Lecture Outline

• We shall study the Document Object Model Core module of the Document Object Model (DOM) Level 2 Core Specification, Version 1.0, which is a W3C Recommendation published on November 13, 2000.
  Link: http://www.w3.org/TR/DOM-Level-2-Core/
• We shall study the example in Chapter 19: Document Object Model (DOM), in the book XML in a Nutshell, 3rd Edition, by Elliotte Rusty Harold.
  Link: http://www.cafeconleche.org/books/xian3/examples/19/.
• The Java code in the example is to be used with the example files from Chapter 21: XML 1.0 Reference of the same books.
  Link: http://www.cafeconleche.org/books/xian3/examples/21/.

DOM

• The DOM presents documents as a hierarchy of Node objects that also implement other, more specialized interfaces. Some types of nodes may have child nodes of various types, and others are leaf nodes that cannot have anything below them in the document structure.
• The DOM also specifies a NodeList interface to handle ordered lists of Nodes, such as the children of a Node, or the elements returned by the getElementsByTagName method of the Element interface, and also a NamedNodeMap interface to handle unordered sets of nodes referenced by their name attribute, such as the attributes of an Element.
• NodeList and NamedNodeMap objects in the DOM are live; that is, changes to the underlying document structure are reflected in all relevant NodeList and NamedNodeMap objects.

Node Types

The node types, and which node types they may have as children, are as follows:

• Document — Element (maximum of one), ProcessingInstruction, Comment, DocumentType (maximum of one)
• DocumentFragment — Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
• DocumentType — no children
• EntityReference — Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
• Element — Element, Text, Comment, ProcessingInstruction, CDATASection, EntityReference
• Attr — Text, EntityReference
• ProcessingInstruction — no children
• Comment — no children
• Text — no children
• CDATASection — no children
• Entity — Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
• Notation — no children

Interface for Node

The Node interface is the primary datatype for the entire Document Object Model. It represents a single node in the document tree. While all objects implementing the Node interface expose methods for dealing with children, not all objects implementing the Node interface may have children.

The attributes nodeName, nodeValue and attributes are included as a mechanism to get at node information without casting down to the specific derived interface. In cases where there is no obvious mapping of these attributes for a specific nodeType (e.g., nodeValue for an Element or attributes for a Comment), this returns null. Note that the specialized interfaces may contain additional and more convenient mechanisms to get and set the relevant information.

interface Node {

  // NodeType
  const unsigned short      ELEMENT_NODE                   = 1;
  const unsigned short      ATTRIBUTE_NODE                 = 2;
  const unsigned short      TEXT_NODE                      = 3;
  const unsigned short      CDATA_SECTION_NODE             = 4;
  const unsigned short      ENTITY_REFERENCE_NODE          = 5;
  const unsigned short      ENTITY_NODE                    = 6;
  const unsigned short      PROCESSING_INSTRUCTION_NODE    = 7;
  const unsigned short      COMMENT_NODE                   = 8;
  const unsigned short      DOCUMENT_NODE                  = 9;
  const unsigned short      DOCUMENT_TYPE_NODE             = 10;
  const unsigned short      DOCUMENT_FRAGMENT_NODE         = 11;
  const unsigned short      NOTATION_NODE                  = 12;

  readonly attribute DOMString        nodeName;
           attribute DOMString        nodeValue;
                                        // raises(DOMException) on setting
                                        // raises(DOMException) on retrieval

  readonly attribute unsigned short   nodeType;
  readonly attribute Node             parentNode;
  readonly attribute NodeList         childNodes;
  readonly attribute Node             firstChild;
  readonly attribute Node             lastChild;
  readonly attribute Node             previousSibling;
  readonly attribute Node             nextSibling;
  readonly attribute NamedNodeMap     attributes;
  // Modified in DOM Level 2:
  readonly attribute Document         ownerDocument;
  Node               insertBefore(in Node newChild, 
                                  in Node refChild)
                                        raises(DOMException);
  Node               replaceChild(in Node newChild, 
                                  in Node oldChild)
                                        raises(DOMException);
  Node               removeChild(in Node oldChild)
                                        raises(DOMException);
  Node               appendChild(in Node newChild)
                                        raises(DOMException);
  boolean            hasChildNodes();
  Node               cloneNode(in boolean deep);
  // Modified in DOM Level 2:
  void               normalize();
  // Introduced in DOM Level 2:
  boolean            isSupported(in DOMString feature, 
                                 in DOMString version);
  // Introduced in DOM Level 2:
  readonly attribute DOMString        namespaceURI;
  // Introduced in DOM Level 2:
           attribute DOMString        prefix;
                                        // raises(DOMException) on setting

  // Introduced in DOM Level 2:
  readonly attribute DOMString        localName;
  // Introduced in DOM Level 2:
  boolean            hasAttributes();
};

