Come, Let's Play

by Harel, David; Marelly, Rami

• ISBN13: 9783540007876
• ISBN10: 3540007873
• Edition: CD
• Format: Hardcover
• Copyright: 2003-08-01
• Publisher: Springer Verlag

Summary

This book presents a powerful new language and methodology for programming complex reactive systems in a scenario-based manner. The language is live sequence charts (LSCs), a multimodal extension of sequence charts and UML's sequence diagrams, used in the past mainly for requirements. The methodology is play-in/play-out, an unusually convenient means for specifying inter-object scenario-based behavior directly from a GUI or an object model diagram, with the surprising ability to execute that behavior, or those requirements, directly. The language and methodology are supported by a fully implemented tool - the Play-Engine - which is attached to the book in CD form. Comments from experts in the field: The design of reactive systems is one of the most challenging problems in computer science. This books starts with a critical insight to explain the difficulty of this problem: there is a fundamental gap between the scenario-based way in which people think about such systems and the state-based way in which these systems are implemented. The book then offers a radical proposal to bridge this gap by means of playing scenarios. Systems can be specified by playing in scenarios and implemented by means of a Play-Engine that plays out scenarios. This idea is carried out and developed, lucidly, formally and playfully, to its fullest. The result is a compelling proposal, accompanied by a prototype software engine, for reactive systems design, which is bound to cause a splash in the software-engineering community. Moshe Y. Vardi, Rice University, Houston, Texas, USA Scenarios are a primary exchange tool in explaining system behavior to others, but their limited expressive power never made them able to fully describe systems, thus limiting their use. The language of Live Sequence Charts (LSCs) presented in this beautifully written book achieves this goal, and the attached Play-Engine software makes these LSCs really come alive. This is undoubtedly a key breakthrough that will start long-awaited and exciting new directions in systems specification, synthesis, and analysis. Gèrard Berry, Esterel Technologies and INRIA, Sophia-Antipolis, France The approach of David Harel and Rami Marelly is a fascinating way of combining prototyping techniques with techniques for identifying behavior and user interfaces. Manfred Broy, Technical University of Munich, Germany

Author Biography

David Harel is the Dean of the Faculty of Mathematics and Computer Science at the Weizmann Institute of Science in Israel. He is also co-founder of I-Logix, Inc., Andover, MA, and of SenseIT Technologies, Ltd. (DigiScents Israel). His research interests are in theoretical computer science (especially computability, automata theory and logics of programs), and in software and systems engineering (especially specification and modeling, object-oriented analysis and design, and visual languages), as well as the aesthetic layout of diagrams, clustering algorithms and the synthesis and communication of smell. He is the inventor of the language of statecharts (1983), was part of the team that designed the Statemate (1984-1987) and Rhapsody (1997) tools, and was co-inventor of LSCs (1998). His work is central to the behavioral aspects of the UML. He devotes part of his time to expository work: In 1984 he delivered a lecture series on Israeli radio, and in 1998 he hosted a series on Israeli television; some of his writing is intended for a general audience (see, for example, Computers Ltd.: What They Really Can't Do , Oxford University Press, September 2000). He has received a number of awards, including ACM's Karlstrom Outstanding Educator Award in 1992, and the 1997 Israeli Prime Minister's Award for Software. His book, Algorithmics: The Spirit of Computing (Addison-Wesley, 1987, 2nd. edn. 1992) was the Spring 1988 Main Selection of the Macmillan Library of Science. He is a Fellow of the ACM and of the IEEE.

