Cover Pages: XML Daily Newslink: Wednesday, 09 January 2008

A Cover Pages Publication http://xml.coverpages.org/
Provided by OASIS and Sponsor Members
Edited by Robin Cover

This issue of XML Daily Newslink is sponsored by:
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Headlines

Using XML in Internet Protocols
Complex HTML Tables Made Easy with Apache Velocity
Yahoo Tests Support for OpenID
A Health-Care Data Model Based on the HL7 Reference Information Model
An Extensible Data Format (XML) for Describing Files

Using XML in Internet Protocols
Tim Bray, IETF Tutorial

Tim Bray, Distinguished Engineer and Director of Web Technologies at Sun Microsystems provided XML tutorial material for attendees at the Seventieth IETF meeting in Vancouver, BC, Canada (2-7 December 2007). The 39 tutorial slides were used in the NETCONF Working Group session at this 70th IETF Meeting. The slides also reference IETF RFC #3470 (Scott Hollenbeck/Marshall T. Rose/Larry Masinter) "Guidelines for the Use of Extensible Markup Language (XML) within IETF Protocols." Excerpts from Bray's presentation: "Tutorial Agenda: Should you use XML? Should you invent a new XML language? If you're inventing a new XML language, how do you maximize your chances of success? Other options include: Hardwired binary, ASN.1, Plain text, and JSON. Use XML if: (a) Your data is document-flavored; (b) You're worried about i18n; (c) You're worried about extensibility; (d) You're worried about reusability. XML Schema Language Options include DTD, XSD (W3C XML Schemas), RelaxNG, and Schematron [slides are provided for each of these schema languages]. As to XML Extensibility, Three Options: No changes; 'Must-Understand' policy (e.g., as in SOAP), and 'Must-Ignore' policy (e.g., as in Atom)..."

Complex HTML Tables Made Easy with Apache Velocity
Matthias Laux, Java World Magazine

The Apache Velocity template engine simplifies creation of textual content by merging data contained in a Java object model with Velocity templates. But creating complex HTML tables with cells that span multiple columns and rows can lead to elaborate nested hierarchies of Velocity directives, which quickly render the Velocity template difficult to read and maintain. In this article Matthias Laux introduces a Java package that simplifies handling of even highly complex HTML tables, using a small number of directives while retaining all the benefits of Velocity for HTML generation. The package is independent of Apache Velocity and can potentially be used with other rendering schemes, such as JavaServer Pages. "I've worked on several projects that required generated HTML pages to display large amounts of data, typically available in a database or as XML files. To apply the well-established Model-View-Controller paradigm, I used Apache Velocity as the template engine to generate all the pages. The controller application's task was to read the data, fill in some Java data structures based on the data model for a given use case, and merge the data objects with Velocity templates. Observation about a recurring [tables] pattern led me to implement a general solution for handling complex tables in this context. Beyond basic functionality, I wanted the solution to include some convenience features, such as: (1) The ability to grow a table dynamically after instantiation; (2) Flexible behavior at the boundaries: clipping and autogrowth during cell insertion; (3) Compacting of tables; (4) Cloning of tables. This article introduces my solution: a Java package that takes the complexity out of HTML table generation with Velocity..." [Ed note: some diehard descriptive markup theorists tend to think, in the broad sense, that "[markup] tables are evil."]

