Pattern Languages of Programs (PLoP™) conference is a premier event for pattern authors and pattern enthusiasts to gather, discuss and learn more about patterns and software development.

The conference program is almost complete, so only a few of this page may be further updated.

The conference schedule is available below and soon it will be available also as a printable document.

We invite all participants to get ready for the conference!

Conference at a Glance

The BootCamp, a special full-day Pre-PLoP activity for newcomers, will happen on Wednesday, 5th September, 8h30-17h00.

The PLoP conference starts on Wednesday evening, September 5th, at 18h00, with the traditional Papa Dell's Pizza welcome reception, and it will conclude on Saturday afternoon, September 8th.

Invited Talks

Design Beyond Human Abilities

Richard P. Gabriel, Thursday, 6th, 19:00-20:30

For 50 years we've been developing a science and practice of software based on understandings and explorations of software systems of modest size-centering on systems of a few tens of thousands of lines of code but extending up to about 50 million lines. Scale makes a difference: scale of time and of size. The prospect of ultra large scale software systems-systems with perhaps trillions of lines of code encompassing millions of processors, ranging from sensors the size of dust to the largest servers, with much of it with real-time requirements-will change everything. Imagine, if you can, how such systems will be made. Can they truly be said to be designed at all? The realities of such systems will force us to re-examine the very foundations of computing and software engineering; our concepts of abstraction, modularity, information hiding, pure static typing, and many other things will need to be refined, expanded, or reformulated. Consider, further, that such systems in normal circumstances cannot be routinely re-installed nor globally rebooted, and when used in life-critical situations, they must not stop. Data must be readable and usable for decades, even as standards and hardware changes.

This talk will examine the nature of such systems, especially how they are designed, built, and what is needed to keep them running. We'll take both a philosophical and technical look at some of the aspects of ultra large scale software that make us need to revise our foundations and what those revisions will be like.

Richard P. Gabriel is a Distinguished Engineer at IBM Research, looking into the architecture, design, and implementation of extraordinarily large, self-sustaining systems. He is the award-winning author of four books and a poetry chapbook. He lives in California.

Are Agilists the Bonobos of Software Development?

Linda Rising, Friday, 7th, 11:00-12:00

The chimpanzees and the bonobos are the animals whose genetic make-up is closest to that of human beings, but their ""cultures"" (and, yes, these animals definitely have well-defined cultures) are very different. The chimpanzees are aggressive, and operate in a strict, alpha-male-dominated hierarchy, while the bonobos are gentle and promiscuous! What sort of tie-could this have for those of us who favor agile development over plan-driven?

Linda Rising has a Ph.D. from Arizona State University in the field of object-based design metrics and a background that includes university teaching and industry work in telecommunications, avionics, and strategic weapons systems. An internationally known presenter on topics related to patterns, retrospectives, agile development approaches, and the change process, Linda is the author of numerous articles and four books---Design Patterns in Communications, The Pattern Almanac 2000, A Patterns Handbook, and Fearless Change: Patterns for Introducing New Ideas, written with Mary Lynn Manns. Find more information about Linda at

Patterns of Enterprise Application Architecture

Ralph Johnson, Saturday, 8th, 10:45-11:45

Several books document parts of the emerging standard architectural style for building enterprise computing systems using OO technology. Martin Fowler's book "Patterns of Enterprise Application Architecture" is the most well-known, but Eric Evan's "Domain Driven Design" describes some key aspects of this style that Martin Fowler does not describe, and is closely related. Both of these books emphasize the importance of the domain model, but neither describe the patterns of the domain model. These patterns are described in other books, such as Fowler's "Analysis Patterns", Silverston's "The Data Model Resource Book" and Hay's "Data Model Patterns". This talk will show how these books are related and what is still missing to document the architectural style of building enterprise applications based on object-oriented domain models.

Ralph Johnson is Research Associate Professor at the University of Illinois at Urbama-Champaign. He is one of the four co-authors of "Design Patterns" and the conference chair of the first PLoP. He has been to every PLoP since, in large part because they have been close to his home and organized by his students and ex-students. He is an editor of the new Transactions on Pattern Languages of Programming and will be twisting arms at PLoP to get people to help.

Accepted Papers

All accepted papers were organized by different categories, based on their type (pattern paper vs regular paper), its potential usefulness, and its level of maturity, and assigned to different sessions: Writers' Workshops, Writing Group, or Presentation.

To increase feedback, all papers are part of a Writers' Workshop. Papers of the Writing Group will be selected to be workshoped depending on their evolution during the conference.


Wednesday, September 5
10:30-11:00Coffee Break
14:45-15:00Coffee Break

Conference registration

Welcome Reception

The Welcome Reception at PLoP is a Papa Dell's Pizza Reception and an Open Bar. It will start at 6pm but the end is open.

During the Welcome Reception the organizers welcome all the participants and is provided a quick introduction to all PLoP activities.

Newcomers Orientation, by Bob Hanmer and Linda Rising

This session is aimed for Newcomers to provide them a quick orientation about a PLoP conferences.

Evening Activities, Focus Groups, BoFs

At the end of the day, there is free time for you to decide what to do: to meet people in the Bar, to lead or join a Focus Group or BoF, to know Allerton better, to work on your paper, etc.

Thursday, September 6

Several games will be led by Bob Hanmer and Linda Rising to help you know other participants, activate the non-technical halfs of our brains, and build up a community of trust. Games are one of the unique features of the PLoP series of conferences.

