"Synthetic" mediator connecting two
mediators acting as sources (using data from INSPEC and BIBLIO)
MOBIE client
Next major milestone (end of August):
stable version of improved wrapper-generatorfully
functional wrappers for SYBASE, BIBLIO, INSPEC
stable and functional mediator specification
interpreter consisting of view expander, optimizer, and execution
enginemediator using real wrappers as sources, synthetic mediator
Status of Individual Components
We are now where we wanted to be about 6 months ago.
MSL is our internal language our wrappers support the same syntax
that is emitted by the mediators, LOREL is user query language,
post-processing in wrappers (making available a large class of
"logically supported queries"), "user-friendly"
templates written as MSL rules, object fusion in mediators.
Wrapper
New (more modular) design with well-defined components:
driver, parser, matcher, execution engine, and native component
(generating a wrapper requires only changes to the native component!)
Support for directly supported queries, indirectly
supported queries, and logically supported queriesprevious version
only handled directly and some indirectly supported queries
Cleaner templates using MSL syntax, separation
of template rules and schema
Diffferent views of the same source
Reuse of mediator execution engine:
post-processing: given a filter and the results
of the source, filters out the objects that do not match the predicates
in the filter
several build-in predicates (eq, ne, gt, lt,
contains, etc.)
Total of appr. 5000 lines of mostly C++ code
not counting the components that are shared by the mediator (engine:
4000, parser 1260)
Driver: 25
Matcher: 2275
INSPEC: 675
BIBLIO: 500
SYBASE: 650
Marcus, Svetlozar
Mediator
Generates and uses objet-IDs
New version of our mediators feature object fusion
(based on object-id); no object fusion possible with previous
execution engine (see below)
Updated query decomposition module: unification
for MSL patterns
New version of query optimizer (join ordering
based on cost information about the sources)
New, more reliable execution engine:
executes a query plan (generated by the optimizer)
fuses objects based on OIDs
returns the answer of the query
The mediator specification interpreter currently
consists of roughly 7500 lines of (mostly) C++ code
Engine: 4000
Parser: 1250
Yannis, Ramana
MOBIE
New, re-designed look-and-feel: three frames
that handle query input, result output, as well as controls (i.e.,
FAQ, formatting, navigation buttons)
Streamlined the way users can change the formatting
of results
Ability to input MSL as well as LOREL queries-MOBIE
will automatically convert LOREL queries into an equivalent MSL
query by invoking a translator (Jun Yang)
Total of appr. 4500 lines of C code
Andy
Total lines of TSIMMIS code:
6000 (SSL/CSL) + 4500 (MOBIE) + 5000 (wrappers) + 7500 (mediator
spec. interpreter) = 23,000
General
Introducing software engineering methodologies
into the design & implementation process
better documentation, better organization code
versioning tool, etc.
increased communication among team members (e.g.,
regular meetings, write-ups)
code reviews
FYI, I have compiled a document describing the
TSIMMIS development process…
Less than a month away from reaching a major
milestone (code freeze)
Moving into phase II of the Tsimmis project:
DARPA contract officially ends this summer, Dave Gunning has promised
us additional funding , focus on tech transfer (AFV Project with
TASC, Global InfoTech) and various joint projects with ISX, Lockheed
(SILK proposal). The important goal of DARPA is to "ruggedize"
our code and insert into BADD.
Future Plans
Status Information
We are in the process of modifying our servers to
generate misc. status information (what is currently going on…)
that will be displayed in MOBIE. This is not to be mistaken with
the usual error messages that are generated.
Each server has a corresponding "status server",
server and "status server" communicate via file (for
now), MOBIE connects to both.
This work is done by Rohan
"Bi-lingual" Components
Every component in Tsimmis can accept either MSL
or LOREL queries. Need to build MSL2LOREL translator (Jun)
Wrapper for US Marshalls Web Site
We are currently building a wrapper for a WWW site
(US Marshalls-15 Most Wanted Criminals) that will be used by ISX
in a prototype for a commercial product (ISLE project). Arturo
has build a configurable Python script that extracts the desired
information form specified HTML pages. The output of Arturo's
script is a file that is used as a source to our wrapper (much
like the existing BIBLIO wrapper).
This work is done by Arturo (script) and Andy (wrapper)
Transition from CSL/SSL to CORBA
Out of our own frustration with the existing communications
protocol and due to pressure from our funding agencies we have
decided to move to CORBA.
Based on some implementation of CORBA (ORBIX,
ILU, etc.)
Simpler than CSL/SSL (fetch operations)
Includes server for continuous queries
Based on DL libraries protocol
Need to develop together with partners (ISX,
Lockheed, etc.)
Task force: Joachim, Ramana, Tom, Roy
Additional Functionalities
Continuous queries: "run this query once
a day and send me the new changes"