org.apache.xerces.dom
Class NodeImpl

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

Direct Known Subclasses:

CharacterDataImpl, NodeContainer, NotationImpl, ProcessingInstructionImpl

public abstract class NodeImpl

extends java.lang.Object

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

Node 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 NodeContainer 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.

Since:

PR-DOM-Level-1-19980818.

Version:

See Also:

Serialized Form

Field Summary

static short	ELEMENT_DEFINITION_NODE Element definition node type.
protected boolean	fInternalSetNodeValue flag to indicate whether setNodeValue was called by the client or from the DOM.
protected static int	MUTATION_AGGREGATE
protected static int	MUTATION_ALL
protected static int	MUTATION_LOCAL
protected static int	MUTATION_NONE The MUTATION_ values are parameters to the NON-DOM internalInsertBefore() and internalRemoveChild() operations, allowing us to control which MutationEvents are generated.
protected static boolean	MUTATIONEVENTS Compile-time flag.
protected java.lang.String	name Node name.
protected NodeImpl	nextSibling Next sibling.
protected DocumentImpl	ownerDocument Owner document.
protected NodeImpl	parentNode Parent node.
protected NodeImpl	previousSibling Previous sibling.
protected boolean	readOnly Read-only property.
protected boolean	syncData Synchronization of data needed.
protected java.lang.Object	userData NON-DOM FEATURE; see setUserData/getUserData.
protected java.lang.String	value Node value.

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(DocumentImpl ownerDocument, java.lang.String name, java.lang.String value) 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) Introduced in DOM Level 2.
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.
Node	cloneNode(boolean deep) Returns a duplicate of a given node.
boolean	dispatchEvent(Event event) Introduced in DOM Level 2.
protected void	finalize() NON-DOM INTERNAL: A finalizer has added to NodeImpl in order to correct the event-usage counts of any remaining listeners before discarding the Node.
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
java.lang.String	getNodeName() For many nodes, nodeName is derived from their nodeType mnemonic (lowercasified and preceeded by a '#' character).
abstract short	getNodeType() A short integer indicating what type of node this is.
java.lang.String	getNodeValue() nodeValue is a string representation of the data contained in this node.
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() Returns the user data associated to this node.
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.
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) Introduced in DOM Level 2.
Node	replaceChild(Node newChild, Node oldChild) Make newChild occupy the location that oldChild used to have.
void	setNodeValue(java.lang.String value) Any node which can have a nodeValue (@see getNodeValue) will also accept requests to set it to a string.
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.
boolean	supports(java.lang.String feature, java.lang.String version) Introduced in DOM Level 2.
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, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ELEMENT_DEFINITION_NODE

public static final short ELEMENT_DEFINITION_NODE

Element definition node type.

ownerDocument

protected DocumentImpl ownerDocument

Owner document.

parentNode

protected NodeImpl parentNode

Parent node.

previousSibling

protected NodeImpl previousSibling

Previous sibling.

nextSibling

protected NodeImpl nextSibling

Next sibling.

name

protected java.lang.String name

Node name.

value

protected java.lang.String value

Node value.

readOnly

protected boolean readOnly

Read-only property.

userData

protected java.lang.Object userData

NON-DOM FEATURE; see setUserData/getUserData.

fInternalSetNodeValue

protected boolean fInternalSetNodeValue

flag to indicate whether setNodeValue was called by the client or from the DOM.

syncData

protected transient boolean syncData

Synchronization of data needed.

MUTATIONEVENTS

protected static final boolean MUTATIONEVENTS

Compile-time flag. If false, disables our code for the DOM Level 2 Events module, perhaps allowing it to be optimized out to save bytecodes.

MUTATION_NONE

protected static final int MUTATION_NONE

The MUTATION_ values are parameters to the NON-DOM internalInsertBefore() and internalRemoveChild() operations, allowing us to control which MutationEvents are generated.

MUTATION_LOCAL

protected static final int MUTATION_LOCAL

MUTATION_AGGREGATE

protected static final int MUTATION_AGGREGATE

MUTATION_ALL

protected static final int MUTATION_ALL

Constructor Detail

NodeImpl

protected NodeImpl(DocumentImpl ownerDocument,
                   java.lang.String name,
                   java.lang.String value)

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 java.lang.String getNodeName()

For many nodes, nodeName is derived from their nodeType mnemonic (lowercasified and preceeded by a '#' character). Others return the "name of the data" -- tag name, attribute name, and so on.

Specified by:

getNodeName in interface Node

setNodeValue

public void setNodeValue(java.lang.String value)

Any node which can have a nodeValue (@see getNodeValue) will also accept requests to set it to a string. The exact response to this varies from node to node -- Attribute, for example, stores its values in its children and has to replace them with a new Text holding the replacement value.

For most types of Node, value is null and attempting to set it will throw DOMException(NO_MODIFICATION_ALLOWED_ERR). This will also be thrown if the node is read-only.

Specified by:

setNodeValue in interface Node

getNodeValue

public java.lang.String getNodeValue()

nodeValue is a string representation of the data contained in this node. Each subclass of Node defines what information is considered its value, or returns null if the query is not appropriate. Entity references should be expanded before being returned.