Interface for ELement

The Element interface represents an element in an HTML or XML document. Elements may have attributes associated with them; since the Element interface inherits from Node, the generic Node interface attribute attributes may be used to retrieve the set of all attributes for an element.

interface Element : Node {
  readonly attribute DOMString        tagName;
  DOMString          getAttribute(in DOMString name);
  void               setAttribute(in DOMString name, 
                                  in DOMString value)
                                        raises(DOMException);
  void               removeAttribute(in DOMString name)
                                        raises(DOMException);
  Attr               getAttributeNode(in DOMString name);
  Attr               setAttributeNode(in Attr newAttr)
                                        raises(DOMException);
  Attr               removeAttributeNode(in Attr oldAttr)
                                        raises(DOMException);
  NodeList           getElementsByTagName(in DOMString name);
  // Introduced in DOM Level 2:
  DOMString          getAttributeNS(in DOMString namespaceURI, 
                                    in DOMString localName);
  // Introduced in DOM Level 2:
  void               setAttributeNS(in DOMString namespaceURI, 
                                    in DOMString qualifiedName, 
                                    in DOMString value)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  void               removeAttributeNS(in DOMString namespaceURI, 
                                       in DOMString localName)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  Attr               getAttributeNodeNS(in DOMString namespaceURI, 
                                        in DOMString localName);
  // Introduced in DOM Level 2:
  Attr               setAttributeNodeNS(in Attr newAttr)
                                        raises(DOMException);
  // Introduced in DOM Level 2:
  NodeList           getElementsByTagNameNS(in DOMString namespaceURI, 
                                            in DOMString localName);
  // Introduced in DOM Level 2:
  boolean            hasAttribute(in DOMString name);
  // Introduced in DOM Level 2:
  boolean            hasAttributeNS(in DOMString namespaceURI, 
                                    in DOMString localName);
};

Java Language Binding for Node

package org.w3c.dom;

public interface Node {
    // NodeType
    public static final short ELEMENT_NODE              = 1;
    public static final short ATTRIBUTE_NODE            = 2;
    public static final short TEXT_NODE                 = 3;
    public static final short CDATA_SECTION_NODE        = 4;
    public static final short ENTITY_REFERENCE_NODE     = 5;
    public static final short ENTITY_NODE               = 6;
    public static final short PROCESSING_INSTRUCTION_NODE = 7;
    public static final short COMMENT_NODE              = 8;
    public static final short DOCUMENT_NODE             = 9;
    public static final short DOCUMENT_TYPE_NODE        = 10;
    public static final short DOCUMENT_FRAGMENT_NODE    = 11;
    public static final short NOTATION_NODE             = 12;

    public String getNodeName();

    public String getNodeValue()
                                  throws DOMException;
    public void setNodeValue(String nodeValue)
                                  throws DOMException;

    public short getNodeType();

    public Node getParentNode();

    public NodeList getChildNodes();

    public Node getFirstChild();

    public Node getLastChild();

    public Node getPreviousSibling();

    public Node getNextSibling();

    public NamedNodeMap getAttributes();

    public Document getOwnerDocument();

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

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

    public Node removeChild(Node oldChild)
                            throws DOMException;

    public Node appendChild(Node newChild)
                            throws DOMException;

    public boolean hasChildNodes();

    public Node cloneNode(boolean deep);

    public void normalize();

    public boolean isSupported(String feature, 
                               String version);

    public String getNamespaceURI();

    public String getPrefix();
    public void setPrefix(String prefix)
                               throws DOMException;

    public String getLocalName();

    public boolean hasAttributes();

}

Java Language Binding for Element

package org.w3c.dom;

public interface Element extends Node {
    public String getTagName();

    public String getAttribute(String name);

    public void setAttribute(String name, 
                             String value)
                             throws DOMException;

    public void removeAttribute(String name)
                                throws DOMException;

    public Attr getAttributeNode(String name);

    public Attr setAttributeNode(Attr newAttr)
                                 throws DOMException;

    public Attr removeAttributeNode(Attr oldAttr)
                                    throws DOMException;

    public NodeList getElementsByTagName(String name);

    public String getAttributeNS(String namespaceURI, 
                                 String localName);

    public void setAttributeNS(String namespaceURI, 
                               String qualifiedName, 
                               String value)
                               throws DOMException;

    public void removeAttributeNS(String namespaceURI, 
                                  String localName)
                                  throws DOMException;

    public Attr getAttributeNodeNS(String namespaceURI, 
                                   String localName);

    public Attr setAttributeNodeNS(Attr newAttr)
                                   throws DOMException;

    public NodeList getElementsByTagNameNS(String namespaceURI, 
                                           String localName);

    public boolean hasAttribute(String name);

    public boolean hasAttributeNS(String namespaceURI, 
                                  String localName);

}