the underlying implementation object representing the value