ODFDOM
OpenDocument API - ODFDOM
ODFDOM is the name of the upcoming free OpenDocument framework sponsered by Sun Microsystems Inc.
It is the succesor of AODL and Odf4j, designed together with their architects to provide the ODF developer community an easy lightwork programming API, meant to be portable to any object-oriented language.
The first pre-version of the Java 5 reference implementation of ODFDOM is planned to be made public under LGPL3 in May 2008.
Overview
The ODFDOM project's objective is to provide an API for easily reading, writing and manipulating ODF documents. ODFDOM implements a layered approach through which documents are accessed.
- The ODF Package / Physical Layer - provides direct access to the resources that are stored in the ODF package, such as XML streams, images or embedded objects.
- The ODF Typed DOM / XML Layer - provides classes for all XML elements. XML attributes are mapped to class attributes. It is a typed DOM as every ODF XML element is represented by a different class, generated from the ODF RelaxNG schema. This level is concerned with the representation of the content of the standardized XML streams of the underlying package using the language independent W3C DOM API. This layer easily provides the ODF developer with all informations about the ODF XML structure.
- The ODF Document / Convenient Layer - represents components consisting of multiple underlying XML elements. This level is concerned with usability aids, which are not specified by the ODF standard.
- The Customized ODF Document / Extendable Layer - not part of the delivered API, but part of the design. This level is concerned with user defined customizations.
ODFDOM is part of the odftoolkit project. Development is discussed on the dev@odftoolkit.openoffice.org mailing list.
The ODFDOM Layers
The typed DOM / XML Layer
At this level, only the by ODF standardized XML file streams of the document are accessible via the W3C DOM API.
For instance the XML of an ODF table File:FruitTable code.jpg
Would be mapped to a W3C derived ODF DOM File:Table fruits diagramm.jpg
The XML DOM Layer sources are organized beyond org.openoffice.odf.dom.*
Its sources are all generated from the RelaxNG schema using the following naming conventions:
- The Class name is equal to the element name using 'Odf' as an Prefix and 'Element' as Suffix.
- Elements are stored beyond a sub-package equal to their Namespace used by the OOo.
For instance, the frame element 'draw:frame' would be generated as class org.openoffice.odf.dom.draw.OdfFrameElement
Note: Java dependent helper classes, which are not part of the official API, but for convenient part of the module are delivered beyond org.openoffice.odf.java.*
The following example illustrates how to add a graphic to the ODF document, that it is viewable:
import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathFactory; import org.openoffice.odf.doc.OdfDocument; import org.openoffice.odf.dom.text.OdfParagraphElement; import org.openoffice.odf.java.OdfNamespaceContext; import org.w3c.dom.Document; [...] // loads the ODF document from the path OdfDocument odfDoc = OdfDocument.load("/home/myDocuments/myVacation.odt"); // get the ODF content as DOM tree representation Document odfContent = odfDocument.getContent(); // XPath initialization ''(JDK5 functionality)'' XPath xpath = XPathFactory.newInstance().newXPath(); xpath.setNamespaceContext(new OdfNamespaceContext()); // receiving the first Paragraph "//text:p[1]" ''(JDK5 functionality)'' OdfParagraphElement para = (OdfParagraphElement) xpath.evaluate("//text:p[1]", docContent, XPathConstants.NODE); // adding an image - expecting the user to know that // an image consists always of a 'draw:image' and a 'draw:frame' parent para.createDrawFrame().createDrawImage("http://myweb.org/images/myHoliday.png", "/Pictures/myHoliday.png");