org.apache.xerces.dom
Class NodeImpl

java.lang.Object
  |
  +--org.apache.xerces.dom.NodeImpl

Direct Known Subclasses:

AttrImpl, ChildNode, NotationImpl

public abstract class NodeImpl

extends java.lang.Object

implements Node, NodeList, EventTarget, java.lang.Cloneable, java.io.Serializable

NodeImpl provides the basic structure of a DOM tree. It is never used directly, but instead is subclassed to add type and data information, and additional methods, appropriate to each node of the tree. Only its subclasses should be instantiated -- and those, with the exception of Document itself, only through a specific Document's factory methods.

The Node interface provides shared behaviors such as siblings and children, both for consistancy and so that the most common tree operations may be performed without constantly having to downcast to specific node types. When there is no obvious mapping for one of these queries, it will respond with null. Note that the default behavior is that children are forbidden. To permit them, the subclass ParentNode overrides several methods.

NodeImpl also implements NodeList, so it can return itself in response to the getChildNodes() query. This eliminiates the need for a separate ChildNodeList object. Note that this is an IMPLEMENTATION DETAIL; applications should _never_ assume that this identity exists.

All nodes in a single document must originate in that document. (Note that this is much tighter than "must be same implementation") Nodes are all aware of their ownerDocument, and attempts to mismatch will throw WRONG_DOCUMENT_ERR.

However, to save memory not all nodes always have a direct reference to their ownerDocument. When a node is owned by another node it relies on its owner to store its ownerDocument. Parent nodes always store it though, so there is never more than one level of indirection. And when a node doesn't have an owner, ownerNode refers to its ownerDocument.

This class doesn't directly support mutation events, however, it still implements the EventTarget interface and forward all related calls to the document so that the document class do so.

Since:

PR-DOM-Level-1-19980818.

Version:

Author:

Arnaud Le Hors, IBM, Joe Kesselman, IBM

See Also:

Serialized Form

Field Summary

static short	ELEMENT_DEFINITION_NODE Element definition node type.
protected static short	FIRSTCHILD
protected short	flags
protected static short	HASSTRING
protected static short	IGNORABLEWS
protected static short	OWNED
protected NodeImpl	ownerNode
protected static short	READONLY
protected static short	SPECIFIED
protected static short	SYNCCHILDREN
protected static short	SYNCDATA
protected static short	UNNORMALIZED

Fields inherited from interface org.w3c.dom.Node

ATTRIBUTE_NODE, CDATA_SECTION_NODE, COMMENT_NODE, DOCUMENT_FRAGMENT_NODE, DOCUMENT_NODE, DOCUMENT_TYPE_NODE, ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, NOTATION_NODE, PROCESSING_INSTRUCTION_NODE, TEXT_NODE

Constructor Summary

	NodeImpl() Constructor for serialization.
protected	NodeImpl(CoreDocumentImpl ownerDocument) No public constructor; only subclasses of Node should be instantiated, and those normally via a Document's factory methods

