Primarily used for transformation or extraction, it features filters, visitors, custom tags and easy to use JavaBeans. It is a fast, robust and well tested package. What has attracted most developers to HTMLParser has been its simplicity in design, speed and ability to handle streaming real-world html.
The underlying data can be either internal or plug-in, and both can be in binary XML. Plug-in Data Plug-in data is data that has already been parsed and therefore can be transferred from one processor to another without requiring parsing.
Users can also plug in their own implementations. The InfosetReader retrieves sequential events from the XML stream and queries the state and data from these events. In the following example, the XML data is scanned to retrieve the QNames and attributes of all elements: InfosetReader reader; While reader.
To support shadow copy of DOM across documents, a new copy of InfosetReader can be created to ensure thread safety, using the Clone method.
To support lazy materialization, the InfosetReader may have the ability to move focus to any location specified by Offset Optional. Users cannot modify this implementation. You can save the XML text as either of the following: You can save the section reference of binary XML instead of actual data, if you know that the data source is available for deserialization.
The following example illustrates how to save as binary XML. The rest of the DOM tree can be expanded later if it is accessed. A node may have unexpanded child and sibling nodes, but its parent and ancestors are always expanded.
Each node maintains the InfoSetReader. Offset property of the next node so that the DOM can pull data additional to create the next node. Depending on the access method type, DOM nodes may expand more than the set of nodes returned: DOM Navigation The DOM navigation interface allows access to neighboring nodes such as first child, last child, parent, previous or next sibling.
If node creation is needed, it is always done in document order. In the case of scalable DOM, retrieval by index does not cause the expansion of all previous nodes, but their ancestor nodes are materialized.
XPath Expressions XPath evaluation can cause materialization of all intermediate nodes in memory. Supporting DOM navigation requires adding cross references among nodes.
In automatic dereferencing mode, some of the links are weak references, which can be freed during garbage collection. Node release is based on the importance of the links: Links to parent nodes cannot be dropped because ancestors provide context for in-scope namespaces and it is difficult to retrieve dropped parent nodes using streaming APIs such as InfosetReader.
The scalable DOM always holds its parent and previous sibling strongly but holds its children and following sibling weakly. When the Java Virtual Machine frees the nodes, references to them are still available in the underlying data so they can be recreated if needed.Java: Simple Way to Write XML (DOM) File in Java Last Updated on July 17th, by App Shah 36 comments As we learned “ Simple way to count number of XML elements in Java ” earlier, here is another simple Java code which writes XML file in Java (DOM Parser).
How to write XML file in Java (DOM Parser) Pankaj 10 Comments Earlier we learned how to read XML file and how to edit XML file in java using DOM Parser, today we will learn how to write an XML file in java using DOM Parser.
DOM parser provides several Java interfaces and methods to work with the XML data. It returns a tree structure of all the elements in a XML document. And the tree can be traversed to work with the data.
SAX parser is working differently with a DOM parser, it neither load any XML document into memory nor create any object representation of the XML document.
Instead, the SAX parser use callback function feelthefish.comtHandler to informs clients of the XML document structure.
SAX Parser is faster and uses less memory than DOM parser. DOM parser parses the entire XML document and loads it into memory; then models it in a “TREE” structure for easy traversal or manipulation. In short, it turns a XML file into DOM or Tree structure, and you have to traverse a node by node to get what you want.
DOM provides many handy classes to create XML file easily. Firstly, you have to create a Document with DocumentBuilder class, define all the XML content – node, attribute with Element class.
In last, use Transformer class to output the entire XML content to stream output, typically a File.