Meaning
Programming interface for event-driven parsing of XML documents that processes data in a single linear pass. This method does not load the entire document into memory, making it suitable for very large files. It reports parsing events such as the start of an element or the appearance of text directly to the application.
Sequential Processing
Execution of a sax parser involves a callback mechanism where the application registers handlers for specific types of data. As the parser reads the stream, it triggers these handlers in the order the elements appear in the source. This forward-only motion means that the application cannot move backward to access previously read data without restarting the process.
Such a structure is ideal for simple extraction tasks where data is processed and immediately discarded.
Memory Efficiency
Low memory consumption is the primary advantage of this event-driven approach.
Implementation Barrier
Complexity of the application logic increases when complex relationships between distant nodes must be tracked. Developers must maintain their own state machines to remember the context of the current element within the larger document hierarchy. This requirement makes the sax parser less convenient than tree-based models for tasks involving heavy document transformation.
The lack of random access requires careful planning of the data handling logic before the first byte is read.
