java.lang.Object
- net.sf.saxon.s9api.XdmValue

All Implemented Interfaces:

java.lang.Iterable<XdmItem>

Direct Known Subclasses:

XdmEmptySequence, XdmItem
```
public class XdmValue
extends java.lang.Object
implements java.lang.Iterable<XdmItem>
```
A value in the XDM data model. A value is a sequence of zero or more items, each item being an atomic value, a node, or a function item.
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	Description
	`XdmValue(java.lang.Iterable<? extends XdmItem> items)`	Create an XdmValue as a sequence of XdmItem objects
	`XdmValue(java.util.Iterator<? extends XdmItem> iterator)`	Create an XdmValue containing the items returned by an `Iterator`.
	`XdmValue(java.util.stream.Stream<? extends XdmItem> stream)`	Create an XdmValue containing the results of reading a Stream
`protected`	`XdmValue(GroundedValue value)`	Create an XdmValue that wraps a supplied `GroundedValue`.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`XdmValue`	`append(XdmValue otherValue)`	Create a new XdmValue by concatenating the contents of this XdmValue and another XdmValue into a single sequence.
`XdmValue`	`documentOrder()`	Return a new XdmValue containing the nodes present in this XdmValue, with duplicates eliminated, and sorted into document order
`GroundedValue`	`getUnderlyingValue()`	Get the underlying implementation object representing the value.
`boolean`	`isEmpty()`	Ask whether the sequence is empty
`XdmItem`	`itemAt(int n)`	Get the n'th item in the value, counting from zero.
`XdmSequenceIterator<XdmItem>`	`iterator()`	Get an iterator over the items in this value.
`static XdmValue`	`makeSequence(java.lang.Iterable<?> list)`	Make an XDM sequence from a Java `Iterable`.
`static XdmValue`	`makeValue(java.lang.Object o)`	Make an XDM value from a Java object.
`boolean`	`matches(SequenceType type)`	Test whether the value matches a supplied SequenceType
`<T extends XdmItem> XdmStream<T>`	`select(Step<T> step)`	Get a stream of items by applying a `Step` to the items in this value.
`int`	`size()`	Get the number of items in the sequence
`XdmStream<? extends XdmItem>`	`stream()`	Get a stream comprising the items in this value
`XdmValue`	`subsequence(int start, int length)`	Get a subsequence of the value
`java.lang.String`	`toString()`	Create a string representation of the value.
`XdmValue`	`where(java.util.function.Predicate<? super XdmItem> predicate)`	Filter the value on a supplied predicate
`static XdmValue`	`wrap(AtomicSequence value)`
`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, wait, wait, wait

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Constructor Detail
  - XdmValue
```
protected XdmValue(GroundedValue value)
```
    Create an XdmValue that wraps a supplied GroundedValue. This method is primarily for internal use, though it is also available to applications that manipulate data using lower-level Saxon interfaces.
    Note that this constructor necessarily produces an XdmValue regardless of the supplied value. To construct instances of subclasses of XdmValue, such as XdmAtomicValue or XdmNode, use the wrap(net.sf.saxon.om.Sequence) method, or use the overriding constructor on the required subclass.
    
    Parameters:
    
    value - the value to be wrapped.
  - XdmValue
```
public XdmValue(java.lang.Iterable<? extends 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
```
public XdmValue(java.util.Iterator<? extends XdmItem> iterator)
         throws SaxonApiException
```
    Create an XdmValue containing the items returned by an Iterator.
    
    Parameters:
    
    iterator - the iterator that supplies the values
    
    Throws:
    
    SaxonApiException - if an error occurs reading values from the supplied iterator
    
    Since:
    
    9.6. Extended in 9.9 to take any Iterator, not just an XdmSequenceIterator.
  - XdmValue
```
public XdmValue(java.util.stream.Stream<? extends XdmItem> stream)
         throws SaxonApiException
```
    Create an XdmValue containing the results of reading a Stream
    
    Parameters:
    
    stream - the stream to be read
    
    Throws:
    
    SaxonApiException - if an error occurs reading values from the supplied stream
- Method Detail
  - 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 map, the result will be an instance of XdmMap.
    
    If the supplied value is an array, the result will be an instance of XdmArray.
    
    If the supplied value is a function item, 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)
  - wrap
```
public static XdmValue wrap(AtomicSequence value)
```
  - append
```
public XdmValue append(XdmValue otherValue)
```
    Create a new XdmValue by concatenating the contents of this XdmValue and another XdmValue into a single sequence. 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, considered as a sequence. Note that for arrays and maps, the answer will be 1 (one) since arrays and maps are items.
  - isEmpty
```
public boolean isEmpty()
```
    Ask whether the sequence is empty
    
    Returns:
    
    true if the value is an empty sequence
    
    Since:
    
    10.1
  - itemAt
```
public XdmItem itemAt(int n)
               throws java.lang.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:
    
