The org.xml.sax.ext.DeclHandler Handler

Members

Overview

This interface defines methods that receive notification of specific events within a DTD, such as element and attribute declaration. This is another item only good for very specific cases, again, XML editors and components that must know the exact lexical structure of documents and their DTDs come to mind. This interface defines callbacks that gives specific information about DTD declarations. Element and attribute definitions invoke the appropriate callback with their name (and the element names for attributes) as well as constraint information. While this is a fairly rigid set of data for attributes, elements only receive a string with the constraint model as pure text. Additionally, internal and external entity reference notifications are defined.

Method Overviews

The implementation of methods in this class depends upon your application. However I have given examples of method which I have used in my application so thought might be interested too.

Example of attributeDecl()

/**

   * This method reports an attribute type declaration i.e. <!ATTLIST> in DTD.

   * @param eName The name of the associated element.

   * @param aName The name of the attribute.

   * @param type A string representing the attribute type.

   * @param valueDefault A string representing the attribute default ("#IMPLIED", "#REQUIRED", or "#FIXED") or null if none of these applies.

   * @param value A string representing the attribute's default value, or null if there is none.

   */

  public void       attributeDecl(String eName, String aName, String type, String valueDefault, String value)

  {

    System.out.println("Start of attributeDecl");

    System.out.println("eName :"+eName);

    System.out.println("aName :"+aName);

    System.out.println("type :"+type);

    System.out.println("valueDefault :"+valueDefault);

    System.out.println("value :"+value);

    System.out.println("End of attributeDecl");

  }

Example of elementDecl():

/**

   * This method reports an element type declaration(<!ELEMENT) in DTD.

   * @param name The element type name.

   * @param model The content model as a normalized string.

   */

  public void       elementDecl(String name, String model)

  {

    System.out.println("Start of elementDecl");

    System.out.println("name :"+name);

    System.out.println("model :"+model);

    System.out.println("End of elementDecl");

  }

Example of How to use DeclHandler:

   DeclHandlerImpl declhandlerImpl = new DeclHandlerImpl();

    parser.setProperty("http://xml.org/sax/properties/declaration-handler",declhandlerImpl); //If the reader does not support declaration events, it will throw a SAXNotRecognizedException or a SAXNotSupportedException when you attempt to register the handler.

/**

*Before using this ensure that your xml file contains DOCTYPE declaration with a DTD.

**/

<!DOCTYPE purchaseOrder SYSTEM "E:\topxml\purchaseorder.dtd">