XdmItem Class Reference

The class XdmItem represents an item in a sequence, as defined by the XDM data model. More...

#include <XdmItem.h>

Inheritance diagram for XdmItem:

Public Member Functions
	XdmItem ()
	Default constructor.
	XdmItem (int64_t objRef)
	XdmItem constructor to create an object which is a wrapper for a Java XdmItem object - internal use only.
	XdmItem (const XdmItem &item)
	XdmItem copy constructor.
bool	operator== (const XdmItem &other) const
virtual	~XdmItem ()
	Destructor method for XdmItem.
virtual void	incrementRefCount ()
	Increment reference count of this XdmItem - internal use only.
virtual void	decrementRefCount ()
	Decrement reference count of this XdmItem - internal use only.
virtual bool	isAtomic ()
	Determine whether the item is an atomic value or some other type of item.
virtual bool	isNode ()
	Determine whether the item is a node or some other type of item.
virtual bool	isFunction ()
	Determine whether the item is an XDM function or some other type of item.
virtual bool	isMap ()
	Determine whether the item is an XDM map or some other type of item.
virtual bool	isArray ()
	Determine whether the item is an XDM array or some other type of item.
virtual int64_t	getUnderlyingValue ()
	Get the underlying Java XdmValue object - internal use only.
virtual const char *	getStringValue (const char *encoding=nullptr)
	Get the string value of the item.
const char *	toString (const char *encoding=nullptr)
	Create a string representation of the item.
virtual XdmItem *	getHead ()
	Get the first item in the sequence consisting of just this item.
XdmItem *	itemAt (int n)
	Get the n'th item in the sequence consisting of just this item, counting from zero.
int	size ()
	Get the number of items in the sequence.
virtual XDM_TYPE	getType ()
	Get the type of this XDM value.
Public Member Functions inherited from XdmValue
	XdmValue ()
	Default constructor.
	XdmValue (const XdmValue &other)
	XdmValue copy constructor.
void	addXdmItem (XdmItem *val)
	Add an XdmItem to the sequence.
virtual bool	operator== (const XdmValue &other) const
void	addXdmItemFromUnderlyingValue (XdmItem *val)
	Add an XdmItem to the sequence, when the sequence was returned from SaxonC - internal use only.
void	addUnderlyingValue (int64_t val)
	Add Java XdmValue object to the sequence.
	XdmValue (int64_t val, bool arrFlag)
	A Constructor for handling XdmArray - internal use only.
	XdmValue (int64_t val)
	XdmValue constructor to create an object which is a wrapper for a Java XdmValue object - internal use only.
virtual	~XdmValue ()
	Destructor method for XdmValue.
void	releaseXdmValue ()
	Deprecated: this is deprecated and a no-op, the C++ destructor handles this case.
int	getRefCount ()
	Get the number of references on this XdmValue - internal use only This method is used for internal memory management.
void	resetRelinquishedItems ()
	Reset associated reference counts on XdmItems that have been relinquished - internal use only.
void	incrementRefCountForRelinquishedValue (int i)
	Increment the ref count for a relinquished item only once - internal use only.

Protected Attributes
const char *	stringValue
const char *	itemToString
Protected Attributes inherited from XdmValue
char *	valueType
XdmItem **	values
char *	relinquished_values
int	values_cap
int	xdmSize
int	refCount
int64_t	value

Additional Inherited Members
Protected Member Functions inherited from XdmValue
void	initialize ()
	Initialize this XdmValue with default values.

Detailed Description

The class XdmItem represents an item in a sequence, as defined by the XDM data model.

An item is either an atomic value, a node, or a function item.

An item is a member of a sequence, but it can also be considered as a sequence (of length one) in its own right. XdmItem is a subtype of XdmValue because every item in the XDM data model is also a value.

It cannot be assumed that every sequence of length one will be represented by an XdmItem. It is quite possible for an XdmValue that is not an XdmItem to hold a singleton sequence.

Saxon provides a number of concrete subclasses of XdmItem, namely XdmNode, XdmAtomicValue and XdmFunctionItem. Users must not attempt to create additional subclasses.

Constructor & Destructor Documentation

XdmItem() [1/3]

XdmItem::XdmItem

(

)

Default constructor.

Creates an empty XdmItem.

XdmItem() [2/3]

XdmItem::XdmItem ( int64_t objRef )

explicit

XdmItem constructor to create an object which is a wrapper for a Java XdmItem object - internal use only.

Parameters

objRef

- internal Java XdmItem object to be wrapped

XdmItem() [3/3]

XdmItem::XdmItem

(

const XdmItem &

item

)

XdmItem copy constructor.

Parameters

item

- XdmItem

Member Function Documentation

decrementRefCount()

void XdmItem::decrementRefCount ( )

virtual

Decrement reference count of this XdmItem - internal use only.