For most types of Node, value is null and may not be changed.

For Text, CDATASection, ProcessingInstruction, and Comment value is a string representing the contents of the node.

For Attribute, value is the string returned by the attribute's getValue method. This will be gathered from the Attribute's children.

Specified by:

getNodeValue in interface Node

Throws:

DOMException(DOMSTRING_SIZE_ERR) - when it would return more characters than fit in a DOMString variable on the implementation platform. (Will never arise in this implementation)

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, NodeContainer overrides this., NodeContainer

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, NodeContainer 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

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, NodeContainer overrides this.

Specified by:

hasChildNodes in interface Node

See Also:

NodeContainer

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, NodeContainer overrides this.

Specified by:

getFirstChild in interface Node

See Also:

NodeContainer

getLastChild

public Node getLastChild()

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

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

Specified by:

getLastChild in interface Node

See Also:

NodeContainer

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, NodeContainer 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:

NodeContainer

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, NodeContainer 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:

NodeContainer

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, NodeContainer 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:

NodeContainer

getLength

public int getLength()

NodeList method: Count the immediate children of this node

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

Specified by:

getLength in interface NodeList

Returns:

int

See Also:

NodeContainer

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, NodeContainer overrides this.

Specified by:

item in interface NodeList

Parameters:

Index - int

Returns:

org.w3c.dom.Node

See Also:

NodeContainer

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

supports

public boolean supports(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:

supports 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)

Introduced in DOM Level 2.

Register an event listener with this Node. A listener may be independently registered as both Capturing and Bubbling, but may only be registered once per role; redundant registrations are ignored.

Specified by:

addEventListener in interface EventTarget

Parameters:

type - Event name (NOT event group!) to listen for.

listener - Who gets called when event is dispatched

useCapture - True iff listener is registered on capturing phase rather than at-target or bubbling

removeEventListener

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

Introduced in DOM Level 2.

Deregister an event listener previously registered with this Node. A listener must be independently removed from the Capturing and Bubbling roles. Redundant removals (of listeners not currently registered for this role) are ignored.

Specified by:

removeEventListener in interface EventTarget

Parameters:

type - Event name (NOT event group!) to listen for.

listener - Who gets called when event is dispatched

useCapture - True iff listener is registered on capturing phase rather than at-target or bubbling

finalize

protected void finalize()
                 throws java.lang.Throwable

NON-DOM INTERNAL: A finalizer has added to NodeImpl in order to correct the event-usage counts of any remaining listeners before discarding the Node. This isn't absolutely required, and finalizers are of dubious reliability and have odd effects on some implementations of GC. But given the expense of event generation and distribution it seems a worthwhile safety net. RECONSIDER at some future point.

Overrides:

finalize in class java.lang.Object

dispatchEvent

public boolean dispatchEvent(Event event)

Introduced in DOM Level 2.

Distribution engine for DOM Level 2 Events.

Event propagation runs as follows:

1. Event is dispatched to a particular target node, which invokes this code. Note that the event's stopPropagation flag is cleared when dispatch begins; thereafter, if it has been set before processing of a node commences, we instead immediately advance to the DEFAULT phase.
2. The node's ancestors are established as destinations for events. For capture and bubble purposes, node ancestry is determined at the time dispatch starts. If an event handler alters the document tree, that does not change which nodes will be informed of the event.
3. CAPTURING_PHASE: Ancestors are scanned, root to target, for Capturing listeners. If found, they are invoked (see below).
4. AT_TARGET: Event is dispatched to NON-CAPTURING listeners on the target node. Note that capturing listeners on this node are _not_ invoked.
5. BUBBLING_PHASE: Ancestors are scanned, target to root, for non-capturing listeners.
6. Default processing: Some DOMs have default behaviors bound to specific nodes. If this DOM does, and if the event's preventDefault flag has not been set, we now return to the target node and process its default handler for this event, if any.

Note that (de)registration of handlers during processing of an event does not take effect during this phase of this event; they will not be called until the next time this node is visited by dispatchEvent.

If an event handler itself causes events to be dispatched, they are processed synchronously, before processing resumes on the event which triggered them. Please be aware that this may result in events arriving at listeners "out of order" relative to the actual sequence of requests.

Note that our implementation resets the event's stop/prevent flags when dispatch begins. I believe the DOM's intent is that event objects be redispatchable, though it isn't stated in those terms.

Specified by:

dispatchEvent in interface EventTarget

Parameters:

event - the event object to be dispatched to registered EventListeners

Returns:

true if the event's preventDefault() method was invoked by an EventListener; otherwise false.

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, NodeContainer 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:

NodeContainer

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.)

getUserData

public java.lang.Object getUserData()

Returns the user data associated to this node.

synchronizeData

protected void synchronizeData()

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

changed

protected void changed()

Denotes that this node has changed.

toString

public java.lang.String toString()

NON-DOM method for debugging convenience.

Overrides:

toString in class java.lang.Object