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

java.lang.Object
  org.apache.commons.jxpath.ri.model.NodePointer

All Implemented Interfaces:

java.lang.Cloneable, java.lang.Comparable, Pointer, java.io.Serializable

Direct Known Subclasses:

CollectionPointer, ContainerPointer, DOMAttributePointer, DOMNodePointer, JDOMAttributePointer, JDOMNamespacePointer, JDOMNodePointer, LangAttributePointer, NamespacePointer, PropertyOwnerPointer, PropertyPointer, VariablePointer

public abstract class NodePointer

extends java.lang.Object

implements Pointer

Common superclass for Pointers of all kinds. A NodePointer maps to a deterministic XPath that represents the location of a node in an object graph. This XPath uses only simple axes: child, namespace and attribute and only simple, context-independent predicates.

Version:

$Revision: 1.25 $ $Date: 2004/04/01 02:55:32 $

Author:

Dmitri Plotnikov

See Also:

Serialized Form

Field Summary

private boolean	attribute
protected int	index
protected java.util.Locale	locale
private NamespaceResolver	namespaceResolver
protected NodePointer	parent
private java.lang.Object	rootNode
static java.lang.String	UNKNOWN_NAMESPACE
static int	WHOLE_COLLECTION

Constructor Summary

protected	NodePointer(NodePointer parent)
protected	NodePointer(NodePointer parent, java.util.Locale locale)

Method Summary

java.lang.String	asPath() Returns an XPath that maps to this Pointer.
NodeIterator	attributeIterator(QName qname) Returns a NodeIterator that iterates over all attributes of the current node matching the supplied node name (could have a wildcard).
NodeIterator	childIterator(NodeTest test, boolean reverse, NodePointer startWith) Returns a NodeIterator that iterates over all children or all children that match the given NodeTest, starting with the specified one.
java.lang.Object	clone() Pointers are cloneable
abstract int	compareChildNodePointers(NodePointer pointer1, NodePointer pointer2) Compares two child NodePointers and returns a positive number, zero or a positive number according to the order of the pointers.
private int	compareNodePointers(NodePointer p1, int depth1, NodePointer p2, int depth2)
int	compareTo(java.lang.Object object)
NodePointer	createAttribute(JXPathContext context, QName name) Called to create a non-existing attribute
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, java.lang.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, java.lang.Object value) Called directly by JXPathContext.
private static boolean	equalStrings(java.lang.String s1, java.lang.String s2)
abstract java.lang.Object	getBaseValue() Returns the value represented by the pointer before indexing.
protected java.lang.String	getDefaultNamespaceURI()
abstract java.lang.Object	getImmediateNode() Returns the object the pointer points to; does not convert it to a "canonical" type.
NodePointer	getImmediateParentPointer()
NodePointer	getImmediateValuePointer()
int	getIndex() If the pointer represents a collection, the index identifies an element of that collection.
abstract int	getLength() If the pointer represents a collection (or collection element), returns the length of the collection.
java.util.Locale	getLocale() If the Pointer has a parent, returns the parent's locale; otherwise returns the locale specified when this Pointer was created.
abstract QName	getName() Returns the name of this node.
NamespaceResolver	getNamespaceResolver()
java.lang.String	getNamespaceURI() Returns the namespace URI associated with this Pointer.
java.lang.String	getNamespaceURI(java.lang.String prefix) Decodes a namespace prefix to the corresponding URI.
java.lang.Object	getNode() Returns the object the pointer points to; does not convert it to a "canonical" type.
java.lang.Object	getNodeValue() Deprecated. 1.1 Please use getNode()
NodePointer	getParent()
Pointer	getPointerByID(JXPathContext context, java.lang.String id) Locates a node by ID.
Pointer	getPointerByKey(JXPathContext context, java.lang.String key, java.lang.String value) Locates a node by key and value.
java.lang.Object	getRootNode() Returns the node this pointer is based on.
java.lang.Object	getValue() By default, returns getNode(), can be overridden to return a "canonical" value, like for instance a DOM element should return its string value.
NodePointer	getValuePointer() If this pointer manages a transparent container, like a variable, this method returns the pointer to the contents.
boolean	isActual() An actual pointer points to an existing part of an object graph, even if it is null.
boolean	isAttribute() Returns true if the pointer represents the "attribute::" axis.
abstract boolean	isCollection() Returns true if the value of the pointer is an array or a Collection.
boolean	isContainer() If true, this node is axiliary and can only be used as an intermediate in the chain of pointers.
protected boolean	isDefaultNamespace(java.lang.String prefix) Returns true if the supplied prefix represents the default namespace in the context of the current node.
boolean	isLanguage(java.lang.String lang) Returns true if the selected locale name starts with the specified prefix lang, case-insensitive.
abstract boolean	isLeaf() If true, this node does not have children
boolean	isNode() Deprecated. Please use !isContainer()
boolean	isRoot() Returns true if this Pointer has no parent.
NodeIterator	namespaceIterator() Returns a NodeIterator that iterates over all namespaces of the value currently pointed at.
NodePointer	namespacePointer(java.lang.String namespace) Returns a NodePointer for the specified namespace.
static NodePointer	newChildNodePointer(NodePointer parent, QName name, java.lang.Object bean) Allocates an new child NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.
static NodePointer	newNodePointer(QName name, java.lang.Object bean, java.util.Locale locale) Allocates an entirely new NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.
private static void	printDeep(NodePointer pointer, java.lang.String indent)
void	printPointerChain() Print internal structure of a pointer for debugging
void	remove() Remove the node of the object graph this pointer points to.
void	setAttribute(boolean attribute) Set to true if the pointer represents the "attribute::" axis.
void	setIndex(int index)
void	setNamespaceResolver(NamespaceResolver namespaceResolver)
abstract void	setValue(java.lang.Object value) Converts the value to the required type and changes the corresponding object to that value.
boolean	testNode(NodeTest test) Checks if this Pointer matches the supplied NodeTest.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