    java.lang.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.
  - subsequence
```
public XdmValue subsequence(int start,
                            int length)
```
    Get a subsequence of the value
    
    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 returned
    
    length - 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 length goes off the end of the sequence, the result returns items up to the end of the sequence
    
    Returns:
    
    the required subsequence.
    
    Since:
    
    11
  - iterator
```
public XdmSequenceIterator<XdmItem> iterator()
                                      throws SaxonApiUncheckedException
```
    Get an iterator over the items in this value.
    
    Specified by:
    
    iterator in interface java.lang.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 GroundedValue 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
  - toString
```
public java.lang.String toString()
```
    Create a string representation of the value. The is the result of serializing the value using the adaptive serialization method, with the options indent="yes" and omit-xml-declaration="yes". The item-separator if there are multiple items is a newline. Any trailing newline in the result is removed.
    Note that this method does not return the same result as the XPath fn:string() function: it corresponds more closely to the fn:serialize() function.
    
    If the XdmValue is an element node, the result will be a well-formed XML document serialized as defined in the W3C XSLT/XQuery serialization specification, using options method="xml", indent="yes", omit-xml-declaration="yes".
    
    In the case of a document node, the result will be a well-formed XML document provided that the document node contains exactly one element child, and no text node children.
    
    In the case of an attribute node, the output is a string in the form name="value". The name will use the original namespace prefix.
    
    In the case of a namespace node, the output is a string in the form of a namespace declaration, that is xmlns="uri" or xmlns:pre="uri".
    
    Other nodes, such as text nodes, comments, and processing instructions, are represented as they would appear in lexical XML. Note: this means that in the case of text nodes, special characters such as & and < are output in escaped form. To get the unescaped string value of a text node, use XdmItem.getStringValue() instead.
    
    Atomic values are serialized according to the rules of the adaptive output method, for example true(), "blue", 42, or xs:date("2023-01-31").
    
    A sequence of items is formatted by serializing the individual items, separated by newlines.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    a string representation of the value
  - makeSequence
```
public static XdmValue makeSequence(java.lang.Iterable<?> list)
                             throws java.lang.IllegalArgumentException
```
    Make an XDM sequence from a Java Iterable. Each value delivered by the iterable is first converted to an XDM value using the makeValue(Object) method; if the result is anything other than a single XDM item, it is then wrapped in an XdmArray.
    
    Parameters:
    
    list - the Java iterable
    
    Returns:
    
    the result of the conversion if successful
    
    Throws:
    
    java.lang.IllegalArgumentException - if conversion is not possible
  - makeValue
```
public static XdmValue makeValue(java.lang.Object o)
                          throws java.lang.IllegalArgumentException
```
    Make an XDM value from a Java object. The supplied object may be any of the following:
    
    An instance of XdmValue (for example, an XdmNode or XdmAtomicValue or XdmArray or XdmMap), which is returned unchanged
    
    An instance of Sequence (for example, a NodeInfo or AtomicValue), which is wrapped as an XdmValue
    
    An instance of Map, which is converted to an XDM Map using the XdmMap.makeMap(java.util.Map<K, V>) method
    
    A Java array, of any type, which is converted to an XDM Array using the XdmArray.makeArray(java.lang.Object[]) method
    
    A Java collection, more specifically Iterable, which is converted to an XDM sequence using the makeSequence(Iterable) method
    
