Why sax instead of dom

Decompression reduces performance. If you are transferring files between client and server, then HTTP compression can be easier. Compression is supported only in the XDK Java components. A new DOMParser is called. Use the XMLParser. The example uses: parser. All Rights Reserved. URL; import org. Node; import org. Element; import org. Document; import org. NodeList; import org. NamedNodeMap; import oracle.

DOMParser; import oracle. The XMLReader interface contains two important enhancements over the old parser interface: It adds a standard way to query and set features and properties.

It adds Namespace support, which is required for many higher-level XML standards. Table lists the SAXParser methods. String name Looks up the value of a feature getProperty java. String name, boolean value Sets the state of a feature setProperty java. String name, java. Object value Sets the value of a property. Parser; import org. Locator; import org. AttributeList; import org.

HandlerBase; import org. InputSource; import org. SAXException; import org. SAXParseException; import oracle.

XMLDocumentHandler; import oracle. NSName; import oracle. SAXAttrList; import oracle. Only the new startElement and endElement interfaces are implemented here. All other interfaces are implemented in the class HandlerBase. Creating a Node with a Value to Be Set Later If you check the DOM specification, referring to the table discussing the node type, you will find that if you are creating an element node, its node value is null , and cannot be set.

Using the XMLNode. Loop while enum. You get the following error: oracle. Any well-formed document in any supported encoding can be successfully parsed using the following sample code: import java. The following example shows how to avoid these problems: mport java. Using System. General Questions About XML Parser for Java These are general questions: Including Binary Data in an XML Document There is no way to directly include binary data within the document; however, there are two ways to work around this: Binary data can be referenced as an external unparsed entity that resides in a different file.

DOMParser to parse the document. Table lists the oraxml command line options. Table oraxml: Command Line Options Option Purpose - comp fileName Compresses the input XML file - decomp fileName Decompresses the input compressed file - dtd fileName Validates the input file with DTD Validation - enc fileName Prints the encoding of the input file - help Prints the help message - log logfile Writes the errors to the output log file - novalidate fileName Checks whether the input file is well-formed - schema fileName Validates the input file with Schema Validation - version Prints the release version - warning Show warnings.

All rights reserved. Contents Index. DTD Validating Mode. Partial Validation Mode. Schema Validation Mode. The validator tries to validate part or all of the instance document as long as it can find the schema definition. The validator tries to validate the whole instance document, raising errors if it cannot find the schema definition or if the instance does not conform to the definition. Auto Validation Mode. A sample application to regenerate the SAX events from the compressed stream. Enables an application to register a content event handler.

Deprecated as of SAX2. Enables an application to register an error event handler. String name, boolean value. Object value. With an explicit encoding 1 argument, the result is a byte string in the specified encoding. With no encoding argument, the result is a Unicode string, and the XML declaration in the resulting string does not specify an encoding. The standalone argument behaves exactly as in writexml. Return a pretty-printed version of the document. The encoding argument behaves like the corresponding argument of toxml.

This example program is a fairly realistic example of a simple program. In this particular case, we do not take much advantage of the flexibility of the DOM. Interfaces are accessed through instance objects. Applications should not instantiate the classes themselves; they should use the creator functions available on the Document object.

Derived interfaces support all operations and attributes from the base interfaces, plus any new operations. Operations are used as methods. Since the DOM uses only in parameters, the arguments are passed in normal order from left to right. There are no optional arguments. IDL attributes map to instance attributes. The types short int , unsigned int , unsigned long long , and boolean all map to Python integer objects.

DOMException is currently not supported in xml. Instead, xml. These objects provide the interface defined in the DOM specification, but with earlier versions of Python they do not support the official API. And so on You could read through megabytes and megabytes of XML this way, just extracting the tiny amount of data you need.

The negative side of this approach is of course, that you need to do a lot more book-keeping yourself, depending on what data you need to extract and how complicated the XML structure is. Furthermore, you naturally cannot modify the structure of the XML tree, because you never have it in hand as a whole. So in general, SAX is suitable for combing through potentially large amounts of data you receive with a specific "query" in mind, but need not modify, while DOM is more aimed at giving you full flexibility in changing structure and contents, at the expense of higher resource demand.

You're comparing apples and pears. There are many different parsers, and "event-based" refers to the parsing method. The document object model DOM is an abstract data model that describes a hierarchical, tree-based document structure; a document tree consists of nodes , namely element, attribute and text nodes and some others.

Nodes have parents, siblings and children and can be traversed, etc. A DOM structure may be serialized , i. For a computer to manipulate, or even display, a DOM tree from a file, it has to deserialize , or parse , the file and reconstruct the abstract tree in memory.

This is where parsing comes in. Now we come to the nature of parsers. One way to parse would be to read in the entire document and recursively build up a tree structure in memory, and finally expose the entire result to the user.

I suppose you could call these parsers "DOM parsers". That would be very handy for the user I think that's what PHP's XML parser does , but it suffers from scalability problems and becomes very expensive for large documents. On the other hand, event-based parsing, as done by SAX, looks at the file linearly and simply makes call-backs to the user whenever it encounters a structural piece of data, like "this element started", "that element ended", "some text here", etc. This has the benefit that it can go on forever without concern for the input file size, but it's a lot more low-level because it requires the user to do all the actual processing work by providing call-backs.

To return to your original question, the term "event-based" refers to those parsing events that the parser raises as it traverses the XML file. The Wikipedia article has many details on the stages of SAX parsing. Both has advantages and disadvantages and can be used in our programming depending on the situation. If we need to find a node and does not need to insert or delete we can go with SAX itself otherwise DOM provided we have more memory.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Ask Question. Asked 10 years, 3 months ago. Active 3 years, 2 months ago. It defines an interface that enables programs to access and update the style, structure, and contents of XML documents. What is Dom and its use? The DOM is designed to be used with any programming language. What do you mean by parsing? Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar.

The term parsing comes from Latin pars orationis , meaning part of speech. What is produced by a SAX parser? Tokens are processed in the same order that they appear in the document.