Method Summary

void	addEventListener(java.lang.String type, EventListener listener, boolean useCapture) This method allows the registration of event listeners on the event target.
Node	appendChild(Node newChild) Adds a child node to the end of the list of children for this node.
protected void	changed() Denotes that this node has changed.
protected int	changes() Returns the number of changes to this node.
Node	cloneNode(boolean deep) Returns a duplicate of a given node.
boolean	dispatchEvent(Event event) This method allows the dispatch of events into the implementations event model.
NamedNodeMap	getAttributes() Return the collection of attributes associated with this node, or null if none.
NodeList	getChildNodes() Obtain a NodeList enumerating all children of this node.
Node	getFirstChild() The first child of this Node, or null if none.
Node	getLastChild() The first child of this Node, or null if none.
int	getLength() NodeList method: Count the immediate children of this node
java.lang.String	getLocalName() Introduced in DOM Level 2.
java.lang.String	getNamespaceURI() Introduced in DOM Level 2.
Node	getNextSibling() The next child of this node's parent, or null if none
abstract java.lang.String	getNodeName() the name of this node.
abstract short	getNodeType() A short integer indicating what type of node this is.
java.lang.String	getNodeValue() Returns the node value.
Document	getOwnerDocument() Find the Document that this Node belongs to (the document in whose context the Node was created).
Node	getParentNode() Obtain the DOM-tree parent of this node, or null if it is not currently active in the DOM tree (perhaps because it has just been created or removed).
java.lang.String	getPrefix() Introduced in DOM Level 2.
Node	getPreviousSibling() The previous child of this node's parent, or null if none
boolean	getReadOnly() NON-DOM: Returns true if this node is read-only.
java.lang.Object	getUserData() NON-DOM: Returns the user data associated to this node.
boolean	hasAttributes() Returns whether this node (if it is an element) has any attributes.
boolean	hasChildNodes() Test whether this node has any children.
Node	insertBefore(Node newChild, Node refChild) Move one or more node(s) to our list of children.
boolean	isSupported(java.lang.String feature, java.lang.String version) Introduced in DOM Level 2.
Node	item(int index) NodeList method: Return the Nth immediate child of this node, or null if the index is out of bounds.
void	normalize() Puts all Text nodes in the full depth of the sub-tree underneath this Node, including attribute nodes, into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separates Text nodes, i.e., there are no adjacent Text nodes.
Node	removeChild(Node oldChild) Remove a child from this Node.
void	removeEventListener(java.lang.String type, EventListener listener, boolean useCapture) This method allows the removal of event listeners from the event target.
Node	replaceChild(Node newChild, Node oldChild) Make newChild occupy the location that oldChild used to have.
void	setNodeValue(java.lang.String x) Sets the node value.
void	setPrefix(java.lang.String prefix) Introduced in DOM Level 2.
void	setReadOnly(boolean readOnly, boolean deep) NON-DOM: PR-DOM-Level-1-19980818 mentions readonly nodes in conjunction with Entities, but provides no API to support this.
void	setUserData(java.lang.Object data) NON-DOM: As an alternative to subclassing the DOM, this implementation has been extended with the ability to attach an object to each node.
protected void	synchronizeData() Override this method in subclass to hook in efficient internal data structure.
java.lang.String	toString() NON-DOM method for debugging convenience.

Methods inherited from class java.lang.Object

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

Field Detail

ELEMENT_DEFINITION_NODE

public static final short ELEMENT_DEFINITION_NODE

Element definition node type.

ownerNode

protected NodeImpl ownerNode

flags

protected short flags

READONLY

protected static final short READONLY

SYNCDATA

protected static final short SYNCDATA

SYNCCHILDREN

protected static final short SYNCCHILDREN

OWNED

protected static final short OWNED

FIRSTCHILD

protected static final short FIRSTCHILD

SPECIFIED

protected static final short SPECIFIED

IGNORABLEWS

protected static final short IGNORABLEWS

HASSTRING

protected static final short HASSTRING

UNNORMALIZED

protected static final short UNNORMALIZED

Constructor Detail

NodeImpl

protected NodeImpl(CoreDocumentImpl ownerDocument)

No public constructor; only subclasses of Node should be instantiated, and those normally via a Document's factory methods

Every Node knows what Document it belongs to.

NodeImpl

public NodeImpl()

Constructor for serialization.

Method Detail

getNodeType

public abstract short getNodeType()

A short integer indicating what type of node this is. The named constants for this value are defined in the org.w3c.dom.Node interface.

Specified by:

getNodeType in interface Node

getNodeName

public abstract java.lang.String getNodeName()

the name of this node.

Specified by:

getNodeName in interface Node

getNodeValue

public java.lang.String getNodeValue()

Returns the node value.

Specified by:

getNodeValue in interface Node

Tags copied from interface: Node

Throws:

DOMException - NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.

DOMException - DOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in a DOMString variable on the implementation platform.

setNodeValue

public void setNodeValue(java.lang.String x)
                  throws DOMException

Sets the node value.

Specified by:

setNodeValue in interface Node

Throws:

DOMException(NO_MODIFICATION_ALLOWED_ERR) -

appendChild

public Node appendChild(Node newChild)
                 throws DOMException

Adds a child node to the end of the list of children for this node. Convenience shorthand for insertBefore(newChild,null).

Specified by:

appendChild in interface Node

Throws:

DOMException(HIERARCHY_REQUEST_ERR) - if newChild is of a type that shouldn't be a child of this node.

DOMException(WRONG_DOCUMENT_ERR) - if newChild has a different owner document than we do.

DOMException(NO_MODIFICATION_ALLOWED_ERR) - if this node is read-only.

See Also:

By default we do not accept any children, ParentNode overrides this., ParentNode

cloneNode

public Node cloneNode(boolean deep)

Returns a duplicate of a given node. You can consider this a generic "copy constructor" for nodes. The newly returned object should be completely independent of the source object's subtree, so changes in one after the clone has been made will not affect the other.

Note: since we never have any children deep is meaningless here, ParentNode overrides this behavior.

Specified by:

cloneNode in interface Node

See Also:

Example: Cloning a Text node will copy both the node and the text it contains.