    Any object that is convertible to an XDM atomic value using the method XdmAtomicValue.makeAtomicValue(Object)
    Parameters:
    
    o - the Java object
    
    Returns:
    
    the result of the conversion if successful
    
    Throws:
    
    java.lang.IllegalArgumentException - if conversion is not possible
  - documentOrder
```
public XdmValue documentOrder()
                       throws SaxonApiException
```
    Return a new XdmValue containing the nodes present in this XdmValue, with duplicates eliminated, and sorted into document order
    
    Returns:
    
    the same nodes, sorted into document order, with duplicates eliminated
    
    Throws:
    
    SaxonApiException - if anything goes wrong (typically during delayed evaluation of the input sequence)
    
    java.lang.ClassCastException - if the sequence contains items that are not nodes
    
    Since:
    
    9.9
  - stream
```
public XdmStream<? extends XdmItem> stream()
```
    Get a stream comprising the items in this value
    
    Returns:
    
    a Stream over the items in this value
    
    Since:
    
    9.9
  - select
```
public <T extends XdmItem> XdmStream<T> select(Step<T> step)
```
    Get a stream of items by applying a Step to the items in this value. This operation is analogous to the Stream.flatMap operation in Java, or to the "!" operator in XPath.
    The following examples assume a static import declaration of the standard Steps: import static net.sf.saxon.s9api.streams.Steps.*;
    
    select(child()) returns a stream containing all children
    
    select(child("*")) returns a stream containing all element children
    
    select(child("author")) returns a stream containing all element children with local name "author" (regardless of namespace)
    
    select(child("http://my.ns/", "author")) returns a stream containing all element children with local name "author" and namespace "http://my.ns/"
    
    select(descendant("author")) returns a stream containing all element descendants with local name "author" (regardless of namespace)
    
    select(descendant("author").then(attribute("name")) returns a stream containing the "name" attributes of "author" descendants
    
    select(path("//", "author", "@name")) returns a stream containing the "name" attributes of "author" descendants
    
    select(child("author").where(attributeEq("firstName", "Jane")) returns a stream containing all the "author" children having a "firstName" attribute whose value is "Jane"
    
    select(child("author").first()) returns a stream containing the first "author" child (if there is one)
    
    select(child("author").where(attributeEq("firstName", "Jane").last()) returns a stream containing the last "author" child having a "firstName" attribute whose value is "Jane" (if there is one)
    
    In each of the above examples, the selected nodes are returned as an XdmStream<XdmNode>; this class extends Stream<XdmNode>, so all the standard operations on streams are available, together with some additional operations specific to node streams.
    
    The select method thus has comparable power to simple XPath expressions; but unlike XPath expressions, there is no run-time overhead in parsing the XPath expression and developing an execution plan.
    Type Parameters:
    
    T - the type of items to be returned by the step (often XdmNode)
    
    Parameters:
    
    step - the Step to be applied to the items in this value. This will often be one of the standard steps returned by the static methods of the Steps class, such as Steps.child(), or by instance methods (such as Step.where(java.util.function.Predicate<? super T>), Step.cat(net.sf.saxon.s9api.streams.Step<T>), or Step.first()) but it is also possible to create user-defined steps.
    
    Returns:
    
    a Stream of items obtained by replacing each item X in this value by the items obtained by applying the Step function to X.
    
    Since:
    
    9.9
  - where
```
public XdmValue where(java.util.function.Predicate<? super XdmItem> predicate)
```
    Filter the value on a supplied predicate
    
    Parameters:
    
    predicate - the predicate to be applied. Note that an ItemType is a predicate, so this method can be used to select those items that match a supplied item type. For example, where(ItemType.INTEGER) will select the items in the sequence that are instances of xs:integer.
    
    Returns:
    
    a new XdmValue comprising those items in this XdmValue that match the given predicate.
    
    Since:
    
    12.0
  - matches
```
public boolean matches(SequenceType type)
```
    Test whether the value matches a supplied SequenceType
    
    Parameters:
    
    type - the SequenceType that we are testing against
    
    Returns:
    
    true if this value matches the sequence type, false otherwise.
    
    Since:
    
    12.0

Class XdmValue

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Constructor Detail

XdmValue

XdmValue

XdmValue

XdmValue

Method Detail

wrap

wrap

append

size

isEmpty

itemAt

subsequence

iterator

getUnderlyingValue

toString

makeSequence

makeValue

documentOrder

stream

select

where

matches