public abstract class

ParentNode

extends ChildNode
java.lang.Object
   ↳ org.apache.xerces.dom.NodeImpl
     ↳ org.apache.xerces.dom.ChildNode
       ↳ org.apache.xerces.dom.ParentNode
Known Direct Subclasses
Known Indirect Subclasses

Class Overview

ParentNode inherits from ChildNode and adds the capability of having child nodes. Not every node in the DOM can have children, so only nodes that can should inherit from this class and pay the price for it.

ParentNode, just like 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. On the other hand, subclasses may need to override this, in case of conflicting names. This is the case for the classes HTMLSelectElementImpl and HTMLFormElementImpl of the HTML DOM.

While we have a direct reference to the first child, the last child is stored as the previous sibling of the first child. First child nodes are marked as being so, and getNextSibling hides this fact.

Note: Not all parent nodes actually need to also be a child. At some point we used to have ParentNode inheriting from NodeImpl and another class called ChildAndParentNode that inherited from ChildNode. But due to the lack of multiple inheritance a lot of code had to be duplicated which led to a maintenance nightmare. At the same time only a few nodes (Document, DocumentFragment, Entity, and Attribute) cannot be a child so the gain in memory wasn't really worth it. The only type for which this would be the case is Attribute, but we deal with there in another special way, so this is not applicable.

This class doesn't directly support mutation events, however, it notifies the document when mutations are performed so that the document class do so.

WARNING: Some of the code here is partially duplicated in AttrImpl, be careful to keep these two classes in sync!@xerces.internal

Summary

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Inherited Constants
From class org.apache.xerces.dom.NodeImpl
From interface org.w3c.dom.Node
Fields
protected NodeListCache fNodeListCache NodeList cache
protected ChildNode firstChild First child.
protected CoreDocumentImpl ownerDocument Owner document.
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Inherited Fields
From class org.apache.xerces.dom.ChildNode
From class org.apache.xerces.dom.NodeImpl
Public Constructors
ParentNode()
Constructor for serialization.
Protected Constructors
ParentNode(CoreDocumentImpl ownerDocument)
No public constructor; only subclasses of ParentNode should be instantiated, and those normally via a Document's factory methods
Public Methods
Node cloneNode(boolean deep)
Returns a duplicate of a given node.
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 last child of this Node, or null if none.
int getLength()
NodeList method: Count the immediate children of this node
Document getOwnerDocument()
Find the Document that this Node belongs to (the document in whose context the Node was created).
String getTextContent()
This attribute returns the text content of this node and its descendants.
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 isEqualNode(Node arg)
DOM Level 3 WD- Experimental.
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()
Override default behavior to call normalize() on this Node's children.
Node removeChild(Node oldChild)
Remove a child from this Node.
Node replaceChild(Node newChild, Node oldChild)
Make newChild occupy the location that oldChild used to have.
void setReadOnly(boolean readOnly, boolean deep)
Override default behavior so that if deep is true, children are also toggled.
void setTextContent(String textContent)
This attribute returns the text content of this node and its descendants.
Protected Methods
final NodeList getChildNodesUnoptimized()
Create a NodeList to access children that is use by subclass elements that have methods named getLength() or item(int).
void setOwnerDocument(CoreDocumentImpl doc)
NON-DOM set the ownerDocument of this node and its children
void synchronizeChildren()
Override this method in subclass to hook in efficient internal data structure.
[Expand]
Inherited Methods
From class org.apache.xerces.dom.ChildNode
From class org.apache.xerces.dom.NodeImpl
From class java.lang.Object
From interface org.w3c.dom.Node
From interface org.w3c.dom.NodeList
From interface org.w3c.dom.events.EventTarget

Fields

protected NodeListCache fNodeListCache

NodeList cache

protected ChildNode firstChild

First child.

protected CoreDocumentImpl ownerDocument

Owner document.

Public Constructors

public ParentNode ()

Constructor for serialization.

Protected Constructors

protected ParentNode (CoreDocumentImpl ownerDocument)

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

Public Methods

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.

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.