WHOLE_COLLECTION

public static final int WHOLE_COLLECTION

See Also:

Constant Field Values

index

protected int index

UNKNOWN_NAMESPACE

public static final java.lang.String UNKNOWN_NAMESPACE

See Also:

Constant Field Values

attribute

private boolean attribute

rootNode

private transient java.lang.Object rootNode

namespaceResolver

private NamespaceResolver namespaceResolver

parent

protected NodePointer parent

locale

protected java.util.Locale locale

Constructor Detail

NodePointer

protected NodePointer(NodePointer parent)

NodePointer

protected NodePointer(NodePointer parent,
                      java.util.Locale locale)

Method Detail

newNodePointer

public static NodePointer newNodePointer(QName name,
                                         java.lang.Object bean,
                                         java.util.Locale locale)

Allocates an entirely new NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.

newChildNodePointer

public static NodePointer newChildNodePointer(NodePointer parent,
                                              QName name,
                                              java.lang.Object bean)

Allocates an new child NodePointer by iterating through all installed NodePointerFactories until it finds one that can create a pointer.

getNamespaceResolver

public NamespaceResolver getNamespaceResolver()

setNamespaceResolver

public void setNamespaceResolver(NamespaceResolver namespaceResolver)

getParent

public NodePointer getParent()

getImmediateParentPointer

public NodePointer getImmediateParentPointer()

setAttribute

public void setAttribute(boolean attribute)

Set to true if the pointer represents the "attribute::" axis.

isAttribute

public boolean isAttribute()

Returns true if the pointer represents the "attribute::" axis.

isRoot

public boolean isRoot()

Returns true if this Pointer has no parent.

isLeaf

public abstract boolean isLeaf()

If true, this node does not have children

isNode

public boolean isNode()

Deprecated. Please use !isContainer()

isContainer

public boolean isContainer()

If true, this node is axiliary and can only be used as an intermediate in the chain of pointers.

getIndex

public int getIndex()

If the pointer represents a collection, the index identifies an element of that collection. The default value of index is WHOLE_COLLECTION, which just means that the pointer is not indexed at all. Note: the index on NodePointer starts with 0, not 1.

setIndex

public void setIndex(int index)

isCollection

public abstract boolean isCollection()

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

getLength

public abstract int getLength()

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

getValue

public java.lang.Object getValue()

By default, returns getNode(), can be overridden to return a "canonical" value, like for instance a DOM element should return its string value.

Specified by:

getValue in interface Pointer

getValuePointer

public NodePointer getValuePointer()

If this pointer manages a transparent container, like a variable, this method returns the pointer to the contents. Only an auxiliary (non-node) pointer can (and should) return a value pointer other than itself. Note that you probably don't want to override getValuePointer() directly. Override the getImmediateValuePointer() method instead. The getValuePointer() method is calls getImmediateValuePointer() and, if the result is not this, invokes getValuePointer() recursively. The idea here is to open all nested containers. Let's say we have a container within a container within a container. The getValuePointer() method should then open all those containers and return the pointer to the ultimate contents. It does so with the above recursion.

getImmediateValuePointer

public NodePointer getImmediateValuePointer()

See Also:

* @return NodePointer is either this or a pointer for the immediately contained value.

isActual

public boolean isActual()

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.

getName

public abstract QName getName()

Returns the name of this node. Can be null.

getBaseValue

public abstract java.lang.Object getBaseValue()

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.

getNodeValue

public java.lang.Object getNodeValue()

Deprecated. 1.1 Please use getNode()

Returns the object the pointer points to; does not convert it to a "canonical" type.

getNode

public java.lang.Object getNode()

Returns the object the pointer points to; does not convert it to a "canonical" type. Opens containers, properties etc and returns the ultimate contents.