Table of Contents

Part I. Prelude
1. Introduction	3	(6)
1.1 What Are We Talking About?	3	(3)
1.2 What Are We Trying to Do?	6	(1)
1.3 What's in the Book?	7	(2)
2. Setting the Stage	9	(16)
2.1 Modeling and Code Generation	9	(3)
2.2 Requirements	12	(2)
2.3 Inter-Object vs. Intra-Object Behavior	14	(2)
2.4 Live Sequence Charts (LSCs)	16	(1)
2.5 Testing, Verification and Synthesis	17	(4)
2.6 The Play-In/Play-Out Approach	21	(4)
3. An Example-Driven Overview	25	(30)
3.1 The Sample System	25	(1)
3.2 Playing In	26	(13)
3.3 Playing Out	39	(4)
3.4 Using Play-Out for Testing	43	(1)
3.5 Transition to Design	44	(2)
3.6 Time	46	(1)
3.7 Smart Play-Out	47	(8)
Part II. Foundations
4. The Model: Object Systems	55	(4)
4.1 Application Types	55	(1)
4.2 Object Properties	56	(2)
4.3 And a Bit More Formally	58	(1)
5. The Language: Live Sequence Charts (LSCs)	59	(24)
5.1 Constant LSCs	60	(2)
5.2 Playing In	62	(3)
5.3 The General Play-Out Scheme	65	(3)
5.4 Playing Out	68	(3)
5.5 Locations Combining and Messages	71	(2)
5.6 And a Bit More Formally	73	(8)
5.7 Bibliographic Notes	81	(2)
6. The Tool: The Play-Engine	83	(8)
6.1 Bibliographic Notes	87	(4)
Part III. Basic Behavior
7. Variables and Symbolic Messages	91	(14)
7.1 Symbolic Scenarios	91	(3)
7.2 Enriching the Partial Order	94	(3)
7.3 Playing Out	97	(2)
7.4 And a Bit More Formally	99	(4)
7.5 Bibliographic Notes	103	(2)
8. Assignments and Implemented Functions	105	(14)
8.1 Using Implemented Functions	105	(3)
8.2 Assignments	108	(3)
8.3 Playing Out	111	(3)
8.4 And a Bit More Formally	114	(5)
9. Conditions	119	(14)
9.1 Cold Conditions	119	(1)
9.2 Hot Conditions	120	(1)
9.3 Playing In	121	(5)
9.4 Playing Out	126	(2)
9.5 And a Bit More Formally	128	(4)
9.6 Bibliographic Notes	132	(1)
10. Branching and Subcharts	133	(16)
10.1 The If-Then-Else Construct	133	(1)
10.2 Subcharts	134	(1)
10.3 Nondeterministic Choice	135	(1)
10.4 Playing In	136	(2)
10.5 Playing Out	138	(3)
10.6 And a Bit More Formally	141	(5)
10.7 Bibliographic Notes	146	(3)
Part IV. Advanced Behavior: Multiple Charts
11. Executing Multiple Charts	149	(10)
11.1 Simultaneous Activation of Multiple Charts	149	(5)
11.2 Overlapping Charts	154	(3)
11.3 And a Bit More Formally	157	(2)
12. Testing with Existential Charts	159	(16)
12.1 Specifying Test Scenarios	159	(1)
12.2 Monitoring LSCs	160	(3)
12.3 Recording and Replaying	163	(1)
12.4 On-line Testing	164	(1)
12.5 Executing and Monitoring LSCs in the Play-Engine	165	(1)
12.6 And a Bit More Formally	166	(5)
12.7 Bibliographic Notes	171	(4)
Part V. Advanced Behavior: Richer Constructs
13. Loops	175	(14)
13.1 Using Loops	175	(1)
13.2 Playing In	176	(2)
13.3 Playing Out	178	(1)
13.4 Using Variables Within Loops	179	(2)
13.5 Executing and Monitoring Dynamic Loops	181	(2)
13.6 And a Bit More Formally	183	(4)
13.7 Bibliographic Notes	187	(2)
14. Transition to Design	189	(20)
14.1 The Design Phase	189	(1)
14.2 Incorporating Internal Objects	190	(3)
14.3 Calling Object Methods	193	(3)
14.4 Playing Out	196	(2)