This method is used for internal memory management.

Reimplemented from XdmValue.

getHead()

XdmItem * XdmItem::getHead ( )

virtual

Get the first item in the sequence consisting of just this item.

Returns

This XdmItem

Reimplemented from XdmValue.

Reimplemented in XdmAtomicValue, and XdmNode.

getStringValue()

const char * XdmItem::getStringValue ( const char * encoding = nullptr )

virtual

Get the string value of the item.

For a node, this gets the string value of the node. For an atomic value, it has the same effect as casting the value to a string. For a function item, there is no string value, so an exception is thrown. In all cases the result is the same as applying the XPath string() function.

For atomic values, the result is the same as the result of calling toString. This is not the case for nodes, where toString returns an XML serialization of the node. The caller is responsible for memory deallocation using operator delete.

Parameters

encoding

- the encoding of the string returned. If NULL or omitted it defaults to the JVM encoding, which in most cases is UTF-8.

Returns

The result of converting the item to a string.

Exceptions

SaxonApiException

if the item is a function

Reimplemented in XdmArray, XdmAtomicValue, XdmFunctionItem, and XdmNode.

getType()

XDM_TYPE XdmItem::getType ( )

virtual

Get the type of this XDM value.

Returns

The type of the XdmValue as an XDM_TYPE

Reimplemented from XdmValue.

Reimplemented in XdmArray, XdmAtomicValue, XdmFunctionItem, XdmMap, and XdmNode.

getUnderlyingValue()

int64_t XdmItem::getUnderlyingValue ( )

virtual

Get the underlying Java XdmValue object - internal use only.

Returns

The Java object of the XdmValue in its JNI representation

Reimplemented from XdmValue.

Reimplemented in XdmNode.

incrementRefCount()

void XdmItem::incrementRefCount ( )

virtual

Increment reference count of this XdmItem - internal use only.

This method is used for internal memory management.

Reimplemented from XdmValue.

isArray()

bool XdmItem::isArray ( )

virtual

Determine whether the item is an XDM array or some other type of item.

Returns

True if the item is an XDM Array item, false if it is some other item

Reimplemented in XdmArray.

isAtomic()

bool XdmItem::isAtomic ( )

virtual

Determine whether the item is an atomic value or some other type of item.

Returns

True if the item is an atomic value, false if it is a node or a function (including maps and arrays)

Reimplemented in XdmAtomicValue, XdmFunctionItem, and XdmNode.

isFunction()

bool XdmItem::isFunction ( )

virtual

Determine whether the item is an XDM function or some other type of item.

Returns

True if the item is an XDM function item (including maps and arrays), false if it is an atomic value or a node

Reimplemented in XdmArray, XdmFunctionItem, and XdmMap.

isMap()

bool XdmItem::isMap ( )

virtual

Determine whether the item is an XDM map or some other type of item.

Returns

True if the item is an XDM map item, false if it is some other item

Reimplemented in XdmMap.

isNode()

bool XdmItem::isNode ( )

virtual

Determine whether the item is a node or some other type of item.

Returns

True if the item is a node, false if it is an atomic value or a function (including maps and arrays)

Reimplemented in XdmNode.

itemAt()

XdmItem * XdmItem::itemAt ( int n )

virtual

Get the n'th item in the sequence consisting of just this item, counting from zero.

Parameters

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

Returns

If n is zero, then return this XdmItem. Otherwise return nullptr if n is not zero, or if the value is lazily evaluated and the delayed evaluation fails with a dynamic error. The caller is responsible for memory deallocation.

Reimplemented from XdmValue.

size()

int XdmItem::size ( )

virtual

Get the number of items in the sequence.

Returns

The number of items in the XdmValue. For an XdmItem this is always 1 (one).

Reimplemented from XdmValue.

toString()

const char * XdmItem::toString ( const char * encoding = nullptr )

virtual

Create a string representation of the item.

This is the result of serializing the item using the adaptive serialization method.

Parameters

encoding

- the encoding of the string returned. If NULL or omitted it defaults to the JVM encoding, which in most cases is UTF-8.

Returns

A string representation of the XdmItem. The caller is responsible for memory deallocation using operator delete.

Reimplemented from XdmValue.

Reimplemented in XdmMap, and XdmNode.

Member Data Documentation

itemToString

const char* XdmItem::itemToString

protected

Cached. String representation of the XdmValue, if available

stringValue

const char* XdmItem::stringValue

protected

Cached. String representation of the XdmValue, if available

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The documentation for this class was generated from the following files:

• /Users/debbie/Work/refactor/saxon12/libsaxonc/src/include/saxonc/XdmItem.h
• /Users/debbie/Work/refactor/saxon12/libsaxonc/src/lib/XdmItem.cpp