Specified by:

getNode in interface Pointer

getRootNode

public java.lang.Object getRootNode()

Description copied from interface: Pointer

Returns the node this pointer is based on.

Specified by:

getRootNode in interface Pointer

getImmediateNode

public abstract java.lang.Object getImmediateNode()

Returns the object the pointer points to; does not convert it to a "canonical" type.

setValue

public abstract void setValue(java.lang.Object value)

Converts the value to the required type and changes the corresponding object to that value.

Specified by:

setValue in interface Pointer

compareChildNodePointers

public abstract int compareChildNodePointers(NodePointer pointer1,
                                             NodePointer pointer2)

Compares two child NodePointers and returns a positive number, zero or a positive number according to the order of the pointers.

testNode

public boolean testNode(NodeTest test)

Checks if this Pointer matches the supplied NodeTest.

equalStrings

private static boolean equalStrings(java.lang.String s1,
                                    java.lang.String s2)

createPath

public NodePointer createPath(JXPathContext context,
                              java.lang.Object value)

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

remove

public void remove()

Remove the node of the object graph this pointer points to.

createPath

public NodePointer createPath(JXPathContext context)

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.

createChild

public NodePointer createChild(JXPathContext context,
                               QName name,
                               int index,
                               java.lang.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. This method may have to expand the collection in order to assign the element.

createChild

public 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. It may have to expand the collection, then create an element object and return a new pointer describing the newly created element.

createAttribute

public NodePointer createAttribute(JXPathContext context,
                                   QName name)

Called to create a non-existing attribute

getLocale

public java.util.Locale getLocale()

If the Pointer has a parent, returns the parent's locale; otherwise returns the locale specified when this Pointer was created.

isLanguage

public boolean isLanguage(java.lang.String lang)

Returns true if the selected locale name starts with the specified prefix lang, case-insensitive.

childIterator

public NodeIterator childIterator(NodeTest test,
                                  boolean reverse,
                                  NodePointer startWith)

Returns a NodeIterator that iterates over all children or all children that match the given NodeTest, starting with the specified one.

attributeIterator

public NodeIterator attributeIterator(QName qname)

Returns a NodeIterator that iterates over all attributes of the current node matching the supplied node name (could have a wildcard). May return null if the object does not support the attributes.

namespaceIterator

public NodeIterator namespaceIterator()

Returns a NodeIterator that iterates over all namespaces of the value currently pointed at. May return null if the object does not support the namespaces.

namespacePointer

public NodePointer namespacePointer(java.lang.String namespace)

Returns a NodePointer for the specified namespace. Will return null if namespaces are not supported. Will return UNKNOWN_NAMESPACE if there is no such namespace.

getNamespaceURI

public java.lang.String getNamespaceURI(java.lang.String prefix)

Decodes a namespace prefix to the corresponding URI.

getNamespaceURI

public java.lang.String getNamespaceURI()

Returns the namespace URI associated with this Pointer.

isDefaultNamespace

protected boolean isDefaultNamespace(java.lang.String prefix)

Returns true if the supplied prefix represents the default namespace in the context of the current node.

getDefaultNamespaceURI

protected java.lang.String getDefaultNamespaceURI()

getPointerByID

public Pointer getPointerByID(JXPathContext context,
                              java.lang.String id)

Locates a node by ID.

getPointerByKey

public Pointer getPointerByKey(JXPathContext context,
                               java.lang.String key,
                               java.lang.String value)

Locates a node by key and value.

asPath

public java.lang.String asPath()

Returns an XPath that maps to this Pointer.

Specified by:

asPath in interface Pointer

clone

public java.lang.Object clone()

Description copied from interface: Pointer

Pointers are cloneable

Specified by:

clone in interface Pointer

toString

public java.lang.String toString()

compareTo

public int compareTo(java.lang.Object object)

Specified by:

compareTo in interface java.lang.Comparable

compareNodePointers

private int compareNodePointers(NodePointer p1,
                                int depth1,
                                NodePointer p2,
                                int depth2)

printPointerChain

public void printPointerChain()

Print internal structure of a pointer for debugging

printDeep

private static void printDeep(NodePointer pointer,
                              java.lang.String indent)