<P>
Over the last few months we developed the concept of 
Adaptive Plug and Play Components (APPCs)
in our research group which resulted in an OOPSLA '98 paper
by Mezini and Lieberherr.
we got very good reviews such as the one in the following paragraph.

<P>
This is the kind of work that the software industry needs most.
Hard core work, aimed at developing tangible and implementable
mechanisms to help bridge the chasm between illusive design methodologies of
arrows, bubbles, use cases, processes, etc.,
and the tough reality of the programmers in the trenches.
Even the simple observation
and unequivocal statement that a design segment should
be a distinct lingual construct,
have formal parameters that can be matched
against several locations in the class
graph merits honorable publication,
since most previous work tried and failed to
do so while using existing programming constructs (see e.g., observer pattern
implementations using inheritance and templates). There is however in the paper
much more than that, ...

<P>
The OOPSLA '98 paper has benefited from collaboration between
EDCS participants.
Don Batory from UT Austin had a paper on a related topic (mixin layers)
at ECOOP '98. 
Batory's paper was for me one of the motivators for the APPCs.

<P>
APPCs go back to Helm's and Holland's
specification contracts and Holland's implementation contracts
described in his 1993 thesis at Northeastern.
APPCs advance contracts because they are written with respect
to a filter which allows to focus only on the important participants.

<P>
We further developed and refined
traversal strategies which are a new modeling tool 
for succinct traversal specifications.
Our measurements show that a large percentage 
of the execution time
of object-oriented applications is spent during object traversal.
Traversals are ubiquitous and this
insight justifies the development of traversal strategies
as well as efficient implementations of them.
The new contribution of traversal strategies is that
traversals are now modeled as general graphs while before they
were only series-parallel graphs. We also developed
a significantly better compilation algorithm for the general
case which outperforms our earlier algorithms for
the special cases.

We discovered a new use of traversal strategies: as a tool
to match interface class graphs to implementation class graphs.
This graph matching view of 
strategies lead us to the definition of different relations between
graphs and the study of their computational
complexity. We also looked into connections between the
different relations.

<P>
The Demeter/Java compiler has been improved significantly over the
last year. See:
http://www.ccs.neu.edu/research/demeter/DemeterJava (CHANGES file)
gives the chronological order of the improvements.
The core of the adaptive compilation technology has been encapsulated into
a Java package, called TG, for use in other projects.
Jens Palsberg at Purdue University considers including it in his JTB tool.

<P>
The AP Studio tool (the GUI for adaptive programming in a visual
style) has been brought to the latest state of the art of the AP
concepts. It supports now visual strategy graph development
and building class graphs so that they can be automatically translated
into a grammar.

<P>
Jens Palsberg and his team have built an elegant tool which extends the JavaCC
technology with a traversal/visitor programming style resulting
in his JTB tool
(http://www.cs.purdue.edu/homes/taokr/jtb/index.html).
JTB good very good reviews from its user community (see the User Comments
section of the JTB page).


<P>
Our technology has been used by several companies.
(http://www.ccs.neu.edu/research/demeter/center/DemInAction.html
http://www.ccs.neu.edu/research/demeter/evaluation/success.html)
They include HP (using a traversal-visitor style to
implement their printer installation software), 
a Wall Street company (SUN Microsystem got a porting
contract from this company to port a Demeter application from
HP to Solaris; SUN requested the source code for 
Demeter/C++).
GTE Laboratories used Demeter/Java to implement the EEL compiler.
ScanSoft used Demeter/Java to prototype a C++ to COM tool.
Motorola used Demeter/Java to implement a design pattern code
generator.
Tendril Software Inc. (I am on their advisory board)
uses traversals
as an integral concept of Structure Builder.
At the Jet Propulsion Laboratory they have used the Law of
Demeter (which was the source for Adaptive Programming)
for several  years with success.  See:
http://www.ccs.neu.edu/research/demeter/
demeter-method/LawOfDemeter/Smyth/

<P>
The language D has been developed in collaboration with Xerox PARC
by Cristina Lopes whose Ph.D. thesis was completed
by Nov. 1997.
The committee consisted of Karl Lieberherr, advisor; Gregor Kiczales,
co-advisor; Boaz Patt-Shamir and Mitchell Wand.
D is an application of aspect-oriented programming to
distributed object-oriented programming and it supports the
synchronization aspect and the remote invocation aspect.
Both aspects are integrated into Demeter/Java at Northeastern
and at Xerox PARC D is implemented directly for Java without AP
(-> Aspect/J).

<P>
To implement the D-aspects RIDL and COOL for Demeter/Java, we developed a 
weaving language for Java, called DJW (Demeter-Java-Weaver)
Currently we translate all components of an adaptive program into DJW.
The DJW tool compiles the DJW instructions into executable Java
programs. DJW is a compile-time weaving language which localizes
the typical processing needed for aspect files.
This processing is reused for RIDL, COOL and an interoperability aspect
for Java beans.

<P>
We continued our discussion with the patent office regarding
our application for a US patent for compiling Adaptive Programs.
The current status is summarized in:
http://www.ccs.neu.edu/home/lieber/patent-office.html

<P>
The journal version of our SIGSOFT '96 paper
was accepted by IEEE Transactions on 
Software Engineering after the first review. 
http://www.ccs.neu.edu/research/demeter/biblio/context.html
Our paper on traversal strategies has been
completed and was submitted to the Journal of the ACM.
http://www.ccs.neu.edu/research/demeter/biblio/strategies.html