Writers' Workshop Demonstration

A mock Writers' Workshop demonstrates how the main activity of PLoP is run. A pattern is previously selected to be discussed during this demonstration. During the workshop, a narrator will explain and point its most important parts and happenings. The paper chosen is A Pattern of Their Own", by Mary Lynn Manns.

10:30-11:00Coffee Break
Workshop Preparation

Workshop participants meet together with their workshop leaders to organize the several sessions of the workshop, basically to assign the papers to sessions, so that everyone can get adequately prepared for each session.

This year, there are 4 groups of papers:

Each group has 4-5 papers, and includes 1 paper assigned for the Writing Group.

Assignments of papers to groups are posted on the list of accepted papers.

Reading Time, Allerton Time, Mentoring Time

For many participants, this could be a free time period for you to do whatever you want or need.

Those that haven't read all the papers, can use it to read more while knowing better Allerton house and gardens.

Those with papers assigned to the Writing Group, this would be an opportunity to meet with their mentor to get feedback and work on their paper.

Writers' Workshop I

Writers' workshops are the primary focus of our time at PLoP and in them we discuss the accepted papers.

The format of Writers' Workshops has been adopted from poetry review. Each writers' workshop contains 5 papers, which authors must read before the conference to be able to give each other feedback on their work in a peer review session of around one hour per paper.

In each of the 5 sessions, the authors of the paper under discussion remain silent while the others discuss it and explain additional insights and views they have about it.

Non-authors are free to choose the writers' workshop group they want, but are supposed to stay with their workshop over the entire conference, to benefit more from it.

A fruitful participation in a Writers' Workshop requires to read its papers in advance and, if possible, to take some notes on what you liked about the papers and what you think needs improvement. Since there is only small periods of reading time during the Writers' Workshops and experience shows that chatting with others or meeting people is much more fun than being alone reading papers, do yourself a favor and read the papers of your Writers' Workshop in advance.


Afternoon games

14:45-15:00Coffee Break
Presentations I, II

Authors with papers accepted for Presentation will be provided a period of 30 min, including a paper presentation during no more than 20 min, followed by a period of questions and discussion of around 10 min.

I. "Pattern design in the context space: A methodological framework for designing auditory display with patterns" , by Christopher Frauenberger, Tony Stockman, Marie-Luce Bourguet.

II. "Software Pattern Communities: Current Practices and Challenges" , by Scott Henninger, Victor Correa.

Writers' Workshops II

2nd session of the Writers' workshops.

Day Review

The day is almost over, so it is time for Day Review, when we will meet all together and briefly review what happened, what we did, and what we will do after dinner till the end of the day.

Invited Talk I - "Design Beyond Human Abilities", by Richard Gabriel

Please see abstract and details above.

Evening Activities, Focus Groups, BoFs

At the end of the day, there is free time for you to decide what to do: to meet people in the Bar, to lead or join a Focus Group or BoF, to know Allerton better, to work on your paper, etc.

Friday, September 7
Day Overview

What will happen on this second day of PLoP? A lot! This Day Overview session will help you know exactly what.


More Games to warm up body and mind.

Writers' Workshop III

3rd session of the Writers' workshops.

10:30-11:00Coffee Break
Invited Talk II - "Are Agilists the Bonobos of Software Development?", by Linda Rising

Please see abstract and details above.

Presentations III, IV

Time to listen to two more papers accepted for Presentation (30 min = 20 min presentation + 10 min of discussion).

III. "A Pattern Story for Aspect-Oriented State Machines" , by Mark Mahoney, Tzilla Elrad.

IV. "Design Patterns in Eos" , by Hridesh Rajan.


Indoor games

Presentation V

Time for another paper accepted for Presentation (30min = 20min presentation + 10 min of discussion).

V. "A Metric for Measuring Abstraction Level of Design Patterns" , by Atsuto Kubo, Hironori Washizaki, and Yoshiaki Fukazawa.

14:45-15:00Coffee Break
Reading Time, Allerton Time, Mentoring Time

More free time to read, to see Allerton, or to work in your paper.

Writers' Workshops IV

4th session of the Writers' workshops.

Day Review

What happened today? Time to know it in this Day Review.

Shepherding Workshop, by Bob Hanmer

Bob Hanmer, one of the veteran pattern writers, shepherds, and instructors, will lead a session aimed at helping us all being better shepherds. Those of you who have written a PLoP paper know just how important shepherds are to PLoP. They are the lifeblood of the community.

Even if your paper at PLoP'2007 was your first pattern-writing experience, we encourage you to look toward being a shepherd for future pattern events. This workshop will help you begin to contribute as a shepherd. If you are a PLoP veteran, please join us, too, to work toward being a better shepherd.

Evening Activities, Focus Groups, BoFs

'Evening has arrived... free time for you to meet people in the Bar, to lead or join a Focus Group or BoF, to know Allerton better, to work on your paper, etc.

Saturday, September 8
Day Overview

What will happen on this third day of PLoP? Many activities! This Day Overview session will help you know exactly what.


More funny and interesting games.

Writers' Workshop V

5th session of the Writers' workshops. This last session will be assigned for papers accepted for the Writing Group, which during the conference were evolved with the help of a dedicated mentor.

10:15-10:45Coffee Break
Invited Talk III - Patterns of Enterprise Application Architecture, by Ralph Johnson

Please see abstract and details above.

Retrospective and Closing, by Linda Rising

PLoP is almost over... now is the right time to reflect on what we enjoyed, what we learned, and what can be changed for future PLoP's.

We will be led by Linda Rising in a retrospective on PLoP'2007.

This Closing session is also a good time to give and receive last gifts, provide a brief preview of the next PLoP conference and say

'Till PLoP'2008!


A last meal together at PLoP'2007!