Tmql4j is one of the first query engines for TMQL, the Topic Maps Query Language. It was initially released a few months ago, supporting the 2008 TMQL draft. Today version 2.6.3 supporting the 2010 TMQL draft was officially released and features lots of new features.

• New language processing - the two core modules ( the lexical scanner and the parser ) were rewritten to become more flexible and stable. The lexical scanner provides new methods to register your own language tokens ( as language extension ) or your own non-canonical tokens.
• New query factory - now it is possible to implement your own query types. If the query provides a transformation algorithm, it may be converted to a TMQL query and processed by the tmql4j engine.
• Default prefix - the engine provides the functionality of defining a default prefix in the context of the runtime. The prefix can be used without a specific pattern in the context of a query.
• New interfaces - the interfaces were reorganized to enable an intuitive usage and understanding of the engine itself.

In addition to the official release the google code project of tmql4j was restructured to provide additional plug-ins for the query engine suite. The Topic Maps query engine was reorganized to support a lightweight plug-in deployment for applications. Plug-ins have to implement simple interfaces to enable the interaction with the core engine. The communication is fully based on the Java services framework and does not require any code changes. The suite currently contains the following plug-ins:

• Tmql4Ontopia - A bridge implementation for using the query engine as a query processor in the Ontopia Topic Maps browser Omnigator. The modifications necessary to the of the Ontopia source code are already commited to the Ontopia project. Now the engine provides an alternative to the embeded TOLOG query processor.
• TmqlDraft2010 - In 2010, the draft of TMQL was significantly changed. The tmql4j developer team decided to implement the new draft as plug-in to provide the old and new draft within one engine. The new draft currently contains a path syntax like XPath to query a Topic Maps engine.
• TopicMapModificationLanguage - In addition to the original draft, the Topic Maps Lab developed TMQL part 2 containing the modification language. The plugin provides four new top level expressions to insert new content, remove or modify existing ones and merge subjects. TMQL Part 2, Update Language, is not yet standardized but is currently the only way to modify a topic map without moving back to other solutions like TOLOG or APIs.

The tmql4j suite is open source and available here. Feel free to use it, submit any issues you find so we can fix them or contribute patches yourself. You can also write your own plug-ins to extend the query engine.