14.4. Manipulating an XML Document


You want to represent an XML document as a C++ object so that you can manipulate its elements, attributes, text, DTD, processing instructions, and comments.


Use Xerces’s implementation of the W3C DOM. First, use the class xercesc::DOMImplementationRegistry to obtain an instance of xercesc::DOMImplementation, then use the DOMImplementation to create an instance of the parser xercesc::DOMBuilder. Next, register an instance of xercesc::DOMErrorHandler to receive notifications of parsing errors, and invoke the parser’s parseURI() method with your XML document’s URI or file pathname as its argument. If the parse is successful, parseURI will return a pointer to a DOMDocument representing the XML document. You can then use the functions defined by the W3C DOM specification to inspect and manipulate the document.

When you are done manipulating the document, you can save it to a file by obtaining a DOMWriter from the DOMImplementation and calling its writeNode() method with a pointer to the DOMDocument as its argument.

Example 14-10 shows how to use DOM to parse the document animals.xml from Example 14-1, locate and remove the node corresponding to Herby the elephant, and save the modified document.

Example 14-10. Using DOM to load, modify, and then save an XML document

#include <exception> #include <iostream> // cout #include <xercesc/dom/DOM.hpp> #include <xercesc/framework/LocalFileFormatTarget.hpp> #include <xercesc/sax/SAXException.hpp> ...

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