14.5 External Objects	198	(3)
14.6 And a Bit More Formally	201	(4)
14.7 Bibliographic Notes	205	(4)
15. Classes and Symbolic Instances	209	(20)
15.1 Symbolic Instances	209	(1)
15.2 Classes and Objects	210	(2)
15.3 Playing with Simple Symbolic Instances	212	(1)
15.4 Symbolic Instances in the Main Chart	213	(2)
15.5 Quantified Binding	215	(1)
15.6 Reusing a Scenario Prefix	216	(2)
15.7 Symbolic Instances in Existential Charts	218	(1)
15.8 An Advanced Example: NetPhone	218	(3)
15.9 And a Bit More Formally	221	(6)
15.10 Bibliographic Notes	227	(2)
16. Time and Real-Time Systems	229	(22)
16.1 An Example	229	(1)
16.2 Adding Time to LSCs	230	(1)
16.3 Hot Timing Constraints	231	(3)
16.4 Cold Timing Constraints	234	(1)
16.5 Time Events	235	(1)
16.6 Playing In	236	(1)
16.7 Playing Out	237	(2)
16.8 Unification of Clock Ticks	239	(1)
16.9 The Time-Enriched NetPhone Example	240	(2)
16.10 And a Bit More Formally	242	(5)
16.11 Bibliographic Notes	247	(4)
17. Forbidden Elements	251	(30)
17.1 Example: A Cruise Control System	251	(1)
17.2 Forbidders Messages	252	(3)
17.3 Generalized Forbidden Messages	255	(1)
17.4 Symbolic Instances in Forbidden Messages	256	(2)
17.5 Forbidden Conditions	258	(4)
17.6 Scoping Forbidden Elements	262	(2)
17.7 Playing Out	264	(2)
17.8 Using Forbidden Elements with Time	266	(1)
17.9 A Tolerant Semantics for LSCs	267	(1)
17.10 And a Bit More Formally	268	(9)
17.11 Bibliographic Notes	277	(4)
Part VI. Enhancing the Play-Engine
18. Smart Play-Out (with H. Kugler)	281	(28)
18.1 Introduction	281	(2)
18.2 Being Smart Helps	283	(4)
18.3 The General Approach	287	(2)
18.4 The Translation	289	(10)
18.5 Current Limitations	299	(2)
18.6 Satisfying Existential Charts	301	(6)
18.7 Bibliographic Notes	307	(2)
19. Inside and Outside the Play-Engine	309	(8)
19.1 The Engine's Environment	309	(1)
19.2 Playing In	310	(1)
19.3 Playing Out	311	(2)
19.4 Recording Runs and Connecting External Applications	313	(1)
19.5 Additional Play-Engine Features	313	(4)
20. A Play-Engine Aware GUI Editor	317	(6)
20.1 Who Needs a GUI Editor?	317	(1)
20.2 GUIEdit in Visual Basic	318	(1)
20.3 What Does GUIEdit Do?	318	(3)
20.4 Incorporating Custom Controls	321	(1)
20.5 GUIEdit As a Proof of Concept	321	(1)
20.6 Bibliographic Notes	322	(1)
21. Future Research Directions	323	(10)
21.1 Object Refinement and Composition	323	(2)
21.2 Object Model Diagrams, Inheritance and Interfaces	325	(1)
21.3 Dynamic Creation and Destruction of Objects	326	(1)
21.4 Structured Properties and Types	327	(1)
21.5 Linking Multiple Engines	328	(5)
Part VII. Appendices
A. Formal Semantics of LSCs	333	(24)
A.1 System Model and Events	333	(3)
A.2 LSC Specification	336	(6)
A.3 Operational Semantics	342	(15)
B. XML Description of a GUI Application	357	(4)
C. The Play-Engine Interface	361	(2)
C.1 Visual Basic Code	361	(2)
D. The GUI Application Interface	363	(4)
D.1 Visual Basic Code	364	(3)
E. The Structure of a (Recorded) Run	367	(2)
References	369	(6)
Index	375