Class NullPointer

java.lang.Object

org.apache.commons.jxpath.ri.model.NodePointer

org.apache.commons.jxpath.ri.model.beans.PropertyOwnerPointer

org.apache.commons.jxpath.ri.model.beans.NullPointer

All Implemented Interfaces:

Serializable, Cloneable, Comparable, Pointer

public class NullPointer
extends PropertyOwnerPointer

Pointer whose value is null.

Version:

$Revision: 652915 $ $Date: 2008-05-02 16:12:57 -0500 (Fri, 02 May 2008) $

Author:

Dmitri Plotnikov

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private String	id
private QName	name
private static final long	serialVersionUID

Fields inherited from class NodePointer

index, locale, parent, UNKNOWN_NAMESPACE, WHOLE_COLLECTION

Constructor Summary

Constructors

Constructor	Description
NullPointer(Locale locale, String id)	Create a new NullPointer.
NullPointer(NodePointer parent, QName name)	Used for the root node.
NullPointer(QName name, Locale locale)	Create a new NullPointer.

Method Summary

Modifier and Type	Method	Description
String	asPath()	Returns an XPath that maps to this Pointer.
NodePointer	createChild(JXPathContext context, QName name, int index)	Called by a child pointer when it needs to create a parent object for a non-existent collection element.
NodePointer	createChild(JXPathContext context, QName name, int index, Object value)	Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node.
NodePointer	createPath(JXPathContext context)	Called by a child pointer when it needs to create a parent object.
NodePointer	createPath(JXPathContext context, Object value)	Called directly by JXPathContext.
boolean	equals(Object object)
Object	getBaseValue()	Returns the value represented by the pointer before indexing.
int	getLength()	If the pointer represents a collection (or collection element), returns the length of the collection.
QName	getName()	Returns the name of this node.
PropertyPointer	getPropertyPointer()	Get a PropertyPointer for this PropertyOwnerPointer.
int	hashCode()
boolean	isActual()	An actual pointer points to an existing part of an object graph, even if it is null.
boolean	isCollection()	Returns true if the value of the pointer is an array or a Collection.
boolean	isLeaf()	If true, this node does not have children

Methods inherited from class PropertyOwnerPointer

attributeIterator, childIterator, compareChildNodePointers, createNodeIterator, getImmediateNode, isDynamicPropertyDeclarationSupported, isValidProperty, remove, setIndex, setValue

Methods inherited from class NodePointer

clone, compareTo, createAttribute, escape, getAbstractFactory, getDefaultNamespaceURI, getImmediateParentPointer, getImmediateValuePointer, getIndex, getLocale, getNamespaceResolver, getNamespaceURI, getNamespaceURI, getNode, getNodeSetByKey, getNodeValue, getParent, getPointerByID, getPointerByKey, getRootNode, getValue, getValuePointer, isAttribute, isContainer, isDefaultNamespace, isLanguage, isNode, isRoot, namespaceIterator, namespacePointer, newChildNodePointer, newNodePointer, printPointerChain, setAttribute, setNamespaceResolver, testNode, toString

Methods inherited from class Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

name

private QName name

id

private String id

serialVersionUID

private static final long serialVersionUID

See Also:

• Constant Field Values

Constructor Details

NullPointer

public NullPointer(QName name,
 Locale locale)

Create a new NullPointer.

Parameters:

name - node name

locale - Locale

NullPointer

public NullPointer(NodePointer parent,
 QName name)

Used for the root node.

Parameters:

parent - parent pointer

name - node name

NullPointer

public NullPointer(Locale locale,
 String id)

Create a new NullPointer.

Parameters:

locale - Locale

id - String

Method Details

getName

public QName getName()

Description copied from class: NodePointer

Returns the name of this node. Can be null.

Specified by:

getName in class PropertyOwnerPointer

Returns:

QName

getBaseValue

public Object getBaseValue()

Description copied from class: NodePointer

Returns the value represented by the pointer before indexing. So, if the node represents an element of a collection, this method returns the collection itself.

Specified by:

getBaseValue in class NodePointer

Returns:

Object value

isCollection

public boolean isCollection()

Description copied from class: NodePointer

Returns true if the value of the pointer is an array or a Collection.

Specified by:

isCollection in class NodePointer

Returns:

boolean

isLeaf

public boolean isLeaf()

Description copied from class: NodePointer

If true, this node does not have children

Specified by:

isLeaf in class NodePointer

Returns:

boolean

isActual

public boolean isActual()

Description copied from class: NodePointer

An actual pointer points to an existing part of an object graph, even if it is null. A non-actual pointer represents a part that does not exist at all. For instance consider the pointer "/address/street". If both address and street are not null, the pointer is actual. If address is not null, but street is null, the pointer is still actual. If address is null, the pointer is not actual. (In JavaBeans) if address is not a property of the root bean, a Pointer for this path cannot be obtained at all - actual or otherwise.

Overrides:

isActual in class NodePointer

Returns:

boolean

getPropertyPointer

public PropertyPointer getPropertyPointer()

Description copied from class: PropertyOwnerPointer

Get a PropertyPointer for this PropertyOwnerPointer.

Specified by:

getPropertyPointer in class PropertyOwnerPointer

Returns:

PropertyPointer

createPath

public NodePointer createPath(JXPathContext context,
 Object value)

Description copied from class: NodePointer

Called directly by JXPathContext. Must create path and set value.

Overrides:

createPath in class NodePointer

Parameters:

context - the owning JXPathContext

value - the new value to set

Returns:

created NodePointer

createPath

public NodePointer createPath(JXPathContext context)

Description copied from class: NodePointer

Called by a child pointer when it needs to create a parent object. Must create an object described by this pointer and return a new pointer that properly describes the new object.

Overrides:

createPath in class NodePointer

Parameters:

context - the owning JXPathContext

Returns:

created NodePointer

createChild

public NodePointer createChild(JXPathContext context,
 QName name,
 int index)

Description copied from class: NodePointer

Called by a child pointer when it needs to create a parent object for a non-existent collection element. It may have to expand the collection, then create an element object and return a new pointer describing the newly created element.

Overrides:

createChild in class NodePointer

Parameters:

context - the owning JXPathCOntext

name - the QName at which a child should be created

index - child index.

Returns:

created NodePointer

createChild

public NodePointer createChild(JXPathContext context,
 QName name,
 int index,
 Object value)

Description copied from class: NodePointer

Called by a child pointer if that child needs to assign the value supplied in the createPath(context, value) call to a non-existent node. This method may have to expand the collection in order to assign the element.

Overrides:

createChild in class NodePointer

Parameters:

context - the owning JXPathCOntext

name - the QName at which a child should be created

index - child index.

value - node value to set

Returns:

created NodePointer

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object object)

Overrides:

equals in class Object

asPath

public String asPath()

Description copied from class: NodePointer

Returns an XPath that maps to this Pointer.

Specified by:

asPath in interface Pointer

Overrides:

asPath in class NodePointer

Returns:

String xpath expression

getLength

public int getLength()

Description copied from class: NodePointer

If the pointer represents a collection (or collection element), returns the length of the collection. Otherwise returns 1 (even if the value is null).

Specified by:

getLength in class NodePointer

Returns:

int