Example: Cloning something that has children -- Element or Attr, for example -- will _not_ clone those children unless a "deep clone" has been requested. A shallow clone of an Attr node will yield an empty Attr of the same name.

NOTE: Clones will always be read/write, even if the node being cloned is read-only, to permit applications using only the DOM API to obtain editable copies of locked portions of the tree.

getOwnerDocument

public Document getOwnerDocument()

Find the Document that this Node belongs to (the document in whose context the Node was created). The Node may or may not currently be part of that Document's actual contents.

Specified by:

getOwnerDocument in interface Node

getParentNode

public Node getParentNode()

Obtain the DOM-tree parent of this node, or null if it is not currently active in the DOM tree (perhaps because it has just been created or removed). Note that Document, DocumentFragment, and Attribute will never have parents.

Specified by:

getParentNode in interface Node

getNextSibling

public Node getNextSibling()

The next child of this node's parent, or null if none

Specified by:

getNextSibling in interface Node

getPreviousSibling

public Node getPreviousSibling()

The previous child of this node's parent, or null if none

Specified by:

getPreviousSibling in interface Node

getAttributes

public NamedNodeMap getAttributes()

Return the collection of attributes associated with this node, or null if none. At this writing, Element is the only type of node which will ever have attributes.

Specified by:

getAttributes in interface Node

See Also:

ElementImpl

hasAttributes

public boolean hasAttributes()

Returns whether this node (if it is an element) has any attributes.

Specified by:

hasAttributes in interface Node

Returns:

true if this node has any attributes, false otherwise.

Since:

DOM Level 2

See Also:

ElementImpl

hasChildNodes

public boolean hasChildNodes()

Test whether this node has any children. Convenience shorthand for (Node.getFirstChild()!=null)

By default we do not have any children, ParentNode overrides this.

Specified by:

hasChildNodes in interface Node

See Also:

ParentNode

getChildNodes

public NodeList getChildNodes()

Obtain a NodeList enumerating all children of this node. If there are none, an (initially) empty NodeList is returned.

NodeLists are "live"; as children are added/removed the NodeList will immediately reflect those changes. Also, the NodeList refers to the actual nodes, so changes to those nodes made via the DOM tree will be reflected in the NodeList and vice versa.

In this implementation, Nodes implement the NodeList interface and provide their own getChildNodes() support. Other DOMs may solve this differently.

Specified by:

getChildNodes in interface Node

getFirstChild

public Node getFirstChild()

The first child of this Node, or null if none.

By default we do not have any children, ParentNode overrides this.

Specified by:

getFirstChild in interface Node

See Also:

ParentNode

getLastChild

public Node getLastChild()

The first child of this Node, or null if none.

By default we do not have any children, ParentNode overrides this.

Specified by:

getLastChild in interface Node

See Also:

ParentNode

insertBefore

public Node insertBefore(Node newChild,
                         Node refChild)
                  throws DOMException

Move one or more node(s) to our list of children. Note that this implicitly removes them from their previous parent.

By default we do not accept any children, ParentNode overrides this.

Specified by:

insertBefore in interface Node

Parameters:

newChild - The Node to be moved to our subtree. As a convenience feature, inserting a DocumentNode will instead insert all its children.

refChild - Current child which newChild should be placed immediately before. If refChild is null, the insertion occurs after all existing Nodes, like appendChild().

Throws:

DOMException(HIERARCHY_REQUEST_ERR) - if newChild is of a type that shouldn't be a child of this node, or if newChild is an ancestor of this node.

DOMException(WRONG_DOCUMENT_ERR) - if newChild has a different owner document than we do.

DOMException(NOT_FOUND_ERR) - if refChild is not a child of this node.

DOMException(NO_MODIFICATION_ALLOWED_ERR) - if this node is read-only.

See Also:

ParentNode

removeChild

public Node removeChild(Node oldChild)
                 throws DOMException

Remove a child from this Node. The removed child's subtree remains intact so it may be re-inserted elsewhere.

By default we do not have any children, ParentNode overrides this.

Specified by:

removeChild in interface Node

Returns:

oldChild, in its new state (removed).

Throws:

DOMException(NOT_FOUND_ERR) - if oldChild is not a child of this node.

DOMException(NO_MODIFICATION_ALLOWED_ERR) - if this node is read-only.

See Also:

ParentNode

replaceChild

public Node replaceChild(Node newChild,
                         Node oldChild)
                  throws DOMException

Make newChild occupy the location that oldChild used to have. Note that newChild will first be removed from its previous parent, if any. Equivalent to inserting newChild before oldChild, then removing oldChild.

