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Non validating sax parser

For a more detailed comparison, see When to Use SAX.

Setting up a program to use SAX requires a bit more work than setting up to use the Document Object Model (DOM).

Instead, SAX simply sends data to the application as it is read; your application can then do whatever it wants to do with the data it sees.

Pull parsers and the SAX API both act like a serial I/O stream.

The following code in the when it encounters problems, and defines the command-line options which are required to tell the application the name of the XML file to be processed.For those reasons, developers who are writing a user-oriented application that displays an XML document and possibly modifies it will want to use the DOM mechanism described in Chapter 3, Document Object Model.However, even if you plan to build DOM applications exclusively, there are several important reasons for familiarizing yourself with the SAX model: It is helpful to understand the SAX event model when you want to convert existing data to XML.Other command line arguments in this part of the code will be examined later in this chapter, when we start looking at validation. Characters found within the element are passed as an array of characters, along with the number of characters (length) and an offset into the array that points to the first character.The following code handles the start-document and end-document events: public class SAXLocal Name Count extends Default Handler { private Hashtable tags; public void start Document() throws SAXException [...] public void end Document() throws SAXException private static String convert To File URL(String filename) { [...] method is invoked, to get the names and counts of the elements contained in the hash table, and print out a message onscreen to tell the user how many incidences of each element were found.So it is easy to vary the way you process text (for example), because you can process it multiple places in the program (for more detail, see Further Information).SAX requires much less memory than DOM, because SAX does not construct an internal representation (tree structure) of the XML data, as a DOM does.So if the application does not generate an exception, then the default error-event handler generates one.But for nonfatal errors and warnings, exceptions are never generated by the default error handler, and no messages are displayed.SAX is an event-driven model (you provide the callback methods, and the parser invokes them as it reads the XML data), and that makes it harder to visualize.Finally, you cannot "back up" to an earlier part of the document, or rearrange it, any more than you can back up a serial data stream or rearrange characters you have read from that stream.

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