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.

public Node getFirstChild ()

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

public Node getLastChild ()

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

public int getLength ()

NodeList method: Count the immediate children of this node

Returns
  • int

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.

public String getTextContent ()

This attribute returns the text content of this node and its descendants. When it is defined to be null, setting it has no effect. When set, any possible children this node may have are removed and replaced by a single Text node containing the string this attribute is set to. On getting, no serialization is performed, the returned string does not contain any markup. No whitespace normalization is performed, the returned string does not contain the element content whitespaces . Similarly, on setting, no parsing is performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node depending on its type, as defined below:

/** This attribute returns the text content of this node and its descendants. When it is defined to be null, setting it has no effect. When set, any possible children this node may have are removed and replaced by a single Text node containing the string this attribute is set to. On getting, no serialization is performed, the returned string does not contain any markup. No whitespace normalization is performed, the returned string does not contain the element content whitespaces . Similarly, on setting, no parsing is performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node depending on its type, as defined below:
Node type Content
Node type Content
ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, DOCUMENT_FRAGMENT_NODE concatenation of the textContent attribute value of every child node, excluding COMMENT_NODE and PROCESSING_INSTRUCTION_NODE nodes
ATTRIBUTE_NODE, TEXT_NODE, CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE nodeValue
DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE null

Throws
DOMException

public boolean hasChildNodes ()

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

public Node insertBefore (Node newChild, Node refChild)

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

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().
Returns
  • newChild, in its new state (relocated, or emptied in the case of DocumentNode.)
Throws
if newChild is of a type that shouldn't be a child of this node, or if newChild is an ancestor of this node.
if newChild has a different owner document than we do.
if refChild is not a child of this node.
if this node is read-only.
DOMException

public boolean isEqualNode (Node arg)

DOM Level 3 WD- Experimental. Override inherited behavior from NodeImpl to support deep equal.

Parameters
arg The node to compare equality with.
Returns
  • If the nodes, and possibly subtrees are equal, true otherwise false.

public Node item (int index)

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

Parameters
index int
Returns
  • org.w3c.dom.Node

public void normalize ()

Override default behavior to call normalize() on this Node's children. It is up to implementors or Node to override normalize() to take action.

public Node removeChild (Node oldChild)

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

Returns
  • oldChild, in its new state (removed).
Throws
if oldChild is not a child of this node.
if this node is read-only.
DOMException

public Node replaceChild (Node newChild, Node oldChild)

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.

Returns
  • oldChild, in its new state (removed).
Throws
if newChild is of a type that shouldn't be a child of this node, or if newChild is one of our ancestors.
if newChild has a different owner document than we do.
if oldChild is not a child of this node.
if this node is read-only.
DOMException

public void setReadOnly (boolean readOnly, boolean deep)

Override default behavior so that if deep is true, children are also toggled.

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
  • Node

    Note: this will not change the state of an EntityReference or its children, which are always read-only.

public void setTextContent (String textContent)

This attribute returns the text content of this node and its descendants. When it is defined to be null, setting it has no effect. When set, any possible children this node may have are removed and replaced by a single Text node containing the string this attribute is set to. On getting, no serialization is performed, the returned string does not contain any markup. No whitespace normalization is performed, the returned string does not contain the element content whitespaces . Similarly, on setting, no parsing is performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node depending on its type, as defined below:

Node type Content
ELEMENT_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, DOCUMENT_FRAGMENT_NODE concatenation of the textContent attribute value of every child node, excluding COMMENT_NODE and PROCESSING_INSTRUCTION_NODE nodes
ATTRIBUTE_NODE, TEXT_NODE, CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE nodeValue
DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE null

Throws
DOMException

Protected Methods

protected final NodeList getChildNodesUnoptimized ()

Create a NodeList to access children that is use by subclass elements that have methods named getLength() or item(int). ChildAndParentNode optimizes getChildNodes() by implementing NodeList itself. However if a subclass Element implements methods with the same name as the NodeList methods, they will override the actually methods in this class.

To use this method, the subclass should implement getChildNodes() and have it call this method. The resulting NodeList instance maybe shared and cached in a transient field, but the cached value must be cleared if the node is cloned.

protected void setOwnerDocument (CoreDocumentImpl doc)

NON-DOM set the ownerDocument of this node and its children

protected void synchronizeChildren ()

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