See also: the package download

Yahoo Tests Support for OpenID
Jeremy Kirk, InfoWorld

Yahoo appears close to implementing its OpenID Web authentication standard, which could provide a spark for broader support for the open-source project. OpenID is referred to as a decentralized system since no one company or entity controls all of the identity information. It gives users more power to determine who they want to share their identity with and avoids the potential security problems of having a massive amount of data locked up in a single database. The system is also free. Web sites acting as an identity provider for OpenID give users a unique URL (Uniform Resource Locator). When a person encounters another Web site supporting OpenID, they can enter that URL along with the password they have registered with the identity provider, which is then verified in order to login at the new site. The person is then allowed to carry their profile or other information into the new Web site, a concept known as single sign-on. It means that people may need fewer passwords but would be able to securely share their data and login on more Web sites. A variety of companies and Web sites are supporting OpenID, such as AOL, LiveJournal, Technorati, and mobile operator Orange, which is owned by France Telecom; hundreds of other Web sites are also using OpenID. Yahoo controls a domain (me.yahoo.com), which shows a short message indicating the company will act as an identity provider for OpenID. Code on pages at Flickr.com, owned by Yahoo, could also let a person use their Flickr login and profile for logging into other OpenID-compatible sites.

See also: the OpenID web site

A Health-Care Data Model Based on the HL7 Reference Information Model
T. J. Eggebraaten, J. W. Tenner, and J. C. Dubbels; IBM Systems Journal

This article was published in an IBM Systems Journal special issue on Information-Based Medicine. The integration of medical information from various sources is gaining in importance as hospitals and medical research centers attempt to gain new insights into existing data. The Health Level Seven (HL7) organization has developed an abstract information model for health-care data, the HL7 Reference Information Model (RIM). We describe in this paper our approach to implementing a physical data model based on RIM. Our approach, which combines elements of entity-relationship data modeling and entity-attribute-value data modeling, involves the modeling of base RIM classes, RIM inheritance, and RIM data types. We incorporated the resulting data model into IBM Clinical Genomics, a product that integrates clinical and genomic data in a way that enables medical researchers to carry out clinical research. In 1997, HL7 began to work on HL7 Version 3 (HL7 V3), whose message development approach differs significantly from previous versions. All message specifications from HL7 V3 onward will be derived from the HL7 Reference Information Model (RIM). The HL7 RIM (RIM, for short) is a static model of health-care information that broadly and abstractly covers all aspects of a health-care organization's clinical and administrative information. For HL7 Version 3, the datatype specifications are found in the "Data Types Abstract Specification" and in the "V3 Data Types Implementable Technology Specification for XML". RIM is an information model for health care that broadly covers all aspects of an organization's clinical and administrative information. Health-care industry experts created RIM to support the definition of messages used for exchanging health-care information. By deriving our physical data model from RIM, we are able to take advantage of the expertise of the HL7 organization and enable the handling of HL7 V3 messages in our RIM-based database. Our design combines aspects of ER modeling with a hybrid-EAV modeling approach. The HL7 data types and the inheritance structure of the RIM classes required additional modeling considerations beyond standard ER modeling. After health-care data populates our database, the data can be restructured into specific data marts to serve the specific analytical needs of the user community.

An Extensible Data Format (XML) for Describing Files
Miguel A. Garcia-Martin and Marcin Matuszewski (eds), IETF Internet Draft

In the recent times there is a growing interest for defining a standard format for describing files and its associated meta-data. This is the case, for example, of the Session Initiation Protocol (SIP) file sharing framework, which describes a usage of SIP for publishing file metadata. Other usages, for example, based on the HyperText Transfer Protocol (HTTP - RFC 2616) have been also discussed, and it is expected that the growing usage of XML in IETF protocols will increase the demand for this format. This document creates a generic XML document format for describing files and their associated meta-data. The document format is extensible, so future needs can be addressed thorough extensions. It is expected that applications that need to describe files use this format as their standard format. As proposed: A 'file-metadata' document is an XML document that MUST be well-formed and SHOULD be valid. A 'file-metadata' document MUST be based on XML 1.0 and MUST be encoded using UTF-8. The XML schema that defines the constrains of the 'file-metadata' document provides support for full and partial 'file-metadata' documents, so that applications that can accommodate differentiated versions of XML documents can use partial content to signal a change in one or more files. The XML schema contains provisions for two root elements, namely 'file-set' and 'patch', of which only one MUST be present in a valid 'file-metadata' document...


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