By default we do not have any children, ParentNode overrides this.

Specified by:

replaceChild in interface Node

Throws:

DOMException(HIERARCHY_REQUEST_ERR) - if newChild is of a type that shouldn't be a child of this node, or if newChild is one of our ancestors.

DOMException(WRONG_DOCUMENT_ERR) - if newChild has a different owner document than we do.

DOMException(NOT_FOUND_ERR) - if oldChild is not a child of this node.

DOMException(NO_MODIFICATION_ALLOWED_ERR) - if this node is read-only.

See Also:

ParentNode

getLength

public int getLength()

NodeList method: Count the immediate children of this node

By default we do not have any children, ParentNode overrides this.

Specified by:

getLength in interface NodeList

Returns:

int

See Also:

ParentNode

item

public Node item(int index)

NodeList method: Return the Nth immediate child of this node, or null if the index is out of bounds.

By default we do not have any children, ParentNode overrides this.

Specified by:

item in interface NodeList

Parameters:

Index - int

Returns:

org.w3c.dom.Node

See Also:

ParentNode

normalize

public void normalize()

Puts all Text nodes in the full depth of the sub-tree underneath this Node, including attribute nodes, into a "normal" form where only markup (e.g., tags, comments, processing instructions, CDATA sections, and entity references) separates Text nodes, i.e., there are no adjacent Text nodes. This can be used to ensure that the DOM view of a document is the same as if it were saved and re-loaded, and is useful when operations (such as XPointer lookups) that depend on a particular document tree structure are to be used.In cases where the document contains CDATASections, the normalize operation alone may not be sufficient, since XPointers do not differentiate between Text nodes and CDATASection nodes.

Note that this implementation simply calls normalize() on this Node's children. It is up to implementors or Node to override normalize() to take action.

Specified by:

normalize in interface Node

isSupported

public boolean isSupported(java.lang.String feature,
                           java.lang.String version)

Introduced in DOM Level 2.

Tests whether the DOM implementation implements a specific feature and that feature is supported by this node.

Specified by:

isSupported in interface Node

Parameters:

feature - The package name of the feature to test. This is the same name as what can be passed to the method hasFeature on DOMImplementation.

version - This is the version number of the package name to test. In Level 2, version 1, this is the string "2.0". If the version is not specified, supporting any version of the feature will cause the method to return true.

Returns:

boolean Returns true if this node defines a subtree within which the specified feature is supported, false otherwise.

Since:

WD-DOM-Level-2-19990923

getNamespaceURI

public java.lang.String getNamespaceURI()

Introduced in DOM Level 2.

The namespace URI of this node, or null if it is unspecified. When this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE, this is always null and setting it has no effect.

This is not a computed value that is the result of a namespace lookup based on an examination of the namespace declarations in scope. It is merely the namespace URI given at creation time.

For nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is null.

Specified by:

getNamespaceURI in interface Node

Since:

WD-DOM-Level-2-19990923

See Also:

AttrNSImpl, ElementNSImpl

getPrefix

public java.lang.String getPrefix()

Introduced in DOM Level 2.

The namespace prefix of this node, or null if it is unspecified. When this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this is always null and setting it has no effect.

For nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is null.

Specified by:

getPrefix in interface Node

Since:

WD-DOM-Level-2-19990923

See Also:

AttrNSImpl, ElementNSImpl

setPrefix

public void setPrefix(java.lang.String prefix)
               throws DOMException

Introduced in DOM Level 2.

The namespace prefix of this node, or null if it is unspecified. When this node is of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this is always null and setting it has no effect.

For nodes created with a DOM Level 1 method, such as createElement from the Document interface, this is null.

Note that setting this attribute changes the nodeName attribute, which holds the qualified name, as well as the tagName and name attributes of the Element and Attr interfaces, when applicable.

Specified by:

setPrefix in interface Node

Throws:

INVALID_CHARACTER_ERR - Raised if the specified prefix contains an invalid character.

Since:

WD-DOM-Level-2-19990923

See Also:

AttrNSImpl, ElementNSImpl

getLocalName

public java.lang.String getLocalName()

Introduced in DOM Level 2.

Returns the local part of the qualified name of this node. For nodes created with a DOM Level 1 method, such as createElement from the Document interface, and for nodes of any type other than ELEMENT_NODE and ATTRIBUTE_NODE this is the same as the nodeName attribute.

