Xml and xml processor
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This document summarizes a seminar on XML and XML processors. It introduces XML and compares it to HTML. It describes the structure of an XML document including the prolog, data instance, and logical and physical structures. It also discusses XML processors and parsers, including DOM and SAX parsers. The document provides examples of DOM and SAX parsing approaches.
Xml and xml processor
- 1. Seminar On: XML & XML Processor Submitted By: Himanshu Soni Branch: CS Roll No: 1301410040 Subject: Web Technolgy (NCS-504) Introduction to XML HTML Vs XML Structure of XML Document XML Processor Parser DOM & SAX References
- 2. Introduction to XML What is XML ? XML is an acronym for “eXtensible Markup Language”. XML is a markup language derived from SGML (Standard Generalised Markup language). It is used to store data in structured format.
- 3. HTML vs XML HTML XML HTML document formats and displays web page data. XML document carry data along with their description. Predefined tags (Predefined markup language). Not have predefined tags.You can create and define new tags as per your needs.(Meta Language). May not have closing tag. Must have closing tag. Not Case Sensitive. Case Sensitive. Directly Viewable in browser. Viewable if proper Stylesheet provided.
- 5. Structure of XML Document System A style sheet presentation through CSS or XSL. A grammer structure through DTD. A semantics of data through XML file. Semantics and data, XML file Grammer Structure, DTD Syle-sheet, CSS or XSL
- 6. Structure of XML file XML file has – -a logical structure and - a physical structure Logical Structure: It refers to different parts of document i.e., how document is built. Physical Structure: It refers what document actually contains.
- 7. Logical Structure -prolog (preface or introduction to XML document) -data instance (the real or actual data) Prolog Data Instance An XMl declaration Processing Instruction A document type definition Comments White Spaces Element types, tags and names White Spaces
- 8. Prolog XML declaration <? xml version=“1.0” encoding= “UTF-8” standalone=“no” ?> Processing Instruction <? xml-stylesheet type=“text/css” href=“main.css” ?> Document Type Declaration (DTD) <! DOCTYPE rootElement SYSTEM DTD_File_Name.dtd> Comments <!– Listen Here --> White Spaces Spaces, tabs, linebreak
- 9. XML Processor When a software program reads an XML document and takes actions accordingly, this is called processing the XML. Any program that can read and process XML documents is known as an XML processor. An XML processor reads the XML file and turns it into in-memory structures that the rest of the program can access.
- 10. What is Parser? The word parser comes from compilers. In a compiler, a parser is the module that reads and interprets the programming language. Parsers are software components that decode XML files on behalf of the application There are two basic ways to interface a parser with an application: -object-based interfaces -event-based interfaces
- 11. Architecture of XML Program Divided into two parts: • The parser deals with the XML file. • The application consumes the content of the file through the parser. Here application can be very simple (such as printing information on the screen), or quite complex (such as a browser or an editor)
- 12. Object-based Interface Using an object-based interface, the parser explicitly builds a tree of objects that contains all the elements in the XML document. Tree-based parsers deal generally small documents Example- <?xml version=”1.0”?> <products> <product> <name>XML Editor</name> <price>499.00</price> </product> <product> <name>DTD Editor</name> <price>199.00</price> </product> <products>
- 13. Building the tree of objects
- 14. Event-based Interface With an event-based interface, the parser does not explicitly build a tree of objects. Instead, it reads the file and generates events as it finds elements, attributes, or text in the file. There are events for element starts, element ends, attributes, text content, entities, and so on. Event-based parsers deal generally used for large documents An event-based API
- 15. DOM The Document Object Model (DOM) is an application programming interface (API) for HTML and XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated Programmers can build documents, navigate their structure, and add, modify, or delete elements and content i.e. The API allows for constructing, accessing and manipulating the structure and content of XML documents Basically, DOM is object based parser
- 16. DOM DOM Parser DOM TreeXML File A P I Application
- 17. SAX SAX (Simple API for XML) is an event- driven algorithm for parsing XML documents. SAX provides a mechanism for reading data from an XML document. SAX parsers operate on each piece of the XML document sequentially. SAX parsing is unidirectional; previously parsed data cannot be re-read without starting the parsing operation again
- 18. SAX vs DOM Parsing: Efficiency The DOM object built by DOM parsers is usually complicated and requires more memory storage than the XML file itself A lot of time is spent on construction before use For some very large documents, this may be impractical SAX parsers store only local information that is encountered during the serial traversal. Hence, programming with SAX parsers is, in general, more efficient but difficult to implement sonetime.
- 19. References Benoit Marchal. XML by Example. 1 edition. QUE (14 December 1999) Pankaj Sharma. Introduction to Web Technology. S.K. Kataria & Sons Sumita Arora. Informatics Practices. Dhanpat Rai & Co. (P) Ltd., Delhi 2010 https://en.wikipedia.org/wiki/XML