Class ParentNode

All Implemented Interfaces:
Serializable, Cloneable, EventTarget, Node, NodeList
Direct Known Subclasses:
CoreDocumentImpl, DocumentFragmentImpl, DocumentTypeImpl, ElementDefinitionImpl, ElementImpl, EntityImpl, EntityReferenceImpl

public abstract class ParentNode extends ChildNode
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!

INTERNAL:

Usage of this class is not supported. It may be altered or removed at any time.
Version:
$Id: ParentNode.java 1399511 2012-10-18 04:10:42Z mrglavas $
Author:
Arnaud Le Hors, IBM, Joe Kesselman, IBM, Andy Clark, IBM
See Also:
  • Field Details

    • ownerDocument

      protected CoreDocumentImpl ownerDocument
      Owner document.
    • firstChild

      protected ChildNode firstChild
      First child.
    • fNodeListCache

      protected transient org.apache.xerces.dom.NodeListCache fNodeListCache
      NodeList cache
  • Constructor Details

    • ParentNode

      protected ParentNode(CoreDocumentImpl ownerDocument)
      No public constructor; only subclasses of ParentNode should be instantiated, and those normally via a Document's factory methods
    • ParentNode

      public ParentNode()
      Constructor for serialization.
  • Method Details

    • 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.

      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.

      Specified by:
      cloneNode in interface Node
      Overrides:
      cloneNode in class ChildNode
      See Also:
    • 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
      Overrides:
      getOwnerDocument in class NodeImpl
    • setOwnerDocument

      protected void setOwnerDocument(CoreDocumentImpl doc)
      NON-DOM set the ownerDocument of this node and its children
      Overrides:
      setOwnerDocument in class NodeImpl
    • hasChildNodes

      public boolean hasChildNodes()
      Test whether this node has any children. Convenience shorthand for (Node.getFirstChild()!=null)
      Specified by:
      hasChildNodes in interface Node
      Overrides:
      hasChildNodes in class NodeImpl
      See Also:
    • 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
      Overrides:
      getChildNodes in class NodeImpl
    • getFirstChild

      public Node getFirstChild()
      The first child of this Node, or null if none.
      Specified by:
      getFirstChild in interface Node
      Overrides:
      getFirstChild in class NodeImpl
      See Also:
    • getLastChild

      public Node getLastChild()
      The last child of this Node, or null if none.
      Specified by:
      getLastChild in interface Node
      Overrides:
      getLastChild in class NodeImpl
      See Also:
    • 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.
      Specified by:
      insertBefore in interface Node
      Overrides:
      insertBefore in class NodeImpl
      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:
      DOMException
      See Also:
    • 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.
      Specified by:
      removeChild in interface Node
      Overrides:
      removeChild in class NodeImpl
      Returns:
      oldChild, in its new state (removed).
      Throws:
      DOMException
      See Also:
    • 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.
      Specified by:
      replaceChild in interface Node
      Overrides:
      replaceChild in class NodeImpl
      Returns:
      oldChild, in its new state (removed).
      Throws:
      DOMException
      See Also:
    • getTextContent

      public String getTextContent() throws DOMException
      Description copied from class: NodeImpl
      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
      Specified by:
      getTextContent in interface Node
      Overrides:
      getTextContent in class NodeImpl
      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.
    • setTextContent

      public void setTextContent(String textContent) throws DOMException
      Description copied from class: NodeImpl
      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
      Specified by:
      setTextContent in interface Node
      Overrides:
      setTextContent in class NodeImpl
      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.
    • getLength

      public int getLength()
      NodeList method: Count the immediate children of this node
      Specified by:
      getLength in interface NodeList
      Overrides:
      getLength in class NodeImpl
      Returns:
      int
      See Also:
    • 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.
      Specified by:
      item in interface NodeList
      Overrides:
      item in class NodeImpl
      Parameters:
      index - int
      Returns:
      org.w3c.dom.Node
      See Also:
    • getChildNodesUnoptimized

      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.

    • normalize

      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.
      Specified by:
      normalize in interface Node
      Overrides:
      normalize in class NodeImpl
    • isEqualNode

      public boolean isEqualNode(Node arg)
      DOM Level 3 WD- Experimental. Override inherited behavior from NodeImpl to support deep equal.
      Specified by:
      isEqualNode in interface Node
      Overrides:
      isEqualNode in class NodeImpl
      Parameters:
      arg - The node to compare equality with.
      Returns:
      If the nodes, and possibly subtrees are equal, true otherwise false.
    • setReadOnly

      public void setReadOnly(boolean readOnly, boolean deep)
      Override default behavior so that if deep is true, children are also toggled.
      Overrides:
      setReadOnly in class NodeImpl
      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:
    • synchronizeChildren

      protected void synchronizeChildren()
      Override this method in subclass to hook in efficient internal data structure.