Specified by:

getLocalName in interface Node

Since:

WD-DOM-Level-2-19990923

See Also:

AttrNSImpl, ElementNSImpl

addEventListener

public void addEventListener(java.lang.String type,
                             EventListener listener,
                             boolean useCapture)

Description copied from interface: EventTarget

This method allows the registration of event listeners on the event target. If an EventListener is added to an EventTarget while it is processing an event, it will not be triggered by the current actions but may be triggered during a later stage of event flow, such as the bubbling phase.
If multiple identical EventListeners are registered on the same EventTarget with the same parameters the duplicate instances are discarded. They do not cause the EventListener to be called twice and since they are discarded they do not need to be removed with the removeEventListener method.

Specified by:

addEventListener in interface EventTarget

Tags copied from interface: EventTarget

Parameters:

typeThe - event type for which the user is registering

listenerThe - listener parameter takes an interface implemented by the user which contains the methods to be called when the event occurs.

useCaptureIf - true, useCapture indicates that the user wishes to initiate capture. After initiating capture, all events of the specified type will be dispatched to the registered EventListener before being dispatched to any EventTargets beneath them in the tree. Events which are bubbling upward through the tree will not trigger an EventListener designated to use capture.

removeEventListener

public void removeEventListener(java.lang.String type,
                                EventListener listener,
                                boolean useCapture)

Description copied from interface: EventTarget

This method allows the removal of event listeners from the event target. If an EventListener is removed from an EventTarget while it is processing an event, it will not be triggered by the current actions. EventListeners can never be invoked after being removed.
Calling removeEventListener with arguments which do not identify any currently registered EventListener on the EventTarget has no effect.

Specified by:

removeEventListener in interface EventTarget

Tags copied from interface: EventTarget

Parameters:

typeSpecifies - the event type of the EventListener being removed.

listenerThe - EventListener parameter indicates the EventListener to be removed.

useCaptureSpecifies - whether the EventListener being removed was registered as a capturing listener or not. If a listener was registered twice, one with capture and one without, each must be removed separately. Removal of a capturing listener does not affect a non-capturing version of the same listener, and vice versa.

dispatchEvent

public boolean dispatchEvent(Event event)

Description copied from interface: EventTarget

This method allows the dispatch of events into the implementations event model. Events dispatched in this manner will have the same capturing and bubbling behavior as events dispatched directly by the implementation. The target of the event is the EventTarget on which dispatchEvent is called.

Specified by:

dispatchEvent in interface EventTarget

Tags copied from interface: EventTarget

Parameters:

evtSpecifies - the event type, behavior, and contextual information to be used in processing the event.

Returns:

The return value of dispatchEvent indicates whether any of the listeners which handled the event called preventDefault. If preventDefault was called the value is false, else the value is true.

Throws:

EventException - UNSPECIFIED_EVENT_TYPE_ERR: Raised if the Event's type was not specified by initializing the event before dispatchEvent was called. Specification of the Event's type as null or an empty string will also trigger this exception.

setReadOnly

public void setReadOnly(boolean readOnly,
                        boolean deep)

NON-DOM: PR-DOM-Level-1-19980818 mentions readonly nodes in conjunction with Entities, but provides no API to support this.

Most DOM users should not touch this method. Its anticpated use is during construction of EntityRefernces, where it will be used to lock the contents replicated from Entity so they can't be casually altered. It _could_ be published as a DOM extension, if desired.

Note: since we never have any children deep is meaningless here, ParentNode overrides this behavior.

Parameters:

readOnly - True or false as desired.

deep - If true, children are also toggled. Note that this will not change the state of an EntityReference or its children, which are always read-only.

See Also:

ParentNode

getReadOnly

public boolean getReadOnly()

NON-DOM: Returns true if this node is read-only. This is a shallow check.

setUserData

public void setUserData(java.lang.Object data)

NON-DOM: As an alternative to subclassing the DOM, this implementation has been extended with the ability to attach an object to each node. (If you need multiple objects, you can attach a collection such as a vector or hashtable, then attach your application information to that.)

Important Note: You are responsible for removing references to your data on nodes that are no longer used. Failure to do so will prevent the nodes, your data is attached to, to be garbage collected until the whole document is.

Parameters:

data - the object to store or null to remove any existing reference

getUserData

public java.lang.Object getUserData()

NON-DOM: Returns the user data associated to this node.

changed

protected void changed()

Denotes that this node has changed.

changes

protected int changes()

Returns the number of changes to this node.

synchronizeData

protected void synchronizeData()

Override this method in subclass to hook in efficient internal data structure.

toString

public java.lang.String toString()

NON-DOM method for debugging convenience.

Overrides:

toString in class java.lang.Object