Simple API for XML

Introduction

Simple API for XML (SAX) is a standard interface for event-driven XML parsing. It was developed by the members of the XML-DEV mailing list, providing a mechanism for reading data from an XML document that is faster and uses less memory than the DOM.

Overview

SAX is an event-driven online algorithm for parsing XML documents, with an API developed by the XML-DEV mailing list. SAX provides a mechanism to read data from an XML document that is faster and uses less memory than the DOM. As the document is read, the SAX parser calls the method corresponding to the document's content.

A computer with lines of code displayed, representing the SAX parsing process

Working of SAX

SAX parsers work on each piece of the XML document sequentially, invoking a callback function when it encounters certain elements (like the start or end of an element). This is different from the DOM, which requires the entire document to be loaded into memory before it can be parsed.

Advantages of SAX

SAX parsers are read-only and provide no random access to the document. This is generally much faster and uses less memory than a DOM parser. The trade-off is that a SAX parser cannot modify the document in any way.

Disadvantages of SAX

The main disadvantage of SAX is that if the XML document represents hierarchical data, the client program receiving events from the SAX parser may need to build its own stack to remember the hierarchy of elements.

Applications of SAX

SAX is widely used in XML parsing, it is the base for XML processing in languages like Java. It is also used in information retrieval systems, where the whole document is not relevant for the queries.